Differential fermentation of celluose allomorphs by ruminal cellulolytic bacteria

In addition to its usual native crystalline form (cellulose I), cellulose can exist in a variety of alternative crystalline forms (allomorphs) which differ in their unit cell dimensions, chain packing schemes, and hydrogen bonding relationships. We prepared, by various chemical treatments, four diff...

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Bibliographic Details
Published inApplied and environmental microbiology Vol. 57; no. 11
Main Authors Weimer, P.J. (U.S. Dairy Forage Research Center, ARS, USDA, Madison, WI), French, A.D, Calamari, T.A. Jr
Format Journal Article
LanguageEnglish
Published 01.11.1991
Subjects
BACTERIA
BACTEROIDES
CELLULOLYSE
CELLULOSE
CELULOLISIS
CELULOSA
FERMENTACION
FERMENTATION
JUGOS DIGESTIVOS
MICROORGANISME
MICROORGANISMOS
PEPTOCOCCACEAE
POLIMORFISMO
POLYMORPHISME
RUMEN
SUC DIGESTIF
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Summary:In addition to its usual native crystalline form (cellulose I), cellulose can exist in a variety of alternative crystalline forms (allomorphs) which differ in their unit cell dimensions, chain packing schemes, and hydrogen bonding relationships. We prepared, by various chemical treatments, four different alternative allomorphs, along with an amorphous (noncrystalline) cellulose which retained its original molecular weight. We then examined the kinetics of degradation of these materials by two species of ruminal bacteria and by inocula from two bovine rumens. Ruminoccus flavefaciens FD-1 and Fibrobacter succinogenes S85 were similar to one another in their relative rates of digestion of the different celluloses, which proceeded in the following order: amorphous III(I) IV(I) III(II) I II. Unlike F. succinogenes, R. flavefaciens did not degrade cellulose II, even after an incubation of 3 weeks. Comparisons of the structural features of these allomorphs with their digestion kinetics suggest that degradation is enhanced by skewing of adjacent sheets in the microfibril, but is inhibited by intersheet hydrogen bonding and by antiparallelism in adjacent sheets. Mixed microflora from the bovine rumens showed in vitro digestion rates quite different from one another and from those of both of the two pure bacterial cultures, suggesting that R. flavefaciens and F. succinogenes (purportedly among the most active of the cellulolytic bacteria in the rumen) either behave differently in the ruminal ecosystem from the way they do in pure culture or did not play a major role in cellulose digestion in these ruminal samples
Bibliography:L51
9172411
ISSN:0099-2240
1098-5336