Open AccessBiopolymers made from methane in bioreactors
Author(s) -
Chidambarampadmavathy Karthigeyan,
Karthikeyan Obulisamy P.,
Heimann Kirsten
Publication year - 2015
Publication title -
engineering in life sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.547
H-Index - 57
eISSN - 1618-2863
pISSN - 1618-0240
DOI - 10.1002/elsc.201400203
Subject(s) - continuous stirred tank reactor , bioreactor , biomass (ecology) , chemistry , compost , aeration , methane , polyhydroxybutyrate , pulp and paper industry , methanogenesis , environmental engineering , waste management , environmental science , organic chemistry , agronomy , biology , engineering , genetics , bacteria
Methane (CH 4 ) is a potent greenhouse gas and mitigation is important to reduce global warming impacts. In this study, we aimed to convert CH 4 to polyhydroxybutyrate (PHB; a biopolymer) by enrichment of methanotrophic consortia in bioreactors. Two different methanotrophic consortia were established form landfill top‐cover (landfill biomass [LB]) and compost soils (compost biomass [CB]), through cultivation under CH 4 :CO 2 :air (30:10:60) in batch systems. The established cultures were then used as inoculi (0.5 g LB or CB⋅L −1 ) in continuous stirred tank reactors (CSTRs) aerated with CH 4 :CO 2 :air at 0.25 L⋅min −1 . Under stable CSTRs operating conditions, the effect of spiking with 1:1 copper:iron (final concentrations of 5μM) was tested. Methane oxidation capacity (MOC), biomass dry weight (DW biomass ), PHB, and fatty acid methyl esters (FAMEs) contents were used as effect parameters. A maximum MOC of 481.9 ± 8.9 and 279.6 ± 11.3 mg CH 4 ⋅g −1 DW biomass ⋅h −1 was recorded in LB‐CSTR and CB‐CSTR, respectively, but PHB production was similar for both systems, that is 37.7 mg⋅g −1 DW biomass . Treatment with copper and iron improved PHB production (22.5% of DW biomass ) in LB‐CSTR, but a reduction of 13.6% was observed in CB‐CSTR. The results indicated that CH 4 to PHB conversion is feasible using LB‐CSTRs and addition of copper and iron is beneficial.