Variation analysis of bacterial polyhydroxyalkanoates production using saturated and unsaturated hydrocarbons

ABSTRACT Polyhydroxyalkanoates (PHA) are efficient, renewable and environment friendly polymeric esters. These polymers are synthesized by a variety of microbes under stress conditions. This study was carried out to check the suitability of waste frying oil in comparison to other oils for economical bioplastic production. Six bacterial strains were isolated and identified as Bacillus cereus (KF270349), Klebsiella pneumoniae (KF270350), Bacillus subtilis (KF270351), Brevibacterium halotolerance (KF270352), Pseudomonas aeruginosa (KF270353), and Stenotrophomonas rhizoposid (KF270354) by ribotyping. All strains were PHA producers so were selected for PHA synthesis using four different carbon sources, i.e., waste frying oil, canola oil, diesel and glucose. Extraction of PHA was carried out using sodium hypochlorite method and maximum amount was detected after 72 h in all cases. P. aeruginosa led to maximum PHA production after 72 h at 37 °C and 100 rpm using waste frying oil that was 53.2% PHA in comparison with glucose 37.8% and cooking oil 34.4%. B. cereus produced 40% PHA using glucose as carbon source which was high when compared against other strains. A significantly lesser amount of PHA was recorded with diesel as a carbon source for all strains. Sharp Infrared peaks around 1740-1750 cm-1 were present in Fourier Transform Infrared spectra that correspond to exact position for PHA. The use of waste oils and production of poly-3hydroxybutyrate-co-3hydroxyvalerate (3HB-co-3HV) by strains used in this study is a good aspect to consider for future prospects as this type of polymer has better properties as compared to PHBs.

Properties of a biosurfactant produced by Bacillus pumilus using vinasse and waste frying oil as alternative carbon sources

Biosurfactants are chemical molecules produced by the microorganisms with potential for application in various industrial and environmental sectors. The production parameters and the physicochemical properties of a biosurfactant synthesized by Bacillus pumilus using different concentrations of vinasse and waste frying oil as alternative carbon sources were analyzed. The microorganism was able to grow and produce a biosurfactant using both the residues. The surface tension was reduced up to 45 mN/m and the maximum production of crude biosurfactant was 27.7 and 5.7 g/l for vinasse and waste frying oil, respectively, in concentration of 5%. The critical micelle concentration (CMC) results of 1.5 and 0.2 g/l showed the efficiency of the biosurfactant produced on both the substrates. The results showed that the alternative substrates could be used for the production of an efficient biosurfactant by B. pumilus. These properties have potential for industrial and environmental applications.