Fermentation of lignocellulosic sugars to acetic acid by Moorella thermoacetica
- 525 Downloads
A systematic study of bioconversion of lignocellulosic sugars to acetic acid by Moorella thermoacetica (strain ATCC 39073) was conducted. Four different water-soluble fractions (hydrolysates) obtained after steam pretreatment of lignocellulosic biomass were selected and fermented to acetic acid in batch fermentations. M. thermoacetica can effectively ferment xylose and glucose in hydrolysates from wheat straw, forest residues, switchgrass, and sugarcane straw to acetic acid. Xylose and glucose were completely utilized, with xylose being consumed first. M. thermoacetica consumed up to 62 % of arabinose, 49 % galactose and 66 % of mannose within 72 h of fermentation in the mixture of lignocellulosic sugars. The highest acetic acid yield was obtained from sugarcane straw hydrolysate, with 71 % of theoretical yield based on total sugars (17 g/L acetic acid from 24 g/L total sugars). The lowest acetic acid yield was observed in forest residues hydrolysate, with 39 % of theoretical yield based on total sugars (18 g/L acetic acid from 49 g/L total sugars). Process derived compounds from steam explosion pretreatment, including 5-hydroxymethylfurfural (0.4 g/L), furfural (0.1 g/L) and total phenolics (3 g/L), did not inhibit microbial growth and acetic acid production yield. This research identified two major factors that adversely affected acetic acid yield in all hydrolysates, especially in forest residues: (i) glucose to xylose ratio and (ii) incomplete consumption of arabinose, galactose and mannose. For efficient bioconversion of lignocellulosic sugars to acetic acid, it is imperative to have an appropriate balance of sugars in a hydrolysate. Hence, the choice of lignocellulosic biomass and steam pretreatment design are fundamental steps for the industrial application of this process.
KeywordsAcetic acid Lignocellulosic sugars Moorella thermoacetica Steam explosion
This research was supported by US Department of Agriculture with funding from Agriculture and Food Research Initiative (USDA AFRI Grant 2011-68005-30407). We would like to thank University of Washington-Denman Professorship funds in Bioresource Engineering as well as Biofuels and Bioproducts Laboratory Research Group. Our special thanks to Dr. Shannon Ewanick, Dr. Rodrigo Morales, and Naila Ribeiro Mori for providing hydrolysates, and undergraduate student, Mencius Leonard.
- 6.BBI International (2015) U.S. Ethanol Plants. Available via DIALOG. http://www.ethanolproducer.com/plants/listplants/US/Existing/All. Accessed 13 Mar 2015
- 7.Bloomberg (2015) Bloomberg database terminal. [Online]. Available at: Subscription Service. Accessed 13 Mar 2015Google Scholar
- 8.Bock SA, Fox SL, Gibbons WR (1997) Development of low cost, industrially suitable medium for the production of acetic acid from Clostridium thermoaceticum. Biotechnol Appl Biochem 25:117–125Google Scholar
- 12.Clark B (2015) Chemical profile. US acetic acid. ICIS Chem Bus 287(9):34Google Scholar
- 13.Dowe N, McMillan J (2008) SSF experimental protocols-lignocellulosic biomass hydrolysis and fermentation laboratory analytical procedure (LAP) NREL/TP-510-42630Google Scholar
- 14.DTN/The Progressive Farmer (2015) Daily ethanol rack price. Available via DIALOG. http://www.dtnprogressivefarmer.com/dtnag/renewable-fuels. Accessed 13 Mar 2015
- 19.Grand View Research I (2015) Acetic acid market analysis by application (VAM, acetic anhydride, acetate esters, PTA) and segment forecasts to 2022. Available via DIALOG. http://www.grandviewresearch.com/industry-analysis/acetic-acid-market. Accessed 1 Aug 2015
- 28.Ounine K, Petitdemange H, Raval G, Gay R (1985) Regulation and butanol inhibition of d-xylose and d-glucose uptake in Clostridium acetobutylicum. J Appl Environ Microbiol 49:874–878Google Scholar
- 39.Waterhous A (2012) Folin-Ciocalteau Micro Method for Total Phenol in Wine. Available via DIALOG.http://waterhouse.ucdavis.edu/faqs/folin-ciocalteau-micro-method-for-total-phenol-in-wine. Accessed 4 Mar 2014
- 41.Yoneda N, Kusano S, Yasui M, Pujado P, Wilcher S (2001) Recent advances in processes and catalysts for the production of acetic acid. Appl Catal A Gen 221:253–265 (Published by Elsevier Science B.V.) Google Scholar