Browsing by Author "Henegamage, A.P."

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    Biocoagulation and Its Potential Application for Graphite Bioprocessing
    (Uva Wellassa University of Sri Lanka, 2013) Jayarathna, S.P.B.L.; Peries, C.M.; Henegamage, A.P.
    Sri Lanka is famous for Graphite industry since ancient times around the world. There are three major Graphite mines which are located in Kahatagaha, Bogala and Ragedara. Vein type graphite deposits in Sri Lanka are considered as a unique occurrence of graphite because of its high purity, extensive mineralization and restricted occurrence. Graphite with 95-99% of carbon and gangue minerals such as pyrite, chalcopyrite, calcite, biotite and feldspars are found in each structural type depending on the mode of occurrences and nature of graphite vein (Amarweeraet al., 2013). Hence, removal of impurities from the graphite can increase the economic value of graphite. Flotation cell is common in Graphite industry to upgrade its carbon grade by removing impurities and it can be used to upgrade over 80 % Graphite in Sri Lanka However, efficiency of the flotation cell separation is not effective for Graphite with small particle sizes (Karr et al., 1990). Biocoagulation is the promising method, practiced in all over the world for sorting of small sized mineral particles with the use of microorganisms (Kuyumcuet al., 2009). Therefore, this study is focused to increase the carbon recovery in Graphite through the separation of fine particles using the biocoagulation with microorganisms. Methodology Three different particle sizes (40µm, 53µm and 72µm) of graphite samples were obtained from Bogala and Kahatagaha mines. Isolation of fungi was carried out from the obtained samples using dilution plate techniques with Potato Dextrose Agar (PDA) medium. Pure cultures of the isolated fungi were obtained using single spore isolation technique with the same medium. Isolated pure fungi cultures were inoculated in to 20 ml of Potato Dextrose Broth (PDB) and incubated for 48 hours at 30 C. Then the pH values of the each fungi broth cultures were measured separately. Two grams of each different graphite samples with different particle sizes were mixed with the incubated PDB and kept with continuous mixing for the coagulation. After four days of incubation, the number of coagulates in each broth cultures was counted using the light microscope and the fungal broth culture (F3) which was given the highest coagulates number was selected for the further processing. In order to determine the carbon grade of the sample, coagulates of the selected broth culture were carefully separated out from the broth medium and washed with distilled water for three times. Then the particles with the coagulates were kept in a muffle furnace at 500 C for two hours in order to remove microbial biomass from graphite particles followed by keeping the samples again in muffle furnace at 960 C for further digestion. Initial and the final weights of the sample were measured to calculate the percentage of carbon recovery. Three replicates were maintained for each treatment and data were analyzed using ANOVA with the confidence level of 95% using MINITAB statistical software.
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    Development of Bioethanol from Water Hyacinth (Eichhornia crassipes) Using Cellulose Degrading Microbial Biofilm
    (Uva Wellassa University of Sri Lanka, 2019-02) Thakshika, G.; Peries, C.M.; Henegamage, A.P.
    Water hyacinth (Eichhornia crassipes), a persistent and invasive weed found in Sri Lanka that creates numerous problems to aquatic ecosystems. However, it is a promising candidate for bioethanol production due to its abundant availability, low cost and high yield. Currently, usage of lignocellulosic biomass is sustainable alternative to support the global demand for fossil fuels. Still, the conversion of cellulosic material to fermentable sugar is a rate-limiting step due to its highly resistant nature. Therefore, this study was focused to evaluate the efficiency of production of bioethanol from water hyacinth using cellulose degrading microbial biofilms. Microorganisms were isolated form soil sample obtained from a coir retting land in Kurunegala district and were inoculated on Carboxy Methyl Cellulose Agar to screen the most effective cellulolytic fungi and bacteria. One fungal (F2) and two bacterial isolates (B1, B3) were selected based on the cellulolytic activity. Biofilms were developed from the selected fungi and bacteria based on the high cellulolytic activity. The efficiency of the cellulolytic activity by the biofilms were evaluated using 3, 5 DNS assay. The selected biofilms were combined with 2 g of acid pre-treated water hyacinth and were kept nine days at room temperature for fermentation. Saccharomyces cerevisae served as the control. Bioethanol production was estimated by dichromate method and confirmed by FTIR analysis. Out of selected biofilms, F2B3 biofilm showed significantly higher bioethanol production (62.85 ppm, P< 0.05) than Saccharomyces cerevisae (59.81 ppm) after nine days’ of fermentation. Further, the yield of bioethanol obtained by F2B3 biofilm and Saccharomyces cerevisae from water hyacinth were 0.037% and 0.032% respectively. Therefore, there is a prospect to enhance the bioethanol production from water hyacinth using the effective biofilms.
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    The Effect of Selected Sri Lankan Herbal Plant Crude Extracts Against Spodoptera frugiperda (Fall Armyworm)
    (Uva Wellassa University of Sri Lanka, 2020) Ranaweera, M.N.; Henegamage, A.P.; Prematilake, M.M.S.N.; Peris, C.M.
    The fall armyworm (FAW), Spodoptera frugiperda is a recent invasive pest that has successfully established in Sri Lanka where it continues to disrupt agriculture, particularly corn production. Management of fall armyworm using agrochemicals has led to the development of resistance against many insecticides and the accumulation of toxic residues on agricultural products. Therefore, the utilization of plant extracts which are wealthy in bioactive compounds for the control fall armyworm has become a developing pattern. This study was undertaken to screen the effectiveness of Adathoda vassica, Dathura metal, and Tagetes erecta crude extracts against fall armyworm. Shade dried leaves were used for the extraction which was done by the Soxhlet method using methanol and ethyl acetate as solvents. Bioefficacy of crude extracts was studied against third instar larvae of S. frugiperda using 4000, 2000 and 1000 ppm concentrations to test the contact toxicity by topical application method, antifeedant activity by leaf disc no choice assay and repellency effect from the dual choice method. Commercially available insecticide, collagen was used as a positive control. The crude extracts from T. erecta (LD50 - 186.63µg/g) and D. metel (LD50 - 256.44µg/g) showed significantly (p < 0.05) high mortality (100%) rate within twelve hours even compared with the positive control. The results revealed that the methanolic extract of T. erecta showed the highest significant (p < 0.05) antifeedant activity (92.09%) at 4000 ppm compared with other plant extracts. All plant extracts provoked a notable decrease in feeding with the increment of their concentration. Methanolic extract of T. erecta showed the highest significant repellency (66.65%). Therefore, it can be concluded that methanolic extracts of D. metel and T. erecta have the power of damaging fall armyworm and are suitable candidates for the development of bio-insecticide for the local use. Keywords: Fall armyworm, Adathoda vassica, Dathura metel, Tagetes erecta
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    Effect of α-Pinene on the Soil Bacterial and Fungal Population and Soil Organic Carbon in Eucalyptus Plantations
    (Uva Wellassa University of Sri Lanka, 2019-02) Dahanayake, P.M.; Premetilake, M.M.S.N.; Henegamage, A.P.; Herath, H.M.S.K.
    Nutrient cycling is essential for the stability of an ecosystem where soil microorganisms play a significant role. Some allelochemicals such as α-pinene produced by certain plant species may suppress the activity of these microorganisms. Eucalyptus, which is a popular plantation species in Sri Lanka, is known to emit α-pinene. However, its effect on soil microorganisms and soil fertility is not well known. The present study investigated the relationship between α-pinene content, soil microorganisms and soil organic carbon content in 7-year-old Eucalyptus grandis and Eucalyptus torelliana plantations. As the control plantation, an adjacent Patna grassland (previous land-use before afforestation) was used. Three subplots (20 × 20 m) were established within each site and soil was sampled up to 15 cm depth. Soil organic carbon content was measured according to the Walkley-Black method. Following a serial dilution, bacteria and fungi were cultured and CFU mL-1 was calculated. The α-pinene in soil samples was extracted using petroleum ether and was analyzed using GC-MS. According to the results, there was a significant (P<0.05) variation between organic carbon, α-pinene content and bacteria quantity between the plantations and the adjacent grasslands. However, there was no significant (P>0.05) variation in fungi quantity. The highest organic carbon content was observed in E. torelliana plantation (2.08% ±0.3), however; the highest α-pinene content was found under E. grandis plantation (0.14% ± 0.09). Interestingly, the highest bacterial count was recorded under E. grandis plantation (3.0 x 105 CFU mL-1) while the highest fungi count was recorded in grassland. There were no significant (P>0.05) correlations between the soil α-pinene content, soil bacterial and fungal count fungal and the organic carbon. There is no significant effect (P>0.05) of α-pinene content on the bacterial and fungal counts and organic carbon in young E. grandis and E. torelliana plantations.
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    Production of bioethanol from vegetable waste using a small scale reactor as an environment management system
    (Uva Wellassa University of Sri Lanka, 2013) Perera, K.M.K.; Henegamage, A.P.; Ekanayeka, R.M.C.T.B.
    It is very much evident that the combustion of the fossil fuels at the current rate would contribute to the environmental crisis globally (Chandel et al., 2007). Studies have revealed that there are attempts to develop alternative source of energy so as to conserve the dwindling reserves of crude oil and fossil fuels (Akpan et al., 2005;Taherzadeh and Karimi, 2008; Hossain and Fazliny, 2010).Bioethanol is considered as one of the best alternative energy sources since it is an environmental friendly and lower pollutant energy source which can be produced from the lignocelluloses out of the waste vegetables. Ethanol can be produced by fermentation of any organic materials rich in carbohydrate through microbial activity. Yeast is one of the most important microorganisms in the production of ethanol through the fermentation. Previous study has proven that the use of Saccharomyces cerevisiaes train could optimize the fermentation performance using waste materials containing sugar and starch (Arumugam and Manikandan, 2011).The utilization of the waste feedstock for biofuel production does not disturb the food chain as it is a waste-to- energy concept based. The massive amount of agricultural waste (fruit and vegetables) generation necessitates the need of technology development to derive economic benefit by turning this waste into a useful product. For instance, one third of the agricultural products (vegetables and fruits) in Sri Lankan market system end in waste due to poor handling and storage practices. (Weerahewa et al., 2004). Therefore, this study was mainly focused on the production of bioethanol from the rotten vegetables removed from the Sri Lankan market as an alternative energy source. Further, the fabrication of a low cost stirring batch type bioreactor system was highlighted to improve the efficiency of bioethanol production based on the requirement of environmental waste management system. Methodology In order to facilitate the bioethanol production from rotten vegetables, a portable small scale low cost bioreactor system was fabricated. The overall implementation and scaling up of the system was based on the waste materials mostly in order to eliminate the unnecessary costs. Further, a low cost solar dryer was fabricated to minimize the electrical energy consumption and to maximize drying process. Approximately 40-45kgof agriculture waste materials which were not suitable for human consumption, were collected from the local vegetable markets. The selected vegetable waste were washed and cut into small pieces where they were subjected to sun dry for seven days under hot sun using the fabricated solar dryer. Dried waste materials were subjected for acid pre-treatment using Conc.H2SO4 (aq) 60 minutes of boiling at 120°C followed by adding distilled water and Saccharomyces cerevisiaeaccording to a pre-determined ratio. Different shaking hour combinations and different fermentation days were evaluated in order to obtain the optimum requirements. The pretreated mixtures with different shaking hours were filtered in to different schott bottles separately and measured pH and Total Soluble Solids (TSS). Bioethanol concentration was estimated according to the method proposed by Williams and Darwin (1950). Then the statistically significant shaking hour and number of fermentation dayscombination was employed in to the fabricated bio reactor modal. Bioethanol concentration, pH and TSS values of the fermented mixture in the bio reactor was measured while maintaining the all other parameters constant as the laboratory experiment procedure.Chromic acid oxidation test,Ritter test and Lucas tests were carried out with respect to narrow down the justification of ethanol been produced (Pasto et al, 1992).AAS (Atomic Absorption Spectrometer) analysis was carried out for further identification of the elements in the produced raw bioethanol. The statistical analysis was carried out according to two factor factorial in Complete Randomized Design (CRD) experimental design using MINITAB 15.0 statistical package.
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    Screening of Alpha Amylase Inhibitory Activity and Antioxidant Activity of Selected Sri Lankan Medicinal Plants
    (Uva Wellassa University of Sri Lanka, 2019-02) Somarathna, K.T.A.G.; Henegamage, A.P.; Alakolanga, A.G.A.W.
    Diabetes mellitus (DM) is one of the global health emergencies that characterized by high blood glucose levels. Adding antioxidants to the therapy of DM is intended to reduce complications caused by oxidative stress. In the treatment of diabetes, alpha-amylase inhibitory activity and antioxidant activity are playing a significant role. The medicinal plants grown in Sri Lanka have been proven to retard the absorption of glucose by inhibiting the carbohydrate hydrolyzing enzymes, such as pancreatic amylase. Thus, this study was conducted to investigate alpha amylase inhibitory activity and antioxidant activity of Vernonia zeylanica (Pupula), Leucas zeylanica (Gatathumba), Trichosanthes integrifolia (Dummella) and Crateva adansonii (Lunuwarana). Aerial parts of the selected plants were air dried and extracts were obtained using 80% acetone with 20% water. The alpha amylase inhibitory activity was performed using 3,5-dinitrosalicylic acid (DNSA) method and starch iodine method and the antioxidant activity was measured using 2,2-diphenyl-1-picrylhydrazyl radical DPPH assay and ABTS radical cation scavenging assay. In DNSA assay, Vernonia zeylanica extraction showed the highest significant mean inhibition (29.8 %, p < 0.05) at 1000 mg l-1 concentration. Out of all plant extracts, the highest significant mean inhibition (51.25 %, p < 0.05) for the starch iodine assay was shown by Crateva adansonii at 1000 mg l-1 concentration. Extracts from Vernonia zeylanica showed the lowest IC50 value (less than 10 mg l-1)for the DPPH assay of the antioxidant activity compared with the IC50 value of the standard (ascorbic acid, 7.24 mg l-1). The best IC50 was observed from Leucas zeylanica for the ABTS assay with the value of 100.7 mg l-1 with respect to ascorbic acid (4.75 mg l-1). It was identified that out of all selected plants, Vernonia zeylanica possess both alpha amylase inhibitory activity and antioxidant activity.