Elsevier

Bioresource Technology

Volume 228, March 2017, Pages 250-256
Bioresource Technology

A flexible microbial co-culture platform for simultaneous utilization of methane and carbon dioxide from gas feedstocks

https://doi.org/10.1016/j.biortech.2016.12.111Get rights and content
Under a Creative Commons license
open access

Highlights

  • A co-cultivation technology that converts, CH4 and CO2, into microbial biomass.

  • Robust bacterial growth on biogas and natural gas feedstocks.

  • Continuous co-cultivation without air or O2 feed to support CH4 oxidation.

  • A flexible co-culture technology constructed from genetically tractable bacteria.

Abstract

A new co-cultivation technology is presented that converts greenhouse gasses, CH4 and CO2, into microbial biomass. The methanotrophic bacterium, Methylomicrobium alcaliphilum 20z, was coupled to a cyanobacterium, Synechococcus PCC 7002 via oxygenic photosynthesis. The system exhibited robust growth on diverse gas mixtures ranging from biogas to those representative of a natural gas feedstock. A continuous processes was developed on a synthetic natural gas feed that achieved steady-state by imposing coupled light and O2 limitations on the cyanobacterium and methanotroph, respectively. Continuous co-cultivation resulted in an O2 depleted reactor and does not require CH4/O2 mixtures to be fed into the system, thereby enhancing process safety considerations over traditional methanotroph mono-culture platforms. This co-culture technology is scalable with respect to its ability to utilize different gas streams and its biological components constructed from model bacteria that can be metabolically customized to produce a range of biofuels and bioproducts.

Keywords

Methane
Carbon dioxide
Co-culture
Biogas
Natural gas
Methanotroph
Cyanobacteria

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