title: Bioprocess development on microalgae-based CO2 fixation and bioethanol production using Scenedesmus obliquus CNW-N.
abstract: A two-stage cultivation strategy was applied to achieve greater CO2 fixation and carbohydrate productivity with an indigenous microalga Scenedesmus obliquus CNW-N, which was first cultivated using a nutrient-rich medium to promote cell growth, and was then switched to a nutrient-deficient condition to trigger carbohydrate accumulation. The optimal biomass productivity, carbohydrate productivity, and CO2 fixation rate were 681.4, 352.9, and 1192.5 mg L(-1) d(-1), respectively, with a 51.8% carbohydrate content (based on dry weight). This performance is better than the results in most related studies. The microalgal carbohydrate was mainly composed of glucose, which accounts for nearly 80% of total sugars. Dilute acid hydrolysis with 2% H2SO4 can saccharify the wet microalgal biomass effectively, achieving a glucose yield of 96-98%. Using the acidic hydrolysate of the microalga as feedstock, the separate hydrolysis and fermentation (SHF) process gave an ethanol concentration of 8.55 g L(-1), representing a theoretical yield of nearly 99.8%.
authors.affiliation: Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Shih-Hsin
authors.initials: SH
authors.lastname: Ho
authors.forename: Po-Jen
authors.initials: PJ
authors.lastname: Li
authors.forename: Chen-Chun
authors.initials: CC
authors.lastname: Liu
authors.forename: Jo-Shu
authors.initials: JS
authors.lastname: Chang
mesh_terms: D056804:Biofuels; D018533:Biomass; D019149:Bioreactors; D057486:Carbon Cycle / Q000502:physiology; D002245:Carbon Dioxide / Q000378:metabolism*; D000431:Ethanol / Q000378:metabolism*; D006868:Hydrolysis; D044444:Scenedesmus / Q000378:metabolism*; D013696:Temperature
chemical_list: D056804:Biofuels; D002245:Carbon Dioxide; D000431:Ethanol
keywords: Acid hydrolysis; Bioethanol; Carbohydrate; Microalgae; Scenedesmus obliquus