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.

Subject Categories:

  • Microbiology
  • Plastics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE