title: Bioethanol production from Gracilaria verrucosa using Saccharomyces cerevisiae adapted to NaCl or galactose.
abstract: This study examined the pretreatment, enzymatic saccharification, and fermentation of the red macroalgae Gracilaria verrucosa using adapted saccharomyces cerevisiae to galactose or NaCl for the increase of bioethanol yield. Pretreatment with thermal acid hydrolysis to obtain galactose was carried out with 11.7% (w/v) seaweed slurry and 373 mM H2SO4at 121 °C for 59 min. Glucose was obtained from enzymatic hydrolysis. Enzymatic saccharification was performed with a mixture of 16 U/mL Celluclast 1.5L and Viscozyme L at 45 °C for 48 h. Ethanol fermentation in 11.7% (w/v) seaweed hydrolysate was carried out using Saccharomyces cerevisiae KCTC 1126 adapted or non-adapted to high concentrations of galactose or NaCl. When non-adapted S. cerevisiae KCTC 1126 was used, the ethanol productivity was 0.09 g/(Lh) with an ethanol yield of 0.25. Ethanol productivity of 0.16 and 0.19 g/(Lh) with ethanol yields of 0.43 and 0.48 was obtained using S. cerevisiae KCTC 1126 adapted to high concentrations of galactose and NaCl, respectively. Adaptation of S. cerevisiae KCTC 1126 to galactose or NaCl increased the ethanol yield via adaptive evolution of the yeast.
authors.affiliation: Department of Biotechnology, Pukyong National University, Busan, 48513, Korea.
authors.forename: Trung Hau
authors.initials: TH
authors.lastname: Nguyen
authors.affiliation: Department of Biotechnology, Pukyong National University, Busan, 48513, Korea.
authors.forename: Chae Hun
authors.initials: CH
authors.lastname: Ra
authors.affiliation: Department of Biotechnology, Pukyong National University, Busan, 48513, Korea.
authors.forename: InYung
authors.initials: I
authors.lastname: Sunwoo
authors.affiliation: Department of Biotechnology, Pukyong National University, Busan, 48513, Korea.
authors.forename: Gwi-Taek
authors.initials: GT
authors.lastname: Jeong
authors.affiliation: Department of Biotechnology, Pukyong National University, Busan, 48513, Korea. skkim@pknu.ac.kr.
authors.forename: Sung-Koo
authors.initials: SK
authors.lastname: Kim
mesh_terms: D000431:Ethanol / Q000378:metabolism*; D005690:Galactose / Q000494:pharmacology*; D044724:Gracilaria / Q000737:chemistry*; D012441:Saccharomyces cerevisiae / Q000254:growth & development*; D012965:Sodium Chloride / Q000494:pharmacology*
chemical_list: D000431:Ethanol; D012965:Sodium Chloride; D005690:Galactose
keywords: Adaptation; Enzymatic saccharification; Fermentation; Gracilaria verrucosa; Thermal acid hydrolysis