微生物菌群之间配比协调关系的研究

对乳酸杆菌、乳酸球菌、枯草芽胞杆菌、酵母菌、大肠杆菌等菌种进行单独培养和不同比例的混合培养,测定了发酵过程中pH值、活菌数量及光密度的变化情况。结果表明,与含有25%混合菌液的发酵麸皮相比,含50%混合菌液的发酵麸皮,在发酵24 h后的需氧或厌氧活菌总数都有升高趋势(P>0.05),发酵1周后其pH值的下降趋势明显(P<0.05),说明乳酸菌数越多使pH下降越大。利用需氧(LB)和厌氧(MRS)培养液分别交叉培养需氧菌和厌氧菌,均能在相应的培养基上生长。充分说明厌氧菌和需氧菌混合培养在理论上是可行的。但是,如果用滤菌膜过滤后的培养过乳酸菌的MRS培养基来培养需氧菌时,这些菌种均不能在滤液中生长。

Study on the Proportion and Coordination of Microorganisms

Lactobacillus,Lactococcus,Bacillus subtilis,Yeast,E.coli were pure cultured and co-cultured to determine their proportion and coordination by estimating the changes of pH value,viable count and optical density.The results indicated that the aerobic or anaerobic viable colonies were increased(P<0.05) in fermented wheat bran mixed with 50% bacterium culture after 24h fermentation, compared with that in the wheat bran containing 25% bacterium culture.Their pH values dropped down after a week fermentation(P<0.05).The aerobic and anaerobic bacteria could grow in aerobic(LB) and anaerobic(MRS) media,indicateing that the mixed culture of aerobic and anaerobic bacteria was feasible theoretically.However,if the supernatant of Lactobacillus(passed through bacterium filter membrane to discard cell) was used to incubate aerobic bacteria,they could not grow.