【摘要】 应用紫外线6、0Co辐照育种,选育出1株耐酸、耐氧的长双歧杆菌突变株GKSW1101。该菌株在pH4.5的液体培养基中,37.5℃培养24h,活菌数达到4.2×108cfu/mL。采用加碱中和保持培养液pH6.0~6.5进行发酵,在4℃、6000r/min离心15min收集菌体,添加脱脂奶粉、甘油、蔗糖,L-半胱氨酸盐酸盐为冷冻保护剂-,25℃冷冻保藏,制备成双歧杆菌冷冻浓缩发酵剂,活菌数达到2.4×1010cfu/g,-25℃贮存3个月后,活菌存活率为50%。更多还原

【Abstract】 An acid-and oxygen-resistant Bifidobacterium longum mutant strain GKSW1101 was obtained by UV and 60Co treatment.The cell density of mutant strain reached 4.2×108 cfu/ml when it was cultured in pH 4.5 liquid medium for 24 h at 37.5 ℃.The strain GKSW1101 was used for the production of freezing concentrated starters.During fermentation,6 mol/L NaOH was used to regulate the pH of medium,which was ranged between 6.0 and 6.5.After fermentation,the cells were collected by centrifugation at 6000 r/min and 4℃ for 15 min.Then,the skimmed milk powder,glycerol,sucrose and L-cysteine hydrochloride were added as protective additives for the freezing storage of strain GKSW1101 at-25℃.As freezing concentrated starter.After being stored at-25℃ for 3 months,the living cell count of the starter kept at 2.4×1010 cfu/g and the survival rate was 50%更多还原