Batch cultivation of Methylosinus trichosporium OB3b. 5: Characterization of poly-{beta}-hydroxybutyrate production under methane-dependent growth conditions
- Lawrence Livermore National Lab., CA (United States)
Methanotrophs have promising applications in the bioremediation of chlorinated hydrocarbons and in the production of a biopolymer, poly-{beta}-hydroxybutyrate (PHB). Batch bioreactor culture conditions were studied for the accumulation of PHB by methane-grown Methylosinus trichosporium OB3b, and to evaluate the effect of PHB on the bacterial capacity to degrade trichloroethylene (TCE), a common groundwater contaminant. The PHB content of the washed and lyophilized cells was measured by gas chromatography (GC), after hydrochloric acid (HCl) propanolysis. A differential GC-based assay was developed for the monomer and the polymer of {beta}-hydroxybutyrate utilizing 1% and 10% HCl (v/v) reaction mixtures, respectively. During bioreactor growth in a Cu-deficient modified Higgins` medium, the cells accumulated PHB upon depletion of nitrate. A biomass yield of 3.2 g dry wt/L and a PHB accumulation of {approximately}10% (w/w) were reached after 140 to 160 h, without adversely affecting the propene or TCE epoxidation specific rate given by whole cells containing soluble methane monooxygenase (sMMO). The TCE biotransformation capacity ({approximately}0.25 mg TCE oxidized/mg dry cell wt) of resting cells containing {approximately}10% PHB was consistently {approximately}1.6-fold greater than that of cells containing only {approximately}2% PHB. Higher levels (>10%) of accumulated PHB did not enhance this biotransformation capacity further.
- OSTI ID:
- 182892
- Journal Information:
- Biotechnology and Bioengineering, Vol. 49, Issue 2; Other Information: PBD: 20 Jan 1996
- Country of Publication:
- United States
- Language:
- English
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