Conversion of Xylose from Birch Hemicellulose Hydrolysate to 2,3-Butanediol with Bacillus vallismortis

Anja Kuenz,Mari Kallioinen,Harri Niemi,Mika Mänttäri,Malee Jäger,Ulf Prüße

doi:10.3390/fermentation6030086

Anja Kuenz, Mari Kallioinen + Show 4 more

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https://doi.org/10.3390/fermentation6030086

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Abstract

Biotechnologically produced 2,3-butanediol (2,3-BDO) is a potential starting material for industrial bulk chemicals, such as butadiene or methyl ethyl ketone, which are currently produced from fossil feedstocks. So far, the highest 2,3-BDO concentrations have been obtained with risk class 2 microorganisms and pure glucose as substrate. However, as glucose stays in competition to food and feed industries, a lot of effort has been done in the last years finding efficient alternative substrates. Thereby xylose from hydrolysed wood hemicelluloses is a promising substrate for the production of 2,3-BDO. The risk class 1 microorganism Bacillus vallismortis strain was identified as a very promising 2,3-BDO producer. The strain is able to utilize xylose almost in the same manner as glucose. B. vallismortis is less prone to common inhibiting compounds in lignocellulosic extracts/hydrolysates. When using a concentrated hemicellulose fraction from birch wood hydrolysate, which was produced with ultrafiltration and after which the acetate concentration was reduced, a yield of 0.43 g g−1 was achieved and the xylose consumption and the 2,3-BDO production is basically the same as using pure xylose.

Highlights

Due to the finiteness of fossil resources, the increasing demand for energy and raw materials [1], due to the growing world population and rising living standards [2], as well as the progressing climate change, other ways must be found to produce daily products
The 2,3-BDO as a chiral bivalent alcohol has two chiral centres that results in three possible stereoisomeric forms: two optically active isomers D-(−)- and L-(+)-2,3-BDO as well as the optical inactive meso-2,3-BDO isomer
2,3-BDO is a product of the mixed acid fermentation and the carbon source is metabolized in the case of hexoses and pentoses via the glycolysis or the pentose phosphate pathway to

Summary

Introduction

Due to the finiteness of fossil resources, the increasing demand for energy and raw materials [1], due to the growing world population and rising living standards [2], as well as the progressing climate change, other ways must be found to produce daily products. Numerous daily products like plastics, paints, detergents, and cleaning products are produced from fossil feedstocks. Renewable raw materials and residues from the agricultural and forestry sector represent potential, alternative raw material sources. By means of chemical or biotechnical conversion processes, the alternative raw materials can be converted into industrially usable chemicals. Produced 2,3-butanediol is a potential starting material for industrial bulk chemicals, such as butadiene or methyl ethyl ketone, which are produced to date from fossil feedstocks

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