title: Butyric acid production from red algae by a newly isolated Clostridium sp. S1.
abstract: OBJECTIVE
  To produce butyric acid from red algae such as Gelidium amansii in which galactose is a main carbohydrate, microorganisms utilizing galactose and tolerating inhibitors in hydrolysis including levulinic acid and 5-hydroxymethylfurfural (HMF) are required.
  
  
  RESULTS
  A newly isolated bacterium, Clostridium sp. S1 produced butyric acid not only from galactose as the sole carbon source but also from a mixture of galactose and glucose through simultaneous utilization. Notably, Clostridium sp. S1 produced butyric acid and a small amount of acetic acid with the butyrate:acetate ratio of 45.4:1 and it even converted acetate to butyric acid. Clostridium sp. S1 tolerated 0.5-2 g levulinic acid/l and recovered from HMF inhibition at 0.6-2.5 g/l, resulting in 85-92% butyric acid concentration of the control culture. When acid-pretreated G. amansii hydrolysate was used, Clostridium sp. S1 produced 4.83 g butyric acid/l from 10 g galactose/l and 1 g glucose/l.
  
  
  CONCLUSIONS
  Clostridium sp. S1 produces butyric acid from red algae due to its characteristics in sugar utilization and tolerance to inhibitors, demonstrating its advantage as a red algae-utilizing microorganism.
authors.affiliation: Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea.
authors.forename: Kyung Min
authors.initials: KM
authors.lastname: Lee
authors.forename: Okkyoung
authors.initials: O
authors.lastname: Choi
authors.forename: Ki-Yeon
authors.initials: KY
authors.lastname: Kim
authors.forename: Han Min
authors.initials: HM
authors.lastname: Woo
authors.forename: Yunje
authors.initials: Y
authors.lastname: Kim
authors.forename: Sung Ok
authors.initials: SO
authors.lastname: Han
authors.forename: Byoung-In
authors.initials: BI
authors.lastname: Sang
authors.forename: Youngsoon
authors.initials: Y
authors.lastname: Um
mesh_terms: D020148:Butyric Acid / Q000378:metabolism*; D003013:Clostridium / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D005690:Galactose / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D007982:Levulinic Acids / Q000494:pharmacology; D010802:Phylogeny; D010936:Plant Extracts / Q000737:chemistry; D000461:Rhodophyta / Q000737:chemistry*
chemical_list: D007982:Levulinic Acids; D010936:Plant Extracts; D020148:Butyric Acid; D005947:Glucose; C032246:levulinic acid; D005690:Galactose