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Enhanced synthesis of polyhydroxyalkanoates and -amylase by Bacillus sp.

Irfan Ali, K. (2009) Enhanced synthesis of polyhydroxyalkanoates and -amylase by Bacillus sp. [Student Project Report]

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Abstract

This Dissertation / Report is the outcome of investigation carried out by the creator(s) / author(s) at the department/division of Central Food Technological Research Institute (CFTRI), Mysore mentioned below in this page.

Item Type: Student Project Report
Additional Information: The increase in the demand of plastic has accelerated in the production of the petrochemical plastics, the plastics is being used in various industries, but the increasing demand of plastic has correlated the increase in environmental pollution, which has become a threat to the life and atmosphere. Various steps have been taken to overcome this problem. Among which biodegradable plastics has come as a boon to the life and atmosphere. Lots of research work is being carried out to produce good yield and quality biodegradable plastics. The bioplastics is being used in various parts of the world, but due to its high production cost the demand is being decreased commercially. The present research work has been carried to lower the production cost by using the cheaper sources of carbon such as agro-industrial wastes, the work was carried out to enhance the production of bioplastics by using cheaper parameters as discussed further. Bioplastics are nothing but polyhydroxyalkanoates (PHA) produced by various microorganisms. The microorganisms produces PHA under nutritional depletion conditions, which occurs under limiting supplement of N, P, S, O and Mg, but with excess supplement of carbon sources. Polyhydroxyalkanoates are the polyesters of 3-. 4-, 5-, 6- hydroxyalkanoic acids synthesized by numerous bacteria as intracellular carbon and energy storage compound, in the present work Bacillus spp were used as maintained in Food Microbiology dept, CFTRI, Mysore. Optimization of the production medium was carried out. In this experimentation various nitrogen and cheaper carbon sources were tested to enhance the PHA production, several inorganic and organic nitrogen sources were tested, among which ammonium acetate as inorganic and yeast extract as organic nitrogen sources were found to produce good amount of PHA (1-2 g/L) and amylase (10-50 U/ml) yield, hence were selected as nitrogen sources to optimize the medium. Various starches were used as cheaper carbon 69 sources as mentioned, good amount of PHA (2 g/L) and amylase (67 U/ml) yield were found with potato starch, and hence potato starch was selected as carbon source. After selecting the optimized carbon and nitrogen source, the medium was supplemented with different concentration 1%, 2.5% and 5% of rice bran and wheat bran hydrolysate an agro industrial waste, with this supplementation there was a significant increase in the PHA yield of 5 g/L and amylase yield was found to be constant with 40-50 U/ml. With the above selected conditions Response surface Methodology (RSM) was carried out selecting 5 different variables – rice bran hydrolysate, ammonium acetate, potato starch, Na2HPO4 and KH2PO4 based on there, 33 different combinations were designed, and the obtained results were tested with biostatistical analysis by using the software Quattro pro software package (Quattro pro, version 4.0, Borland international Inc. USA). With this the coefficient were studied, where optimal level of rice bran (100 g/L), ammonium acetate (3.5 g/L), potato starch (50 g/L), Na2HPO4 (0.5 g/L) and KH2PO4 (0.5 g/L) were found to produce maximum yield of biomass with good amount of PHA content. From the above experimentation and RSM analysis, it was concluded that the agro industrial by products like rice bran and cheaper carbon sources like potato starch were found to produce good PHA and amylase yield, and RSM study was effective for designing optimum combination and PHA production.
Uncontrolled Keywords: polyhydroxyalkanoates; Biodegradable plastics; microbial bioplastics;
Subjects: 500 Natural Sciences and Mathematics > 04 Chemistry and Allied Sciences > 27 Polymer Chemistry
500 Natural Sciences and Mathematics > 07 Life Sciences > 04 Microbiology > 02 Bacteriology
Divisions: Food Microbiology
Depositing User: Food Sci. & Technol. Information Services
Date Deposited: 16 Jun 2010 04:43
Last Modified: 28 Dec 2011 10:14
URI: http://ir.cftri.com/id/eprint/9416

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