陈化烟叶中1株果胶酶高产菌的分离、筛选与鉴定

烤烟中的高果胶含量严重影响烟草吸食品质和陈化速度。为降低烟草中的果胶含量,提高烟草及烟草制品的品质及安全性,从不同年份和不同产地的18份复烤烟草中共分离筛选出有降解果胶能力的细菌38株和真菌9株。其中,XC-8、XC-30、SMXP-57、SMXP-58、SMXP-62共5株细菌具有较高的降解果胶的能力,在发酵时间24 h、发酵温度30℃、接种量10%条件下果胶酶活性分别为176、179、143、192、121 U/mL。其中,菌株SMXP-58酶活性最高(192 U/mL),通过16S r DNA序列分析并结合形态、理化特性分析,确定SMXP-58菌株为枯草芽孢杆菌(Bacillus subtilis)。将SMXP-58菌株制成的菌剂(9.6×107个/mL)喷施于100 g烟叶表面,发酵3 d的烟叶评吸总分提高了1.02,进一步优化发酵条件,在发酵时间60 h、菌液量1 mL、水量20 mL的条件下,烟叶中果胶含量最低(7.45%)。

Isolation,Screening and Identification of A High Pectinase-producing Bacterial Strain from Aging Tobacco Leaf

The amount of pectin in flue-cured tobacco seriously influences the qulity and aging speed of tobacco. In order to decrease the pectin content in flue-cured tobacco,improve the quality and safety of flue-cured tobacco,38 bacterial strains and 9 fungi strains which could degrading the pectin were isolated from 18 kinds of flue-cured tobacco from different years and different origins. The bacterial strains XC-8,XC-30, SMXP-57,SMXP-58,SMXP-62 possessed higher ability of degrading pectin substance,and their enzymatic activity were 176,179,143,192,121 U/mL when the culture period was 24 h at the temperature of 30 ℃and innoculation amount of 10%. Strain SMXP-58 possessed the highest enzymatic activity ( 192 U/mL ) , which was identified as Bacillus subtilis based on 16S rDNA sequence analysis and morphological, physichemical characters analysis. Total score of smoking increased by 1. 02 after spraying the bacterial agent(9. 6 × 107 bacteria per milliliter) made from SMXP-58 on the 100 g tabacco. Tobacc pectin was the least with 7. 45% under the conditions of fermenting 60 h,bacterial agent 1 mL,water 20 mL.