Bioconversion of Brown Algae Sargassum horneri into Ethanol by Simultaneous Saccharification and Fermentation by Mannitol-fermenting Saccharomyces cerevisiae

Abstract

Sargassum horneri is a sea-drifting brown macroalga often found along the coast of East Asian countries. It was recently found to be drifting from China toward Jeju Island in South Korea, causing damage to fisheries and vessels. Being considered as a marine waste, a huge amount of S. horneri was collected in the past 5 years, but an efficient and proper way to treat it has still not been found. Therefore, it is required to develop technologies to tackle this issue. Here, we conducted bioconversion of S. horneri by the yeast Saccharomyces cerevisiae in order to utilize it as a biomass source for producing ethanol. First, S. cerevisiae was engineered to extend its substrate range to mannitol, which is one of the major components of brown algae. Activation of the native HXT17 and MAN2 genes enabled the yeast to metabolize mannitol as the sole carbon source. Impact of pretreatment conditions, the type of hydrolytic enzymes, and biomass solid loadings on the ethanol production by the yeast were evaluated. The highest ethanol productivity was obtained when the biomass was pretreated at 121 o C and ethanol concentration was the highest when the biomass loading was 24% (w/v), giving the maximum concentrations of monosaccharides and ethanol of 47.29 g/ L and 22.94 g/L, respectively. The results obtained from this study suggest possible utilization of S. horneri as a raw material for cellulosic bioethanol production.

Thermodynamic Properties in the Process of Thawing for Cryopreservation of Algae

“…유용미생물의 활성화를 이용하여 비료, 가축 및 어 •패류의 사료 제조에 이용되고 있으며, 종이 코팅, 접착 제, 염료, 젤 등의 산업용 제품과 치약, 화장품, 구취제 등의 생활용품의 원료로 그 활용 범위가 다양하고, 생물환경의 보 존 및 회복을 위한 CO 2 제거 및 바이오메탄 생산 등의 소재 물질로서도 그 가치와 유용성이 증대되고 있다 [7][8][9][10][11][12][13][14]. 해조류를 이용한 바이오 에너지에 대한 연구로는 지구 온 난화와 기후 변화에 대응하는 해양 대형 조류인 Sargassum horneri 로부터 바이오 에너지의 생산 [15], 해조류 바이오매 스로부터 바이오 당 생산 [16], 해조류 우뭇가사리(Gelidium amansii)의 분리당화발효를 이용한 바이오 에탄올 생산에 관 한 연구 [17] 등이 있다. 해조류에 대한 품질성, 보존성, 유전적 안정성을 높이기 위 하여 장기간 안정적인 생산 및 종묘의 보존성이 높은 것으로 보고된 액체질소 동결보존법이 널리 이용되어 왔다 [18][19][20].…”