Pectinolytic activity ofClostridium thermocellum: Its use for anaerobic fermentation of sugar beet pulp

Abstract

Summary. Clostridium thermocellum is well known for its ability to convert cellulose into ethanol and to hydrolyse hemicellulose. The present work shows its ability to hydrolyse model pectins and to use them for growth. The main products on these substrates as well as on sugar beet pulps were as follows: acetate, ethanol and methanol. Galacturonase and lyase activities were measured in the fermentation broths. As shown by the accumulation of methanol in the "medium, there is a pectin esterase activity but this one seems to be very low.

Cellulase, Clostridia, and Ethanol

“…C. thermocellum also possesses at least six xylanases (107,232), two lichenases (367), two laminarinases (332), and minor activities of ␤-xylosidase, ␤-galactosidase, and ␤-mannosidase (164). A strain of C. thermocellum has been shown to degrade pectin and probably produces pectin lyase, polygalacturonate hydrolase, and pectin methylesterase (314). We found the activity responsible for hydrolysis of crystalline cellulose, unlike the endoglucanases, to be inhibited by cellobiose (141); glucose had no such inhibitory effect.…”

Involvement of an Intracellular Oligogalacturonate Hydrolase in Metabolism of Pectin by Clostridium thermosaccharolyticum

“…C. thermosaccharolyticum was unable to produce or consume galacturonate, a phenomenon which was observed earlier with other pectin-degrading bacteria, such as C. thermosulfurigenes, C. rubrum, C. thermocellum, and Bacteroides pectinophilus (12,20,24,27). The dimer and trimer, therefore, seem to be taken up by the cell.…”

Hydrolysis of beet pulp polysaccharides by extracts of solid‐state cultures of Pencicillium capsulatum

“…Nevertheless, various organisms including Aeromonas hydrolphilia, Bacillus macerans, Clostridium thermosaccharolyticum, Fusarium oxysporum, Pachysolen fannophilus, and Trichosporon spp, can convert various hexoses and pentoses to ethan01.~'-~~ In addition to various hexoses and pentoses, pectin andlor its breakdown products can be fermented to alcohol by Clostridium thermohydrosulphuricum and Thermoanaerobacter ethanolicus2* while pectin may also be fermented by Clostridium thermocellum. 26 For reasons that are evident from the earlier discussion, it is possible, as indeed it has been suggested for other case^,'^,*^ that the overall yield of ethanol from beet pulp could be enhanced if the sugar endproducts, inhibitors of saccharification, were converted to ethanol and the latter, an inhibitor of saccharification and fermentation, were continuously removed.…”