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Accession Number:
ADA551822
Title:
Selection of Type I and Type II Methanotrophic Proteobacteria in a Fluidized Bed Reactor under Non-Sterile Conditions
Descriptive Note:
Journal article
Corporate Author:
MILITARY ACADEMY WEST POINT NY
Report Date:
2011-08-01
Pagination or Media Count:
10.0
Abstract:
Type II methanotrophs produce polyhydroxybutyrate PHB, while Type I methanotrophs do not. A laboratory-scale fluidized bed reactor was initially inoculated with a Type II Methylocystis-like dominated culture. At elevated levels of dissolved oxygen DO, 9 mgL, pH of 6.2-6.5 with nitrate as the N-source a Methylobacter-like Type I methanotroph became dominant within the biofilms which did not produce PHB. A shift to biofilms capable of PHB production was achieved by re-inoculating with Type II Methylosinus culture, providing dissolved N2 as the N-source, and maintaining a low influent DO 2.0 mgL. The resulting biofilms contained both Types I and II methanotrophs. Batch tests indicated that biofilm samples grown with N2 became dominated by Type II methanotrophs and produced PHB. Enrichments with nitrate or ammonium were dominated by Type I methanotrophs without PHB production capability. The key selection factors favoring Type II were N2 as N-source and low DO.
Distribution Statement:
APPROVED FOR PUBLIC RELEASE