(335c) Biosynthesis of Polyhydroxybutyrate By Thermotolerant Chelatococcus Daeguensis Strain TAD1 At Elevated Temperatures: A Potential Low-Cost Way for Large-Scale Production

Biosynthesis of polyhydroxybutyrate by thermotolerant Chelatococcus daeguensis strain TAD1 at elevated temperatures: A potential low-cost way for large-scale production

Shaobin Huang^a,b,c,*, Fuqian Xu^a,c, Bichun Huang^a, Ruimin Huang^a, Yongwen Ma^c,d

^aCollege of Environment and Energy, South China University of Technology, Higher Education Mega Center, Guangzhou 510006, P.R. China

^bState Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, P.R. China

* Corresponding author. Tel/Fax: 86-020-39380587  Email: chshuang@scut.edu.cn

Abstract: This study set out to investigate the polyhydroxybutyrate (PHB) accumulation properties of a newly isolated thermophilic denitrifier-Chelatococcus daeguensis TAD1. TAD1 could accumulate PHB effectively at a broad range of temperatures (from 35 ^oC to 55 ^oC), and the highest cell density and PHB-accumulation were 3.6 g cell dry weight (CDW) per liter and 83.6% of CDW (w/w) at 45 ^oC, respectively. Although lower nitrogen concentrations showed higher PHB accumulation, the optimal PHB production of TAD1 was acquired at a  medium concentration of 311.13±3.7 mg/L NH₄⁺-N (C/N=30), where the cell density and PHB content were 3.86 g CDW per liter and 84.1%, respectively. Other inexpensive carbon sources were evaluated from the perspective of product yield (Y_P/S, gram PHB per gram substrate used), and the glycerol obtained the best results. Moreover, TAD1 could also utilize starch to produce PHB at elevated temperatures, which has rarely been reported by other microorganisms.