微生物および生化学技術ジャーナル

概要

Polyhydroxy alkanoates Production by Newly Isolated Bacteria Serratia ureilytica Using Volatile Fatty Acids as Substrate: Bio-Electro Kinetic Analysis

M Venkateswar Reddy and S Venkata Mohan

Polyhydroxy alkanoates (PHAs) show physical and material properties similar to conventional plastics, so these are considered as an alternative to non-biodegradable plastics. In the present study, PHA production using Serratia ureilytica, a newly isolated bacterial strain from PHA producing bioreactor was investigated using volatile fatty acids as substrate at four different organic loading rates (OLRs, OLR1-OLR4). Among four OLRs, S. ureilytica showed highest PHA production (51% dry cell weight) with OLR2 at 24 h, but it showed highest substrate removal with OLR1 (84%). PHA composition showed the presence of co-polymer, poly (3hydroxybutyrate-co-3hydroxyvalerate), P(3HBco- 3HV). In cyclic voltammetry analysis the activity of specific redox mediators was observed at 24 h and 36 h of PHA production process. Lower Tafel slopes in bio-electrokinetic analysis also supported the decrease in electron losses during PHA synthesis. Bioprocess evaluation and enzymatic activities showed good correlation with PHA production.