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Water Sci Technol

Title:		Production of polyhydroxyalkanoates by glycogen accumulating organisms treating a paper mill wastewater
Author(s):		Bengtsson S; Werker A; Welander T;
Address:		"AnoxKaldnes AB, Klosterangsvagen 11A, SE-226 47, Lund, Sweden. simon.bengtsson@anoxkaldnes.com"
Journal Title:		Water Sci Technol
Year:		2008
Volume:		58
Issue:		2
Page Number:		323 - 330
DOI:		10.2166/wst.2008.381
ISSN/ISBN:		0273-1223 (Print) 0273-1223 (Linking)
Abstract:		"A process for production of polyhydroxyalkanoates (PHA) by activated sludge treating a paper mill wastewater was investigated. The applied strategy was to select for glycogen accumulating organisms (GAOs) by alternating anaerobic/aerobic conditions. Acidogenic fermentation was used as pretreatment to convert various organic compounds to volatile fatty acids which are preferable substrates for PHA production. Enrichment resulted in a culture dominated by GAOs related to Defluviicoccus vanus (56%) and Candidatus Competibacter phosphatis (22%). Optimization of PHA accumulation by the enriched GAO culture was performed through batch experiments. Accumulation of PHA under anaerobic conditions was limited by the intracellular glycogen stored. Under aerobic conditions significant glycogen production (to 25% of sludge dry weight) was observed alongside PHA accumulation (to 22% of sludge dry weight). By applying a subsequent anaerobic period after an initial aerobic, the produced glycogen could be utilized for further PHA accumulation and by this strategy PHA content was increased to 42% of sludge dry weight. The PHA yield over the entire process was 0.10 kg per kg of influent COD treated which is similar to what has been achieved with a process applying feast/famine enrichment strategy with the same wastewater"
Keywords:		"Acetates/metabolism Anaerobiosis Bacteria/*metabolism Fermentation Glycogen/*metabolism *Industrial Waste Paper Polyhydroxyalkanoates/*biosynthesis/chemistry Propionates/metabolism Time Factors Waste Disposal, Fluid/*methods;"
Notes:		"MedlineBengtsson, Simon Werker, Alan Welander, Thomas eng England 2008/08/15 Water Sci Technol. 2008; 58(2):323-30. doi: 10.2166/wst.2008.381"