Kotarski S F, Salyers A A
J Bacteriol. 1981 Jun;146(3):853-60. doi: 10.1128/jb.146.3.853-860.1981.
We investigated the ability of Bacteroides thetaiotaomicron, an obligate anaerobe from human colonic microflora, to grow in a carbohydrate-limited continuous culture at generation times ranging from 3.5 to 28 h per division. Four carbohydrates were tested: glucose, N-acetylglucosamine, glucuronic acid, and glucosamine. At a generation time of 3.5 h per division, the growth yields for bacteria growing on glucose, N-acetylglucosamine, and glucuronic acid were 76, 68, and 50 g of cells (dry weight) per mol of substrate, respectively. Growth yields at 28 h per division were 61, 52, and 37 g/mol of substrate, respectively. When glucosamine was the carbohydrate source, a stable population of bacteria was attainable only at generation times longer than 12 h per division. Growth yields at 15 and 32 h per division were 11 and 33 g/mol of substrate, respectively. There was no significant variation with increasing generation times in the specific activities of selected glycolytic enzymes, of disaccharidases such as alpha- and beta-glucosidases and alpha- and beta-galactosidases, or of the polysaccharidase chondroitin sulfate lyase. By contrast, the pattern of fermentation products varied with both the generation time and the carbon source. At a generation time of 3.5 h per division, the main products from the fermentation of glucose were acetate and succinate, with a trace of propionate. At 28 h per division, propionate concentrations were higher and succinate concentrations were lower than at 3.5 h per division. The products from the fermentation of glucosamine were the same as those from glucose fermentation. However, when N-acetylglucosamine was fermented, the concentration of acetate was much higher at all generation times than when glucose was the carbon source. When glucuronic acid was the carbon source, acetate was the main fermentation product, and only traces of propionate and succinate were detected. Another characteristic that varied with the growth rate was the ability of B. thetaiotaomicron to produce the inducible enzyme alpha-glucosidase when exposed to maltose. The ability of the organism to produce this enzyme declined with increasing generation times.
我们研究了来自人类结肠微生物群的专性厌氧菌——多形拟杆菌在碳水化合物受限的连续培养中，在每代3.5至28小时的代时范围内生长的能力。测试了四种碳水化合物：葡萄糖、N-乙酰葡糖胺、葡糖醛酸和葡糖胺。在每代3.5小时的代时，以葡萄糖、N-乙酰葡糖胺和葡糖醛酸为底物生长的细菌的生长产量分别为每摩尔底物76、68和50克细胞（干重）。每代28小时时的生长产量分别为每摩尔底物61、52和37克。当葡糖胺作为碳水化合物来源时，只有在每代长于12小时的代时才能获得稳定的细菌群体。每代15小时和32小时时的生长产量分别为每摩尔底物11克和33克。所选糖酵解酶、二糖酶（如α-和β-葡糖苷酶以及α-和β-半乳糖苷酶）或多糖酶硫酸软骨素裂解酶的比活性，不会随着代时增加而有显著变化。相比之下，发酵产物的模式随代时和碳源而变化。在每代3.5小时的代时，葡萄糖发酵的主要产物是乙酸盐和琥珀酸盐，有微量丙酸盐。在每代28小时时，丙酸盐浓度较高，琥珀酸盐浓度低于每代3.5小时时。葡糖胺发酵的产物与葡萄糖发酵的产物相同。然而，当发酵N-乙酰葡糖胺时，在所有代时乙酸盐的浓度都比以葡萄糖为碳源时高得多。当葡糖醛酸作为碳源时，乙酸盐是主要发酵产物，仅检测到微量的丙酸盐和琥珀酸盐。另一个随生长速率变化的特征是，多形拟杆菌在接触麦芽糖时产生诱导酶α-葡糖苷酶的能力。该生物体产生这种酶的能力随着代时增加而下降。
