为了提高海洋细菌L1-9菌株液体发酵的生物量和抑菌活性,进行了50 L发酵罐的分批发酵和补料发酵工艺研究。结果表明:L1-9菌株在50 L发酵罐中分批发酵工艺为:接种量8%(菌龄24 h、浓度为109个细胞/mL)、初始搅拌速度250 r/min、通气量为3 L/min,发酵时间为11～12 h,生物量达2.40×1010CFU/mL;补料分批发酵工艺为:在分批发酵的条件下,发酵13 h开始流加60 g/L葡萄糖溶液,使还原糖浓度保持在0.4 g/L左右,发酵周期30 h,生物量达到4.63×1010CFU/mL,比分批发酵提高了78.07%;抑菌时效测定结果表明,发酵液对金黄色葡萄球菌(Staphylococcus aureus)的抑菌作用伴随着生物量的增加不断加强,20 h抑菌活性达到高峰,抑菌带宽度为17.75 mm,抑菌活性与生物量呈正相关,为生长关联型。

To higher biomass and antimicrobial activities of marine bacteria Paenibacillus polymyxa L1-9 in a 50 L fermenter,the technological processes were optimized with batch and fed-batch fermentation.The result showed that the best process for batch fermentation was following.Inoculum size was 8 % with culturing after 24 h and cell concentration was 109 cell/mL.Initial rotating speed and ventilator capacity were 250 r/min and 3 L/min respectively.The max biomass,2.40×1010 CFU/mL,was achieved after 11~12 h fermentation.For fed-batch process,the max biomass,4.63×1010 CFU/mL,was obtained after 30 h.This result was based on keeping 0.4g/ L reducing sugar in medium by adding 6g/L glucose after 13h growing.Comparing to batch fermentation,fed-batch fermentation yielded increasing 78.07% products.The antimicrobial activity of L1-9 to Staphlococcus aureaus was tested here.There was an ascending trend when the biomass increased.The activity reached its top at 20h when the inhibition zone was 17.75 mm.The conclusion is that there is a positive correlation between antimicrobial activity and biomass of L1-9 and it is a growth associated strain.