초록
<P><B>Abstract</B></P><P><B>BACKGROUND:</B> Poly(3‐hydroxybutyrate‐<I>co</I>‐3‐hydroxyvalerate) [P(3HB‐<I>co</I>‐3HV)] co‐polymer has immense potential in the field of environmental and biomedical sciences as biodegradable and biocompatible material. The present study examines a filamentous N<SUB>2</SUB>‐fixing cyanobacterium, <I>Nostoc muscorum</I> Agardh as a potent feedstock for P(3HB‐<I>co</I>‐3HV) co‐polymer production and characterization of co‐polymer film for commercial applications.</P><P><B>RESULTS:</B> Under photoautotrophic growth conditions, <I>N. muscorum</I> Agardh accumulated the homopolymer of poly‐β‐hydroxybutyrate (PHB), whereas synthesis of P(3HB‐<I>co</I>‐3HV) co‐polymer was detected under propionate‐ and valerate‐supplemented conditions. Exogenous carbons such as acetate, fructose and glucose supplementation with propionate/valerate was found highly stimulatory for the co‐polymer accumulation; the content reached 58–60% of dry cell weight (dcw) under P‐/N‐deficiencies with 0.4% acetate + 0.4% valerate supplementation, the highest value reported so far for P(3HB‐<I>co</I>‐3HV) co‐polymer‐producing cyanobacterial species. The material properties of the films were studied by mechanical tests, surface analysis and differential scanning calorimetry (DSC).</P><P><B>CONCLUSION:</B> <I>N. muscorum</I> Agardh, a photoautotrophic N<SUB>2</SUB>‐fixing cyanobacterium, emerged as a potent host for production of P(3HB‐<I>co</I>‐3HV) co‐polymer with polymer content 60% of dry cell weight. The material properties of the films were found to be comparable with that of the commercial polymer, thus advocating its potential applications in various fields. Copyright © 2012 Society of Chemical Industry</P>