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培养液的初始 p H值直接影响 B- 90 3菌株的生长繁殖 ,从而对其抗菌物质的产生和积累产生重要影响。 p H值小于 5时 ,不利于细菌生长繁殖 ,滤液中抗菌物质活性弱 ;p H值在 6～ 8时有利于细菌的增殖 ,抗菌活性亦最强。培养过程中供氧条件与菌体繁殖和抑菌活性呈正相关 ,而培养液初始接菌量高时可缩短抗菌物质出现的时间。基本营养物质的初步筛选试验证明 :大米粉、豆饼粉、麦麸、酵母粉和 Ca CO3 及 KH2 PO4是发酵培养基中最佳的营养物质 ,可满足抗菌物质产生对碳、氮和矿物质的营养需求。B- 90 3的发酵过程可分为两个阶段 :在 30℃下 ,2 4小时内 ,细菌数量达最大值 ,p H值由低向高变化 ,但此阶段检测不出抗菌物质的活性 ;第二阶段 ,培养 41小时后 ,抗菌物质活性开始显露 ,至 112小时后达最大值 ,p H值也逐渐由高变低。培养过程中 ,p H值的变化对细菌繁殖和抗菌物质的产生与积累有明显的伴随关系
The initial pH value of the culture medium directly affects the growth and reproduction of the B-903 strain, which has a significant impact on the generation and accumulation of antibacterial substances. When p H value is less than 5, it is not conducive to bacterial growth and reproduction, and antibacterial substance activity in the filtrate is weak; p H value is beneficial to the proliferation of bacteria at 6 to 8, and antibacterial activity is the strongest. During culture, the oxygen supply condition was positively correlated with the growth and antibacterial activities of bacteria, while the initial bacterial inoculation rate could shorten the time of emergence of antibacterial substances. The preliminary screening experiments of basic nutrients proved that rice flour, bean cake flour, wheat bran, yeast extract and CaCO3 and KH2 PO4 were the best nutrients in the fermentation medium to meet the requirements of antimicrobial substances for carbon, nitrogen and minerals Nutritional needs. The fermentation process of B-903 can be divided into two stages: the number of bacteria reached the maximum within 24 hours at 30 ° C, and the value of p H changed from low to high, but the activity of antibacterial substance could not be detected at this stage; In the second phase, after 41 hours of cultivation, the antibacterial substance activity began to be revealed, reaching the maximum value after 112 hours, and the value of p H gradually decreased from high to low. In the process of culture, the change of p H value has obvious concomitant relationship with the growth of bacteria and the production and accumulation of antibacterial substances