Enhancement of solubility of Eppawala Rock Phosphate through Bioleaching
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Date
2015
Journal Title
Journal ISSN
Volume Title
Publisher
Uva Wellassa University of Sri Lanka
Abstract
Phosphorus (P) plays an indispensable biochemical role in photosynthesis, respiration, cell
division and several other processes in the living plant (Grover, 2003). An inadequate supply of
phosphorus in the early stages of plant growth reduces most of these physiological functions and
ultimately reduces the crop productivity. Therefore, external applications of P fertilizers is
necessary in terms of better crop production. Locally available P resources like Eppawala Rock
Phosphate (ERP) deposits are now highly concerned due to the environmental effects and the high
cost of imported P fertilizers. However, the ERP is considered as less applicable local P resource
for short term cultivations due to the low solubility. Although chemical treatments are highly
available to solubilize ERP, the cost of application is fairly high. In that sense, the inoculation of
naturally existing P-solubilizing microorganisms is considered as a promising technique to
solubilize P sources due to the low application cost and giving a thrust to economic development
without disturbing ecological balance (Reyes et al., 2002). Thus, this study was focused on
screening the P solubilizing microorganisms (PSM) from ERP deposit and apply them to enhance
the solubility of ERP and High-Grade Eppawala Rock Phosphate (HERP).
Methodology
Powdered Rock Phosphate samples were collected from the rock phosphate stockpile of phosphate
mine of Lanka Phosphate Limited, Eppawala. Microbial isolation were performed from the
obtained Phosphate samples using standard microbiological techniques. Isolated microbial strains
were inoculated on PVK medium, a selective medium to screen PSM. Thereafter, screened
microbial strains were inoculated in PVK broth media containing either ERP or HERP separately.
P content in each sample was determined using UV spectrophotometric method after 1 , 2
and 7
Result and Discussion
Four bacterial strains and four fungal strains were initially isolated using the rock phosphate
samples obtained from phosphate mine of Lanka Phosphate Limited, Eppawala, Sri Lanka. Out
of them, two bacterial strains (B1 and B2) were selected as potential phosphate solubilizers based
on the development of clear halo zone on PVK agar medium due to the P solubilization in the
surrounding medium (Fig. 1 a and b).
Description
Keywords
Mineral Sciences, Materials Sciences, Mineral, Chemistry, Eppawala Rock Phosphate