Unveiling Polyhydroxyalkanoates Producing Bacteria Isolated from Mangalore Environment: An Unearthing Study

Abstract

Certain microorganisms in nature produce intracellular linear bio-esters called Polyhydroxyalkanoates (PHA), under limited nutrient condition in the presence of excess carbon. PHAs are environment friendly macromolecules exhibit properties similar to petrochemical plastics. In the present study a total of 30 soil samples were collected from different sites and screened for PHA producing bacteria. Among them 30 isolates were showed positive for PHA production by preliminary screening methods. Growing conditions for the synthesis of PHA were optimized. The recovered bacteria were able to produce PHA after 72 hours of incubation at 30°C, pH 7, with 10% inoculum. The positive PHA-producing bacterial strains were identified using 16S rRNA sequencing. The PHA accumulation was up to 59% by PHAD13 isolate, Bacillus subtilis isolated from the petrol bunk soil, NG6 isolate, Klebsiella spp. isolated from garden soil showed 33.5% and the maximum PHA accumulation was about 35.1% by NS1, Bacillus spp. isolated from sewage soil. Intracellular accumulation of PHA for the highest PHA producing isolate PHAD13 was analysed by Transmission electron microscope further characterized using FT-IR. All these diverse sources (Petrol bunk soil, Sewage soil, Garden soil) were shown to be rich sources variety of bacterial species with the ability to produce PHA thereby rendering the biodegradation.