Bioethanol production using carbohydrate-rich microalgae biomass as feedstock

• Published in: Bioresource technology Vol. 135; pp. 191 - 198
• Main Authors: Ho, Shih-Hsin, Huang, Shu-Wen, Chen, Chun-Yen, Hasunuma, Tomohisa, Kondo, Akihiko, Chang, Jo-Shu
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.05.2013
• Subjects: Acid hydrolysis; analysis; Biofuels; Biofuels - microbiology; Biomass; biosynthesis; Biotechnology; Biotechnology - methods; Carbohydrate; Carbohydrate Metabolism; Carbohydrate Metabolism - drug effects; Carbohydrates; Carbohydrates - biosynthesis; Chlorella vulgaris; Chlorella vulgaris - drug effects; Chlorella vulgaris - growth & development; Chlorella vulgaris - metabolism; drug effects; Enzymatic hydrolysis; Ethanol; Ethanol - metabolism; ethanol production; Ethyl alcohol; Feedstock; feedstocks; fermentation; Fermentation - drug effects; Glucose; Glucose - biosynthesis; Glucosidases; Glucosidases - metabolism; growth & development; Hydrolysates; Hydrolysis; Hydrolysis - drug effects; Lipids; Lipids - analysis; metabolism; methods; Microalgae; Microalgae - drug effects; Microalgae - growth & development; Microalgae - metabolism; microbiology; Nitrates; Nitrates - analysis; Nitrogen; Nitrogen - pharmacology; pharmacology; Proteins; Proteins - analysis; sulfuric acid; Sulfuric Acids; Sulfuric Acids - pharmacology; Time Factors; Zymomonas; Zymomonas - drug effects; Zymomonas - metabolism; Acid hydrolysis; Microalgae; Carbohydrate; Chlorella vulgaris; Enzymatic hydrolysis
• ISSN: 0960-8524; 1873-2976; 1873-2976
• DOI: 10.1016/j.biortech.2012.10.015

► A sugar-rich Chlorella vulgaris FSP-E strain was used as feedstock for ethanol production. ► Enzymatic and acidic hydrolyses can efficiently saccharify the microalgae biomass. ► SHF & SSF processes produced ethanol from the microalgae biomass with high yield. ► SSF process gave better ethanol production performance with a 92% theoretical yield. This study aimed to evaluate the potential of using a carbohydrate-rich microalga Chlorella vulgaris FSP-E as feedstock for bioethanol production via various hydrolysis strategies and fermentation processes. Enzymatic hydrolysis of C. vulgaris FSP-E biomass (containing 51% carbohydrate per dry weight) gave a glucose yield of 90.4% (or 0.461g (gbiomass)−1). The SHF and SSF processes converted the enzymatic microalgae hydrolysate into ethanol with a 79.9% and 92.3% theoretical yield, respectively. Dilute acidic hydrolysis with 1% sulfuric acid was also very effective in saccharifying C. vulgaris FSP-E biomass, achieving a glucose yield of nearly 93.6% from the microalgal carbohydrates at a starting biomass concentration of 50gL−1. Using the acidic hydrolysate of C. vulgaris FSP-E biomass as feedstock, the SHF process produced ethanol at a concentration of 11.7gL−1 and an 87.6% theoretical yield. These findings indicate the feasibility of using carbohydrate-producing microalgae as feedstock for fermentative bioethanol production.