BioChem - DOS

Closing the carbon balance for fermentation by Clostridium thermocellum (ATCC 27405)

Bioresource technology : biomass, bioenergy, biowastes, conversion technologies, biotransformations, production technologies

Ellis, Lucas D.; Holwerda, Evert K.; Hogsett, David; Rogers, Steve; Shao, Xiongjun; Tschaplinski, Timothy; Thorne, Phil; Lynd, Lee R.

<P><B>Highlights</B></P><P>&#x025BA; <I>Clostridium thermocellum</I> consistently demonstrates poor carbon recovery. &#x025BA; A carbon balance revealed >10% of substrate carbon in liquid phase in the form of unidentified compounds. &#x025BA; The unidentified carbon was made up of low molecular weight compounds including pyruvate, malate and free amino acids.</P> <P><B>Abstract</B></P><P>Our lab and most others have not been able to close a carbon balance for fermentation by the thermophilic, cellulolytic anaerobe, <I>Clostridium thermocellum.</I> We undertook a detailed accounting of product formation in <I>C. thermocellum</I> ATCC 27405. Elemental analysis revealed that for both cellulose (Avicel) and cellobiose, <U>></U>92% of the substrate carbon utilized could be accounted for in the pellet, supernatant and off-gas when including sampling. However, 11.1% of the original substrate carbon was found in the liquid phase and not in the form of commonly-measured fermentation products &ndash; ethanol, acetate, lactate, and formate. Further detailed analysis revealed all the products to be <720da and have not usually been associated with <I>C. thermocellum</I> fermentation, including malate, pyruvate, uracil, soluble glucans, and extracellular free amino acids. By accounting for these products, 92.9% and 93.2% of the final product carbon was identified during growth on cellobiose and Avicel, respectively.</P>

2012

0960-8524

103

1

pp.293-299

10.1016/j.biortech.2011.09.128

http://click.ndsl.kr/servlet/OpenAPIDetailView?keyValue=05787966&target=NART&cn=NART57989485

Clostridium thermocellum; Carbon; Mass balance; Consolidated bioprocessing