Production and characterization of polyhydroxyalkanoates synthesized by E. coli Isolated from sludge soil

Abstract

The petrochemical-based non-degradative polymers are causing severe environmental pollution that resulting in acute or chronic toxicity in living organisms. Hence emerging of biological polymers is significant to replace traditional polymers. Therefore, the present study aimed to isolate efficient PHAs producing bacteria from municipal sludge soil, characterize the biopolymers by FT-IR and 1H NMR and optimize growth conditions for mass production of PHAs. 10 predominant bacteria cultures were isolated from sludge soil, out of 10 single isolates has the potential to produce PHAs, and it was characterized and identified asE. coli.The PHAs produced byE. coliwas characterized by FT-IR and NMR analysis. The results show that components of PHAs such as carbonylhydroxybutyrate, hydroxyoctaoate (HO), medium chain length polyhydroxyalkanoates, and hydroxydecanoate showed their strong characteristic band at 1631 cm−1, 1548 cm−1, 1409 cm-1 respectively in the extracted sample. Further, the NMR reports show that the presence of interconnection functional groups like HC = CH bond at 3.363 ppm, CH2O–COOH bond at 2.548 ppm. The optimal growth conditions forE. coliwere optimized. Briefly, 9% of inoculum, sago molasses (as suitable carbon source), 35 °C, pH 7.5 48hrs of incubation, in which theE. coliproduce 27.1 g/L of PHAs extracted from 33.26 g/L of biomass and in percentage it was calculated as 81.47%. The entire results determine that the E. colienumerated from sludge soil has the efficiency to produce PHAs, hence it possible for commercialization by using cheap carbon sources.