title: Precultivation of Bacillus coagulans DSM2314 in the presence of furfural decreases inhibitory effects of lignocellulosic by-products during L(+)-lactic acid fermentation.
abstract: By-products resulting from thermo-chemical pretreatment of lignocellulose can inhibit fermentation of lignocellulosic sugars to lactic acid. Furfural is such a by-product, which is formed during acid pretreatment of lignocellulose. pH-controlled fermentations with 1 L starting volume, containing YP medium and a mixture of lignocellulosic by-products, were inoculated with precultures of Bacillus coagulans DSM2314 to which 1 g/L furfural was added. The addition of furfural to precultures resulted in an increase in L(+)-lactic acid productivity by a factor 2 to 1.39 g/L/h, an increase in lactic acid production from 54 to 71 g and an increase in conversion yields of sugar to lactic acid from 68 to 88 % W/W in subsequent fermentations. The improved performance was not caused by furfural consumption or conversion, indicating that the cells acquired a higher tolerance towards this by-product. The improvement coincided with a significant elongation of B. coagulans cells. Via RNA-Seq analysis, an upregulation of pathways involved in the synthesis of cell wall components such as bacillosamine, peptidoglycan and spermidine was observed in elongated cells. Furthermore, the gene SigB and genes promoted by SigB, such as NhaX and YsnF, were upregulated in the presence of furfural. These genes are involved in stress responses in bacilli.
authors.affiliation: Food and Biobased Research, Wageningen University and Research Centre, PO Box 17, 6700 AA, Wageningen, The Netherlands.|Bioprocess Engineering, Wageningen University and Research Centre, PO Box 16, 6700 AA, Wageningen, The Netherlands.
authors.forename: Edwin
authors.initials: E
authors.lastname: van der Pol
authors.affiliation: Food and Biobased Research, Wageningen University and Research Centre, PO Box 17, 6700 AA, Wageningen, The Netherlands.
authors.forename: Jan
authors.initials: J
authors.lastname: Springer
authors.affiliation: Corbion Purac Biochem, PO Box 21, 4200 AA, Gorinchem, The Netherlands.
authors.forename: Bastienne
authors.initials: B
authors.lastname: Vriesendorp
authors.affiliation: Bioprocess Engineering, Wageningen University and Research Centre, PO Box 16, 6700 AA, Wageningen, The Netherlands.
authors.forename: Ruud
authors.initials: R
authors.lastname: Weusthuis
authors.affiliation: Food and Biobased Research, Wageningen University and Research Centre, PO Box 17, 6700 AA, Wageningen, The Netherlands. gerrit.eggink@wur.nl.|Bioprocess Engineering, Wageningen University and Research Centre, PO Box 16, 6700 AA, Wageningen, The Netherlands. gerrit.eggink@wur.nl.
authors.forename: Gerrit
authors.identifier: http://orcid.org/0000-0002-9867-6468
authors.initials: G
authors.lastname: Eggink
mesh_terms: D000222:Adaptation, Physiological; D000070000:Bacillus coagulans / Q000187:drug effects* / Q000378:metabolism* / Q000502:physiology; D053898:Biosynthetic Pathways / Q000235:genetics; D002473:Cell Wall / Q000378:metabolism; D003470:Culture Media / Q000737:chemistry; D004361:Drug Tolerance; D005285:Fermentation; D005662:Furaldehyde / Q000378:metabolism* / Q000633:toxicity; D020869:Gene Expression Profiling; D019344:Lactic Acid / Q000378:metabolism*; D008031:Lignin / Q000378:metabolism*
chemical_list: D003470:Culture Media; C036909:lignocellulose; D019344:Lactic Acid; D008031:Lignin; D005662:Furaldehyde
keywords: Adaptation; B. coagulans; Lactic acid fermentation; Lignocellulosic by-products