Article Abstract:
The isolated mutant strains defective in peptidase activity have one-tenth of the enzyme activity responsible for cleavage of glycine-arginine-4-methoxy-beta-naphthylamide (Gly-Arg-MNA). A concomitant loss in the activity against arginine-Arg-MNA exists and both are affected by proteinase inhibitors. Similar growth rates are observed in wild-type and mutant strains grown in batch culture with various nitrogen sources. However, Gly-Arg-MNA leads to ammonia-producing ruminal bacteria whose rate and extent is reduced by 25% in cocultures containing the mutants.
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Article Abstract:
The effects of vitamin B12 on propionate formation and yield by Prevotella ruminicola 23 were examined. Acetate and succinate were the major fermentation products in batch culture in the absence of vitamin B12. On the other hand, propionate and succinate were the predominant fermentation products in continuous culture in the presence of vitamin B12 at low and high dilution rates, respectively. Thus, propionate production, which required vitamin B12, could be an energy conservation mechanism.
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Article Abstract:
The Prevotella ruminicola gene coding for carboxymethyl cellulase (CMCase) was fused to the Thermomonospora fusca gene coding for the E2 cellulose-binding domain. The resulting hybrid enzyme was purified and characterized. The results showed thatthe recombinant enzyme could bind efficiently to cellulose, without alterationsin enzyme activity. In addition, the enzyme displayed activity on both swollen and ball-milled celluloses.
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