Conversion of solvent evaporation residues from the AB- (acetone - butanol) bioprocess into bacterial cells accumulating thermoplastic polyesters.
In a bioconversion study based on utilisation of by-products from the AB- (acetone - butanol) bioprocess a new isolated gram-negative solvent tolerant bacterium was used to convert the AB process residue after removal of the major part of the solvents. The bacterium identified as a representative of the genus Alcaligenes (designated as Alcaligenes sp. G) was capable of growth up to optical densities ranging from 8 to 20 and simultaneously of polyhydroxyalkanoate-(PHA-)accumulation up to 40% per dry weight. A standardised medium based on AB by-products containing 7 g/l of butyrate and 5 g/l of acetate at pH 7.5 was used in our studies for bioconversion into PHAs. Concentrations of 1-butanol, which is known for its membrane damaging properties in microorganisms, were tolerated in the AB by-products medium up to 4 g/l without significant inhibition of cellular growth. No inhibition of growth was observed, when the medium was adjusted to 40 g/l butyrate. Due to the toxicity of the remaining 1-butanol maintenance of sterility is of no high priority during the process. The use of acetate and butyrate from an AB process is expected to provide a higher return-on-investment than the combustion of biogas to help meet energy demands.
Institute for Microbiology and Genetics, University of Vienna, Austria.
G
G
Parrer
G
G
Schroll
J R
JR
Gapes
W
W
Lubitz
K C
KC
Schuster
D000096:Acetone / Q000378:metabolism*; D000332:Aerobiosis; D000421:Alcaligenes / Q000378:metabolism* / Q000502:physiology; D019149:Bioreactors; D001709:Biotechnology / Q000379:methods*; D000440:Butanols / Q000378:metabolism*; D002087:Butyrates / Q000378:metabolism; D002455:Cell Division; D006880:Hydroxy Acids / Q000378:metabolism*; D013379:Substrate Specificity
D000440:Butanols; D002087:Butyrates; D006880:Hydroxy Acids; D000096:Acetone