| 摘要 |
<p>The cultivation of proprietary and genetically altered strains of Lactobacillus casei subspecies rhamnosus in the presence of Veilonella criceti in a medium containing a fermentable carbohydrate results in the production of propionate, acetate, carbon dioxide and hydrogen. In the absence of either strain, carbohydrates are generally not fermented to propionate. Under optimum fermentation conditions lactate, the major product of carbohydrate metabolism of L. casei, is rapidly metabolized to propionate, acetate, carbon dioxide and hydrogen by V. criceti and is present in the culture medium at a concentration less than 0.5 milligrams per milliliter. The yield of propionate produced is approximately 1.4 moles propionate per mole of fermentable monosaccharide or 2.8 mole per moles of fermentable disaccharide utilized. In addition to the propionate fermentation, lactate can be accumulated by blocking its conversion to propionate by the adjustment of the pH, temperature or degree of aeration of the fermentation medium. Thus a mixture of propionate, acetate and lactate can be efficiently produced from fermentable carbohydrates by the co-cultivation of these bacterial strains.</p> |
