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Production of polyhydroxyalkanoates from fermented sugar cane molasses by a mixed culture enriched in glycogen accumulating organisms

Paper ID Volume ID Publish Year Pages File Format Full-Text
24480 43518 2010 11 PDF Available
Title
Production of polyhydroxyalkanoates from fermented sugar cane molasses by a mixed culture enriched in glycogen accumulating organisms
Abstract

Batch production of polyhydroxyalkanoates (PHAs) under aerobic conditions by an open mixed culture enriched in glycogen accumulating organisms (GAOs) with fermented sugar cane molasses as substrate was studied. The produced polymers contained five types of monomers, namely 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV), 3-hydroxy-2-methylbutyrate (3H2MB), 3-hydroxy-2-methylvalerate (3H2MV) and the medium chain length monomer 3-hydroxyhexanoate (3HHx). With fermented molasses as substrate, PHA was produced under concurrent consumption of stored glycogen with yields of 0.47–0.66 C-mol PHA per C-mol of total carbon substrate and with rates up to 0.65 C-mol/C-mol X h. In order to investigate the role of glycogen during aerobic PHA accumulation in GAOs, synthetic single volatile fatty acids (VFAs) were used as substrates and it was found that the fate of glycogen was dependent on the type of VFA being consumed. Aerobic PHA accumulation occurred under concurrent glycogen consumption with acetate as substrate and under minor concurrent glycogen production with propionate as substrate. With butyrate and valerate as substrates, PHA accumulation occurred with the glycogen pool unaffected. The composition of the PHA was dependent on the VFA composition of the fermented molasses and was 56–70 mol-% 3HB, 13–43 mol-% 3HV, 1–23 mol-% 3HHx and 0–2 mol-% 3H2MB and 3H2MV. The high polymer yields and production rates suggest that enrichment of GAOs can be a fruitful strategy for mixed culture production of PHA from waste substrates.

Keywords
Polyhydroxyalkanoates; Mixed culture; Glycogen accumulating organisms (GAOs); 3-Hydroxyhexanoate; Sugar cane molasses
First Page Preview
Production of polyhydroxyalkanoates from fermented sugar cane molasses by a mixed culture enriched in glycogen accumulating organisms
Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Biotechnology - Volume 145, Issue 3, 1 February 2010, Pages 253–263
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering