Browsing by Author "Singhalage, I.D."

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    Antioxidant Activity of Selected Ten Underutilized Fruit Species
    (Uva Wellassa University of Sri Lanka, 2018) Dilani, V.J.; Singhalage, I.D.
    The study was conducted to assess the antioxidant potential of ten underutilized fruit species namely Phyllanthus emblica L,Flacourtia sp.,Elaeocarpus serratus L., Phyllanthus acidus (L.) Skeels , Averrhoa carambola L., Averrhoa bilimbi L., Cynometra cauliflora L., Morus sp., Spondias sp. and Manilkara zapota (L.) P.Royen grown in Sri Lanka. Fruit extracts were prepared by centrifuging (4500 rpm) finely ground fresh fruit samples (20 g) with distilled water (40 ml) for 90 minutes. The extraction was repeated twice and the supernatants were used for analysis. Total Ascorbic Acid Content (TAsC) was determined using an iodomatric titration technique, calculated as mol per gram of fresh weight. Antioxidant potential was determined using DPPH• and ABTS•+ radical scavenging assays. The DPPH• Radical Scavenging Activity (RSA) of the extracts was expressed as IC50 values. The ABTS•+ activity (RSA) was calculated as percentage of discoloration. This experiment was conducted by following complete randomized design with 3 replicates. Ascorbic acid was used as a positive control and distilled water was used as a negative control. The TAsC varied among the species from 0.125x10-3 ± 0.000025 mol g- of fresh fruit of C. cauliflora L. to 4.608 x 10-3 ± 0.0001665 mol g - of fresh fruit of P. emblica L. The TAsC and antioxidant activity (DPPH• and ABTS•+ assays) were found in order to, C. cauliflora L.< Spondias sp.
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    Cellulase Activity of Fungal and Bacterial Isolates and their Fungal-bacterial Biofilms
    (Uva Wellassa University of Sri Lanka, 2021) Singhalage, I.D.; Palliyaguruge, A.P.; Kannangara, U.D.; Seneviratne, G.; Madawala, H.M.S.P.; Yogarajah, K.
    Enzymes are crucial in speeding up many biological reactions, but the lack of suitable sources to extract them with high productivity in low cost is a constraint. Present study designed in order to evaluate the cellulase production by some fungal and bacterial isolates and their fungal-bacterial biofilms (FBBs). Five fungal (F1-F5) and 27 bacterial (B1-B27) strains were isolated from soil samples collected from a municipal garbage dump near Vincent Dias Stadium, Badulla, Sri Lanka. All bacterial isolates were screened for cellulase activity using Congo Red Agar medium. Two strains (B6 and B15) with significant (p ≤ 0.05) cellulase activity were selected along with all fungal strains for biofilm formation. Accordingly, ten fungal-bacterial combinations (F1B6, F1B15, F2B6, F2B15, F3B6, F3B15, F4B6, F4B15, F5B6, F5B15) were used for the formation of biofilms under in vitro conditions. The biofilm formation was monitored regularly through microscopic means. On day four, three successful biofilms (B6F1, B15F1 and B15F4) were resulted with bacterial cell attachment to mycelia. These three mixed-culture biofilms and their monoculture counterparts were re-cultured in Czapek-Dox broth with the culture medium alone as a control. On day four , a portion of the broth was centrifuged and the supernatant was used as the crude cellulase extract. The extracts were then tested for their efficacy through a well diffusion assay using Carboxymethyl Cellulose agar medium in a Complete Randomized Design with three replicates. The diameters of the clear zones around the wells were measured and the data were analyzed by one-way ANOVA and t-test. The B15F1 showed a significantly higher cellulase activity over F1, the second highest cellulose producer (p = 0.02). F3 and F4 also showed considerably high levels of cellulase activity. The least cellulase activities were shown by B6 and B15. Thus, the fungal-bacterial biofilm B15F1 can be introduced as a potential source for bulk extraction of cellulases. However, further studies are needed to find out the optimal maturation stage with the highest cellulase activity of the biofilm, B15F1. Keywords: Cellulase; Bacteria; Fungi; Fungal-bacterial biofilms
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    Degradation of Cellulose and Pectin in Organic Wastes by Developed Fungal-Bacterial Biofilms
    (Uva Wellassa University of Sri Lanka, 2018) Wickramage, K.C.; Singhalage, I.D.; Seneviratne, G.
    An organic waste consists of cellulose and pectin which are resistant to rapid degradation due to their complexity. The objective of this study was to find out the most efficient fungal-bacterial biofilm/s (FBB/s) for the organic waste degradation. Pectinolytic and cellulolytic activity of isolates were tested by standard plate assays and best strains were used to develop 25 FBBs. The best FBBs were selected based on the physical attachment of bacterial cells to fungal filaments (light microscopic observations), and those were symbolized as F3B1, F5B1, F2B2, F3B2, F3B3, F4B3, F2B5 and F3B5. Coffee silver skin, barely skin and rice husk were the organic wastes used. Developed FBBs were inoculated separately to 10 g of above wastes in petri dishes and were incubated for 40 days. The control was maintained without FBBs inoculation. Three replicates were maintained for each treatment and the experiment was arranged in a completely randomized design. The mass reduction, Fourier Transform Infrared Spectroscopy (FTIR) and sugar accumulation of samples were analyzed within five day intervals. Data were analyzed by ANOVA. Results revealed that in the 40th day, the sugar production was highest in barley husk treated by F3B5. In coffee silver skin, the sugar accumulation was similar under all FBBs. In rice husk, F3B1 showed the highest sugar level in 15th day, but F4B3 dominated on the 25th day. The mean weights of the samples decreased with time, but after 25th day they came into a plateau with having 0.1-0.3 % weight loss percentage. According to FTIR data, all FBBs except F3B3 showed the degradation of barely husk. F2B5 was the best in terms of weight loss during the last five days of incubation. F4B3, F3B2 and F5B3 were the best biofilms in terms of weight loss at the end of 10th, 15th and 20th days, respectively. It can be concluded that F3B3 and F3B2 were the best FBBs for degradation of all three types of organic wastes. Keywords
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    Degradation of Cellulose and Pectin in Organic Wastes by Selected Fungal Strains
    (Uva Wellassa University of Sri Lanka, 2018) Hennayake, H.M.C.R.K.; Singhalage, I.D.
    Solid waste management is becoming more complicated due to rise in population, industrialization and changes in life styles. In nature, microbial diversity exhibits wide range of activity, association and interaction with each other and with their environment. Microbes releasing pectinolytic and cellulolytic enzymes are playing a major role in degradation and decomposition of organic compounds. This study aimed to investigate the degradation of cellulose and pectin in organic waste by fungi. A total of 10 fungal species were isolated from waste samples collected from municipal waste dump near Vincent Dias stadium in Badulla. Pectinolytic and cellulolytic activity of isolates were tested by standard plate assays and best strains to degrade cellulose and pectin were selected (F3, F6A, F6B, F8 and F10). Selected fungal species were inoculated to particles (> 1 cm diameter) of corn cobs, banana peduncle and jack fruit axis and incubated under laboratory conditions. Weight loss percentage (WL %), sugar production and Fourier Transform Infrared (FTIR) spectroscopy data were gathered from samples within 5 days interval for 50 days. Experiment was conducted by following complete randomized design with three replicates. The highest weight loss percentage was obtained in F10 treated corn cobs sample (WL% = 1.3). Weight loss percentages and sugar analysis values with respect to the time started to be static after 45 days. It may be due to the fact that the microbial growth has entered a stationary phase' since available nutrients have decreased in the medium. According to the FTIR data, the F3 and F6B treated corn cob samples and F8 treated banana peduncle samples had significantly high (p < 0.05) absorbance in polysaccharide window (900 — 1200 cm-1) at the fifth day of incubation. In conclusion, all fungi stains used in the study have the ability to degrade organic waste efficiently.
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    Determination of Pectinase Activity of Selected Bacterial and Fungal Strains
    (Uva Wellassa University of Sri Lanka, 2021) Yogarajah, K.; Singhalage, I.D.
    Enzymes have been utilized to speed up the biological reactions in industrial productions. Enzymatic methods are environmentally friendly, low cost in production and disposal but the limitation of sources to extract different enzymes is an issue. Therefore, the current research aimed in order to determine the pectinase activity of selected bacterial and fungal strains isolated from a municipal garbage dump. Thirty-four bacterial (B1–B34) and five fungal (F1-F5) strains taken from the culture collection were activated in Nutrient Agar (NA) and Potato Dextrose Agar (PDA) respectively. For the enzymatic assay, the bacterial and fungal strains were re-cultured in NutrientBroth (NB) and Potato Dextrose Broth (PDB) respectively. The culture medium collected on day four was centrifuged and cell free supernatants were then tested for pectinase activity by well diffusion assay conducted in Pectinase Screening Agar medium (PSA) by following the Complete Randomized Design with three replicates. The NB alone was the control. Diameters of halo zones formed around the wells were measured at day four as the data. Data were analyzed by one way ANOVA. The bacterial culture, B16 showed the highest pectinase activity among bacterial strains. F3 showed significant (p ≤ 0.05) pectinase activity among fungal strains. The study was further elaborated to find out the optimal maturity stage of B16 and F3 with the highest pectinase activity. For that, B16 were re-cultured in NB and F3 was re-cultured in PDB. The crude enzyme was extracted from the subsamples collected from each medium within 6 hr time intervals and used to digest pectine and the amounts of sugar formation after the pectine digestion was evaluated by DNSA method. The B16 showed highest pectinase activity (2.95 AU) at 72 and 78 hours of inoculation whereas F3 showed the highest pectinase activity (1.43 AU) between 54 and 78 hours of inoculation. Thus, the pectinase activity of B16 is higher than that of F3. Therefore, B16 of present study can be introduced as an efficient culture to extract pectinase enzyme in bulk for industrial applications. Keywords: Bacteria; Fungi; Pectinase
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    Determination of Pectinase and Cellulase Activity of Fungi Species Isolated from Unsanitary Landfill in Badulla
    (Uva Wellassa University of Sri Lanka, 2020) Thennakoon, T.M.A.R.S.; Singhalage, I.D.; Maheshika, W.A.H.
    Municipal solid waste is one of the major sources for microbes having potent enzymatic activities. The positive impacts of such microbes could use for finding a suitable solution to overcome waste-related problems. The present study aimed at isolating and determining pectinase and cellulase activity of fungal strains living in unsanitary landfills. Fungi species were isolated in Potato Dextrose Agar medium. The isolated fungal strains were distinguished from each other by examining their morphological features through the light microscope after culturing them in slides. All fungal isolates were tested for cellulase and pectinase activities by using Carboxymethylcellulose and Vincent’s agar plates respectively. The good diffusion method was used in both assays. The diameter of the clearance zone around the wells was measured after the incubation. Data were analysed by ANOVA in Minitab 17.1. According to the results, a total of 29 fungal species were isolated and coded from F1-F29. Among them, 21 species were positive for pectinase activity whereas 20 species were positive for cellulase activity. The significant (p < 0.05) mean diameter for pectinase activity was given by F22 (40 mm) and for cellulase activity by F9 (19 mm). Eight fungi isolates (F22, F16, F23, F9, F24, F25, F15, and F2) were shown both pectinase and cellulase activities. Thus, such cultures having positive pectinase and cellulase activities could be useful in organic waste management in unsanitary landfills. The fungal species having pectinase and cellulase activities yet to be identified. Keywords: Unsanitary landfill, Fungi, Pectinase, Cellulase
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    Development of a Cereal Incorporated Yoghurt
    (Uva Wellassa University of Sri Lanka, 2012) Ramawickrama, P.; Danasekara, D.M.J.N.; Singhalage, I.D.
    Yoghurt, thought to have been part of Balkans and the Mediterranean countries for a longer time in the history (Early, 1998), is a popular nutritional healthy food serves as a snack and a dessert. Yoghurt is a fermented milk product which is partially digested by microorganisms. Under the standard of identity established by the U.S. Food and Drug Administration (FDA), in order for a refrigerated product to be called "yogurt," it must be produced by culturing permitted dairy ingredients with a bacterial culture, which contains Lactobacillus bulgaricus and Streptococcus thermophilus. In addition to the use of bacterial cultures required by the FDA standard of identity, live and active culture yogurt may contain other safe and suitable food grade bacterial cultures. Yoghurt has a higher nutritional profile and known to have many health benefits. Yoghurt is a good solution for lactose intolerance, due to several factors including the activity of live bacteria in the yogurt or the digestive action of other enzymes on lactose such as bacterial p-galactosidase. The increased viscosity of yogurt compared with milk has also been suggested as a potential explanation, as this may result in slower emptying from the stomach and thus a longer transit through the gastrointestinal tract, which in turn may improve the absorption and reduce the amount of lactose present in the colon. Studies have also shown that consumption of milk and dairy foods as part of a calorie controlled diet is associated with increased weight loss, particularly form the abdomen, amount of lactose present in the colon. Yoghurt is healthy option for obesity. The action of probiotics is another health benefit of yoghurt. Probiotics can exert a positive effect on health by redressing the balance of health-promoting and pathogenic bacteria in the gastrointestinal tract. Cereals are grasses cultivated for edible components of their fruit seeds. Cereals play an important role in meals. Rice varieties are staple food of Asians. Many cereals have a very good role in the breakfast and snacks in other corners of the world. Focusing on the nutritional factors, cereals are known to possess dense nutritional properties with less calories and sugar. They manage the blood sugar levels and body weight. Cereal plays major roles in health by reducing the risk of coronary heart diseases and cancers of stomach and colon. A cereal with milk is a leading source of nutrients in children's diet. Incorporating both nutritional sources, this study was aimed to develop a ready — to — serve cereal incorporated yoghurt as a new yoghurt product, while adding value to local cereal varieties such as Rice (Oryza saliva) and Finger millet (Eleusinecoracana). The law fat content and medicinal value of cereals opens a broad market segment for this yoghurt. Considering its health impacts, this yogurt can be marketed for elders among whom the yogurt is not much popular.
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    Development of Microbial Biofertilizer for Tomato (Solanum Lycopersicum)
    (Uva Wellassa University of Sri Lanka, 2019) Maheshika, W.A.H.; Singhalage, I.D.; Henagamage, A.P.; Seneviratne, G.
    Extensive application of chemical fertilizers and agrochemicals has led to environmental and health issues, and has contributed to climatic changes. In order to minimize the usage of them, environmental friendly biofertilizers containing inoculants of beneficial microorganisms have been introduced. Present study aims in investigating a microbial biofertilizer for tomato, a vegetable highly dependent on the chemical fertilizers (CFs). Bacterial species living in tomato rhizosphere were isolated in Nutrient Agar medium. Growth medium pH, growth in N free Combined Carbon Medium (CCM), phosphate solubilization, indole acetic acid (IAA) production and lettuce seed germination assay were conducted for them and 8 isolates ( J, C, S, F, I, R, B, E) were selected for tomato plant assay. Those isolates were inoculated to soil in tomato planted pots in triplicate. Recommended dosage of CFs for tomato was taken as positive control and a negative control was maintained without adding CFs or microbes. Plant height, number of leaves and flowering were recorded at 10th week and data were analyzed by ANOVA in minitab16.1. The highest clear zone diameter (40 mm) in phosphate solubilization and highest absorbance in IAA were given by isolate C. Inoculants B, R, S changed the colour of CCM into blue, while J, E, I, F, C changed the colour of medium to yellow. In lettuce seed germination assay, the highest vigor and germination percentage were observed in B (246) and F (82%), respectively. All bacterial isolates significantly (p ≤ 0.05) improved plant height over the controls. The highest mean plant heights were observed under bacterial strains C (93 cm), S (91 cm), F (91 cm) and E (90 cm). Plant treated with C showed the significantly increased leaf number per plant over the other species and the controls. Flower number was highest in E and F treated plants. In conclusion, bacterial strains associated with tomato rhizosphere have the potential to be used as biofertilizers to improve the vegetative growth of tomato.
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    Development of Minimally Processed Banana Blossom (Musa acuminate colla)
    (Uva Wellassa University of Sri Lanka, 2011) Senevirathne, W.M.N.S.; Singhalage, I.D.; Madhusinghe, M.M.G.; Wijesekara, K.B.
    Note: See the PDF Version Minimally processing of fruits and vegetables is a i rapidly developing segment of the food industry. The manufacturing steps of minimally processed products involve washing, sorting, yelling, slicing, blanching and package "S IU fi I iris, The wound responses are the major problem of fresh cut development which case the enzymatic browning (Wickraiaiaiaclachii and Ramaiiitikaaracliclii, 2005) leaning to the reduction of visual and organoleptic quality. Control of wound responses are the key to produce minimally processed product if S°0d quality (Jaiiisicwicz e/ ml., 1999), Blanching is an important treatment which primarily aims at inacti voting the enzymes that cause undesirable changes (Kaui anti Kapoor, 2000). The increase in cut damaged surfaces ani4 availability of cell u nutrients (Delaqtiis e/ ri/., 2003) and i increase’s hand ling (Dat iiaabaudu c/ p/., 2007) of the products provide greater opportunity for contamination by pathogenic organisms. Minimally proceed vegetables are rare iii the Sri Lankan market. Therefore, the major objective of this research is to develop a minimally processed vegetable front consumption constricted local banana blossom.
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    Development of Wine from Jack Fruit (Artocarpus Heterophyllus): A Value Added Product from a Tropical Fruit Crop in Sri Lanka
    (Uva Wellassa University of Sri Lanka, 2011) Kaushallya, H.K.H.N.; Henagamage, A.P.; Singhalage, I.D.; Madusinghe, M.M.G.
    Note: See the PDF Version Introduction Wine is an alcoholic beverage typically made from fermented grape juice or variety of fruits. Since fruits have natural sugar and natural acids, they provide all the required Ingredients for making wine. The quality and the type fruit dictate the final quality of the trait-based wine. Therefore. selection of correct fruit commodity is critical in wine making (Fitli riad i c/ p/., 1996). Jackfruit is an extensively grown and very important tree for the people of Sri Lanka. It is essentially a carbohydrate food and is useful as a source of energy. The perianth is rich in sugars, contains carotene, protein, fat, calcium, phosphorous, and iron in quantities similar to those found in other fruits which are used to manufacture wine (Pushpakumara ct at., 2007). Therefore, Jackfruit it can be considered as a potential fruit crop in making wine. Wine is produced by fermenting crushed fruits using various types of yeasts, the majority of the yeast used iii baking is Saccliaromyces cere visiae, which is the same species commonly used in alcoholic fermentation, and so is also called brewer's yeast (Pelcza er>/., 1977). Therefore, this study was carried out to prepare wine front Jackfruit it juice with the baker’s yeast as a low cost method for wine making and to compare the sensory attributes and quality parameters with commercial red wine front grape.
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    Effect of substrate on biochemical expression of Bacterial Biofilms
    (Uva Wellassa University of Sri Lanka, 2015) Lakmali, N.A.D.; Singhalage, I.D.; Ediriweera, E.P.S.K.; Senevirathne, G.
    Single or multi species bacteria are agglomerated together with the help of Extracellular Polymeric Substance (EPS) forming bacterial biofilms (BBs). BBs get attached to the biotic or abiotic surfaces. This surface based adhesion alters the biochemical expression of BBs. Under the optimum conditions, the biochemical expression of BBs can be maximized. The BBs can be used in various biotechnological applications like biofertilizers, drug discovery, biofuels etc. (Senaviratne, et al., 2008). Thus, present study figure outs preferable surface for the BBs, which would enhance the functional properties of BBs. Methodology In this experiment, single species bacterial biofilms were formed in glass wool (G), metal fibers (M) and fungal filaments (F) immersed in a Low Cost Medium (LCM). Control (C) was maintained without surfaces or bacterial strain. There were three replicates for each treatment. Completely Randomized Design was followed as the experimental design. Attachment of bacterial biofilm with different surfaces was observed through the microscopy. Biochemical expressions of different biofilms were examined by analyzing the exudates using Fourier Transform Infrared (FTIR) print, polysaccharide, amide, fatty acid I, II, and mixed. Cluster analysis was performed under each window to see the similarity and the differences of the biochemical expressions of bacterial biofilms attached with different surfaces. Statistical analysis was done by using Minitab statistical package (version 16).
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    Extraction of Lactic Acid from Corn Kernels using Streptococcus thermophilus and Method Optimization
    (Uva Wellassa University of Sri Lanka, 2019) Amaraweera, A.P.S.M.; Senevirathna, M.A.S.R.; Singhalage, I.D.
    Lactic Acid (LA) has several applications in pharmaceutical, cosmetic and polymer industries. Nowadays, the polymer industries focus on polylactic acid (PLA), which is a biodegradable polymer. LA is the monomer of PLA and it is an alpha hydroxy acid which can be synthesized by the fermentation of glucose obtained from the hydrolysis of starch. Even though there are lots of starch sources in Sri Lanka, study on LA extraction from corn starch is lacking. In present study, glucose was obtained from powdered corn kernels via hydrolysis by α-amylase. The hydrolysis was optimized by varying the stirring time (0.5-2.0 hrs.), temperature (27-57 °C) and corn starch concentration (0.25-1% w v-1). The glucose concentration after the hydrolysis was measured by 3, 5-Dinitrosalicylic acid method. The highest glucose concentration was obtained having 0.75% of corn starch solution at 47 °C and 1.5 hrs. stirring time. Then glucose was fermented (37 °C, 0.5-4.5 days) using Streptococcus thermophilus which is a LA bacterium. Samples taken from fermenter at different time intervals were analyzed for LA by UV visible spectrophotometer at 390 nm after developing the yellow color ferric lactate using FeCl3. The highest concentration of LA was obtained after 4 days of fermentation. Fermentation broth was centrifuged, and crude LA was purified using fractional distillation. The purity of the samples was investigated by FTIR spectroscopy. FTIR results of the purified product were agreed well with that of commercial LA. The characteristic peaks of LA were observed at 1722 cm–1 (C=O stretching), 2600–3200 cm-1 (O–H stretching), 1200– 950 cm−1 (C–C and C–O stretching) and 1200 cm-1 (C-H, C-O, and CH3 vibrations). In conclusion, LA was successfully extracted from Sri Lankan grown corn starch and the present method can be developed to produce LA in bulk quantities ultimately converting the LA into PLA.
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    Fungi in Sri Lankan Ecosystems: A Review of Current Knowledge, and Future Directions
    (Uva Wellassa University of Sri Lanka, 2021) Chandrathilake, A.G.N.M.; Ediriweera, E.P.S.K.; Singhalage, I.D.
    Fungi are an incredible source that can be used for the economic development of developing countries like Sri Lanka to achieve the United Nation's Sustainable Development Goals. The utilization of fungal resources towards economic development is considerably less because fungi are one of the groups that have been poorly investigated in Sri Lanka. This study aimed to critically evaluate the knowledge gap of fungal studies in Sri Lanka by considering the status of the South Asian region, the Asian region and the World. Therefore, local, regional and world literature related to fungal studies were collected. Data collection was done by using online available sources, visiting resource places as well as contacting resource persons. Then, the collected 1142 different types of literature documents were referred and classified mainly under basic fungal biological studies and applied fungal studies by considering the areas of studies available. After that, necessary information from the literature of each category was extracted and analyzed the gap concerning the world status through the literature to identify new research opportunities of mycology in Sri Lanka. At present global mycology is in the status of identifying and introducing new fungal divisions, classes, orders and new families by using molecular techniques such as quantitative PCR techniques, DNA barcoding, probe development and effective amplification techniques. The global estimate is about 2.2 to 3.8 million fungal species and out of those 144,000 species have been already named and classified. Thus, over 93% of species are currently not explored and are unknown to science. Currently, the Asian region is the pioneer for fungal discovery. In 2017, 35% of new fungal species were discovered in the Asian region which is the highest fungal discovery percentage among all the regions in the World. Findings of this study showed that Sri Lanka is far behind in the World and the Asian region as approximately 3000 fungal species have been identified out of estimated 25,000 native fungal species. The highest knowledge gap is exhibited in the area of fungal taxonomic research in Sri Lanka. There is a great possibility of implementing fungal research in Sri Lanka. However, collaborative efforts of scientists of different fields are needed with financial support to reveal the fungal resources to be utilized in the economic development of the Island. Keywords: Mycological studies; Fungal diversity; Sri Lanka; Knowledge gap
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    Modification of Nutrient Agar Medium to Culture Un-culturable Bacterial Strains Living in Unsanitary Landfills
    (Uva Wellassa University of Sri Lanka, 2020) Devika, K.K.C.; Singhalage, I.D.; Seneviratne, G.
    The decomposition of municipal solid waste is mediated by native microorganisms and it is essential to estimate the participating microorganisms to accelerate the decomposition of waste material. However, 99% of bacterial species remain unculturable in the standard Nutrient Agar (NA) medium. This research was focused on the modification of the NA medium to mimic the composition of the natural substrate where they live. Conventional NA medium was modified by adding separately 40% (M1), 32% (M2), 24% (M3), 16% (M4), 8% (M5) (v/v) of soil extracts obtained from the dumpsite. The Conventional NA medium was the control. Random soil samples were collected from the garbage dump and bacterial species were isolated in each modified medium. The isolated bacterial cultures were air-dried under aseptic conditions and powdered. To characterize them, Fourier Transform Infrared (FTIR) spectra were recorded for all bacterial samples in the 500 - 4000 cm-1 region at 4 cm-1 resolution by scanning 120 times. The average of the absorbance of each FTIR spectrum was used as variables of the distance matrix of the cluster analysis (Minitab 19). A total of 103 bacterial strains were isolated and 9 bacteria samples showed a similarity level of more than 98%. The 20, 14, 16, 16, 18, and 19 bacteria species were isolated from the modified media M1, M2, M3, M4, M5, and the control, respectively. According to the cluster analysis, six clusters were obtained. Cluster 1 was the largest and it consisted of 45.63% of the total bacterial isolates from M1, M2, and the control. Cluster 2 consisted of 30.10% of total isolates from M4-M5. All the other isolates were clustered in clusters 3, 4, and 5. The separate clustering of the isolated bacteria in the modified media showed dissimilarity among them, thus indicating the potential of the soil extracts to modify NA to culture un-culturable bacterial strains living in unsanitary landfills. Keywords: Unculturable bacteria, Soil extracts, FTIR
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    Pectinase and Cellulase Activity of Bacterial Strains Isolated from Unsanitary Landfills
    (Uva Wellassa University of Sri Lanka, 2020) Weerawardana, R.D.T.; Singhalage, I.D.
    Cellulase and pectinase producing bacteria can bring a scientific solution to overcome the municipal solid waste problem by introducing them as organic waste decomposers. Such bacterial species can use to reduce the cost of industrial enzyme production. The study aimed to isolate the bacterial strains with good cellulase and pectinase producing capability from unsanitary landfill soil to be utilized in organic waste degradation and industrial enzyme production in the future. All 21 bacterial strains were isolated in Nutrient Agar plates using serial dilution, spread plate, and streak plate methods. Morphological characteristics of bacterial colonies were noted. Well, diffusion assay was used to screen the cellulase and pectinase activity using carboxymethylcellulose (CMC) and Pectinase Screening Agar Medium (PSAM) respectively. The positive results were evidenced by clear inhibition zones in CMC and PSAM. The diameters of the clear zones were measured. There were three replicates for each bacterial culture. The experimental design was Complete Randomized Design. Data were analyzed by ANOVA in Minitab 16. Out of 21 isolates, 62% presented at least one considerable enzymatic activity. Zones of hydrolysis produced by the bacterial strains were ranged from 1.4 - 3.2 cm for cellulase while it was 1.0 – 5.1 cm for pectinase. The bacterial culture B14 showed the significant (p ≤ 0.05) halo zone diameter in the CMC medium over the tested species by proving the highest cellulase activity. The most potent pectinase producers were found to be the isolate B1 and B6 because such cultures showed the significant (p ≤ 0.05) halo zone diameter over the other species in PSAM. Based on morphology B1 was a bacillus in shape whereas B6 and B14 were coccus in shape. As per the results, it can be concluded that unsanitary landfill soil is inhabited by cellulose and pectin degrading bacteria, hence can be utilized in enzyme production and organic waste treatments. . Keywords: Cellulase, Pectinase, Soil bacteria
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    Utilization of Lycopene from Tomato (Lycopersicon esculentum L.) Peel as Natural Antioxidant and Colorant in Stirred Yoghurt
    (Uva Wellassa University of Sri Lanka, 2018) Meegahawaththa, W.K.; Mudannayake, D.C.; Singhalage, I.D.
    Tomato peel is a good source of lycopene which can be used as a natural antioxidant agent and colorant in foods. This study investigated use of Tomato Peel Powder (TPP) as an antioxidant agent and a colorant in stirred yoghurt. Tomatoes were washed, immersed in boiling water (1-2 min) and hand peeled. Tomato peel was lyophilized, pulverized and analyzed for Radical Scavenging Activity (RSA) using DPPH (2, 2-diphenyl-1-picylhydrazyl) method and Total Phenolic Content (TPC) using Folin-ciocalteu reagent assay. Total Carotenoid Yield (TCY), expressed as lycopene in TPP was measured. FTIR (Fourier Transform Infra-Red) and UV-Vis spectrum analysis were done for TPP comparing with extracted lycopene and commercial lycopene. Two batches of stirred yoghurts were prepared by adding lyophilized TPP at level of 0%, 2%, 4%, 6% and 8% (w/w) Before Incubation (BI) and After Incubation (AI). The physiochemical properties, microbial and sensory analysis were conducted to determine the quality of stirred yoghurts. RSA and color of all ten stirred yoghurt samples were investigated at 7 days interval at refrigerated storage for 21 days using DPPH method and colorimeter, respectively. RSA (%) and TPC of TPP were 50.05±0.66% and 0.38±0.01 mg GAE extract, respectively. TCY of the TPP was 71.42±0.1 mg kg-1 . FTIR and UV-Vis spectrum data confirmed the presence of lycopene in TPP. Significantly higher (P < 0.05) overall acceptability was shown by the stirred yoghurt contained (2%) TPP. The highest RSA was shown by the sample contained 8% TPP, AI (23.07±0.04%) while, the lowest RSA was shown by the control BI (1.58±0.03%). TPP (8%) added sample showed the highest color value for redness (18.83±0.37). Results revealed that TPP can be successfully incorporated into stirred yoghurt as a natural antioxidant agent and a colorant.