Production of hexanoic acid from D-galactitol by a newly isolated Clostridium sp. BS-1.
In a study screening anaerobic microbes utilizing D: -galactitol as a fermentable carbon source, four bacterial strains were isolated from an enrichment culture producing H₂, ethanol, butanol, acetic acid, butyric acid, and hexanoic acid. Among these isolates, strain BS-1 produced hexanoic acid as a major metabolic product of anaerobic fermentation with D: -galactitol. Strain BS-1 belonged to the genus Clostridium based on phylogenetic analysis using 16S rRNA gene sequences, and the most closely related strain was Clostridium sporosphaeroides DSM 1294(T), with 94.4% 16S rRNA gene similarity. In batch cultures, Clostridium sp. BS-1 produced 550 ± 31 mL L⁻¹ of H₂, 0.36 ± 0.01 g L⁻¹ of acetic acid, 0.44 ± 0.01 g L⁻¹ of butyric acid, and 0.98 ± 0.03 g L⁻¹ of hexanoic acid in a 4-day cultivation. The production of hexanoic acid increased to 1.22 and 1.73 g L⁻¹ with the addition of 1.5 g L⁻¹ of sodium acetate and 100 mM 2-(N-morpholino)ethanesulfonic acid (MES), respectively. Especially when 1.5 g L⁻¹ of sodium acetate and 100 mM MES were added simultaneously, the production of hexanoic acid increased up to 2.99 g L⁻¹. Without adding sodium acetate, 2.75 g L⁻¹ of hexanoic acid production from D-galactitol was achieved using a coculture of Clostridium sp. BS-1 and one of the isolates, Clostridium sp. BS-7, in the presence of 100 mM MES. In addition, volatile fatty acid (VFA) production by Clostridium sp. BS-1 from D-galactitol and D: -glucose was enhanced when a more reduced culture redox potential (CRP) was applied via addition of Na₂S·9H₂O.
Jeon
Byoung Seung
BS
Clean Energy Center, Korea Institute of Science and Technology, Seongbuk-gu, Seoul, Republic of Korea.
Kim
Byung-Chun
BC
Um
Youngsoon
Y
Sang
Byoung-In
BI
D019342:Acetic Acid / Q000378:metabolism; D000693:Anaerobiosis; D001483:Base Sequence; D056804:Biofuels; D020148:Butyric Acid / Q000378:metabolism; D002208:Caproates / Q000302:isolation & purification / Q000378:metabolism*; D003013:Clostridium / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D005285:Fermentation / Q000235:genetics; D004376:Galactitol / Q000378:metabolism*; D020459:Genes, rRNA; D010084:Oxidation-Reduction; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D012722:Sewage; D019346:Sodium Acetate / Q000378:metabolism; D014871:Water Microbiology
D056804:Biofuels; D002208:Caproates; D012336:RNA, Ribosomal, 16S; D012722:Sewage; D020148:Butyric Acid; D004376:Galactitol; C037652:hexanoic acid; D019346:Sodium Acetate; D019342:Acetic Acid