烟叶中高产果胶酶菌株的筛选及酶学性质
Screening of Highly Pectinase-Producing Strain from Tobacco Leaf and Enzymatic Properties Thereof
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摘要: 以74份醇化片烟样品和8份把烟样品为材料,采取稀释涂布平板法分离烟叶中的细菌和真菌,通过透明圈法和发酵液果胶酶活性测定法筛选酶活较高的菌株,并对高产果胶酶菌株进行了鉴定和酶学性质的初步研究。结果表明:在分离得到的389株细菌和81株真菌中,筛选出产果胶酶细菌60株、真菌21株,其中菌株TS63-9的果胶酶活性最高,达142.43 U/mL,根据形态学特征和ITS序列分析,将其初步鉴定为疣孢青霉(Penicillium verruculosum);TS63-9果胶酶的最适催化温度为55℃,在40℃条件下保温4 h后仍有73.9%的活性,最适反应pH为4.0,在pH 4.0~6.0之间酶稳定性较好。Abstract: Seventy-four samples of aged tobacco strips and 8 samples of bundle leaf were collected to isolate bacteria and fungi with plate method,and strains with higher enzymatic activity were screened by transparent loop method and assay of pectinase activity in fermentation liquid. The screened strains were identified with morphological characteristics and molecular technique,and its enzymatic properties were preliminarily studied. The results showed that 60 strains and 21 fungi were screened from 389 isolated strains and 81 fungi,among them, strain TS63-9 possessed the highest pectinase activity of 142.43 U/mL, which was identified as Penicillium verruculosum according to its morphological characteristics and ITS rDNA sequence analysis. The optimal catalytic temperature for TS63-9 pectinase was 55℃,and 73.9% of its maximum activity still retained after incubation for 4 hours at 40℃. The preferable reaction pH was 4.0,and held good enzymatic stability in the pH range of 4.0 and 6.0.
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