Selection of Type I and Type II methanotrophic proteobacteria in a fluidized bed reactor under non-sterile conditions.
Bioresour Technol
; 102(21): 9919-26, 2011 Nov.
Article
in En
| MEDLINE
| ID: mdl-21906939
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 mg/L), 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 N(2) as the N-source, and maintaining a low influent DO (2.0mg/L). The resulting biofilms contained both Types I and II methanotrophs. Batch tests indicated that biofilm samples grown with N(2) 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 N(2) as N-source and low DO.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Bioreactors
/
Methylosinus
/
Methylocystaceae
Language:
En
Journal:
Bioresour Technol
Journal subject:
ENGENHARIA BIOMEDICA
Year:
2011
Document type:
Article
Affiliation country:
Estados Unidos