Functional Stability of a Mixed Microbial
Consortium Producing PHA From Waste
Department of Civil Engineering, University of Idaho, PO Box 441022,
Moscow, Idaho 83844-1022;
Department of Civil and Environmental
Engineering, University of California Davis, 1 Shields Avenue, Davis,
CA 95616, E-mail: email@example.com;
Biotechnology Department, Idaho
National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-2203;
Department of Civil and Environmental Engineering, Washington State
University, Pullman, WA 99164-2910
Polyhydroxyalkanoates (PHAs) represent an environmentally effective
alternative to synthetic thermoplastics; however, current production practices
are not sustainable. In this study, PHA production was accomplished in
sequencing batch bioreactors utilizing real wastewaters and mixed microbial
consortia from municipal activated sludge as inoculum. Polymer production
reached 85, 53, and 10% of the cell dry weight from methanol-enriched pulp
and paper mill foul condensate, fermented municipal primary solids, and
biodiesel wastewater, respectively. Using denaturing gradient gel elec-
trophoresis of 16S-rDNA from polymerase chain reaction-amplified DNA
extracts, distinctly different communities were observed between and within
wastewaters following enrichment. Most importantly, functional stability was
maintained despite differing and contrasting microbial populations.
Index Entries: Activated sludge; denaturing gradient gel electrophoresis;
polyhydroxyalkanoates; wastewater; primary solids fermentate; foul con-
densate; environmental biotechnology.
Engineered biological systems have historically been utilized prin-
cipally for the remediation and/or treatment of anthropogenic-derived
pollution. Only in recent years has this environmental management dis-
cipline, appropriately referred to as environmental biotechnology (1),
been recognized for its potential to synthesize commodities and provide
services beyond waste treatment (1). However, this proposition is not
Applied Biochemistry and Biotechnology
Vol. 136–140, 2007
Copyright © 2007 by Humana Press Inc.
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