title: Microalgal lipid production using the hydrolysates of rice straw pretreated with gamma irradiation and alkali solution.
abstract: BACKGROUND
  Lignocellulosic biomass has long been recognized as a potential sustainable source of sugars for biofuels. However, many physicochemical structural and compositional factors inhibit the enzymatic digestibility of the lignocellulosic biomass. In this study, efficient pretreatment method of rice straw (RS) was developed and the RS hydrolysate was applied in the cultivation of microalgae for lipid production.
  
  
  RESULTS
  Gamma ray irradiation (GRI) and alkali solution were used for the pretreatment, and saccharification was carried out with lignocellulolytic enzymes. When RS was pretreated by combined GRI and alkali method, the glucose and xylose saccharification yield after enzymatic hydrolysis increased up to 91.65 and 98.84 %, respectively. The enzymatic hydrolysate from the RS pretreated with the combined method was used to cultivate Chlorella protothecoides for lipid production. The maximum concentrations of biomass and fatty acid methyl ester of cells were 6.51 and 2.95 g/L, respectively. The lipid content of C. protothecoides from RS hydrolysate was comparable to that from glucose, and the lipid composition was similar between different carbon sources.
  
  
  CONCLUSIONS
  These results demonstrate that the combined pretreatment with gamma irradiation was highly effective in preparing hydrolysate, and the rice straw hydrolysate could be used as an alternative carbon source for microalgal lipid production for biofuel.
authors: Department of Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, 580-185 Republic of Korea ; School of Biological Sciences and Biotechnology, Chonnam National University, Gwangju, 500-757 Republic of Korea.
authors: Min-Ho
authors: MH
authors: Joe
authors: Department of Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, 580-185 Republic of Korea.
authors: Ji-Youn
authors: JY
authors: Kim
authors: Department of Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, 580-185 Republic of Korea.
authors: Sangyong
authors: S
authors: Lim
authors: Department of Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, 580-185 Republic of Korea.
authors: Dong-Ho
authors: DH
authors: Kim
authors: Department of Biological Sciences, College of Natural Sciences, Chonnam National University, Gwangju, 500-757, Republic of Korea.
authors: Suk
authors: S
authors: Bai
authors: Korea Polar Research Institute, Incheon, 406-840 Republic of Korea.
authors: Hyun
authors: H
authors: Park
authors: Korea Polar Research Institute, Incheon, 406-840 Republic of Korea.
authors: Sung Gu
authors: SG
authors: Lee
authors: Korea Polar Research Institute, Incheon, 406-840 Republic of Korea.
authors: Se Jong
authors: SJ
authors: Han
authors: Department of Biotechnology and Bioengineering, Chonnam National University, Gwangju, 500-757 Republic of Korea.
authors: Jong-Il
authors: JI
authors: Choi
keywords: Gamma ray irradiation; Lipid; Microalgae; Pretreatment; Rice straw