The effect of methane and odd-chain fatty acids on 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV) synthesis by a Methylosinus-dominated mixed culture

Bioresources and Bioprocessing

Paul Jensen¹  Peter James Strong²  Bronwyn Laycock³  Paul Andrew Lant³  Syarifah Nuraqmar Syed Mahamud³  Steven Pratt³  Pawarisa Luangthongkam⁴  Gene Tyson⁵  Paul Evans⁵ 

[1] Advanced Water Management Centre, The University of Queensland, 4072, Brisbane, QLD, Australia;Queensland University of Technology, 2 George Street, 4000, Brisbane, QLD, Australia;School of Chemical Engineering, The University of Queensland, 4072, St. Lucia, Brisbane, QLD, Australia;School of Chemical Engineering, The University of Queensland, 4072, St. Lucia, Brisbane, QLD, Australia;Queensland University of Technology, 2 George Street, 4000, Brisbane, QLD, Australia;The Australian Centre for Ecogenomics, The University of Queensland, 4072, Brisbane, QLD, Australia;

关键词: Methane;    Methanotrophs;    Polyhydroxyalkanoates;    3-Hydroxybutyrate;    3-Hydroxyvalerate;   

DOI  :  10.1186/s40643-019-0285-1

来源: Springer

【 摘 要 】

A methanotrophic community was enriched in a semi-continuous reactor under non-aseptic conditions with methane and ammonia as carbon and nitrogen source. After a year of operation, Methylosinus sp., accounted for 80% relative abundance of the total sequences identified from potential polyhydroxyalkanoates (PHAs) producers, dominated the methane-fed enrichment. Prior to induction of PHA accumulation, cells harvested from the parent reactor contained low level of PHA at 4.0 ± 0.3 wt%. The cells were later incubated in the absence of ammonia with various combinations of methane, propionic acid, and valeric acid to induce biosynthesis of poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). Previous studies reported that methanotrophic utilization of odd-chain fatty acids for the production of PHAs requires reducing power from methane oxidation. However, our findings demonstrated that the PHB-containing methanotrophic enrichment does not require methane availability to generate 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV)—when odd-chain fatty acids are presented. The enrichment yielded up to 14 wt% PHA with various mole fractions of 3HV monomer depending on the availability of methane and odd-fatty acids. Overall, the addition of valeric acid resulted in a higher PHA content and a higher 3HV fraction. The highest 3HV fraction (up to 65 mol%) was obtained from the methane–valeric acid experiment, which is higher than those previously reported for PHA-producing methanotrophic mixed microbial cultures.

【 授权许可】

CC BY