关键词: 青海茶卡盐湖, 嗜盐真菌, 分离筛选, 纤维素酶, 酶学性质

Abstract: To obtain halophilic cellulase-producing fungi from the Chaka Salt Lake, Qinghai Province, PDA medium containing 5% NaCl was used as an isolation medium to obtain halophilic fungi strains. After initial screening with sodium carboxymethyl cellulose (CMC) as the only carbon source, the enzyme properties of cellulase produced by high-activity strains were studied by Congo red plate. The results showed that 24 strains of cellulose-degrading bacteria were obtained from the samples of Chaka Salt Lake, which belonged to 10 different genera. A highly active strain was obtained by primary screening and rescreening, named DaliF28, and identified asCladosporiumsp. by ITS gene. After 32 hours of liquid fermentation and culture ofCladosporiumsp. DaliF28, the cellulase activity in the supernatant reached a maximum of 32.87 U/mL. The optimum temperature, pH, and salt concentration of cellulases produced byCladosporiumsp. DaliF28 were 50 ℃, 6.6, and 2.5 mol/L NaCl, respectively. It remained above 60% relative activity after incubated at the optimum pH and salt concentration at 60 ℃ for 1 h, and still exhibited more than 60% relative activity at the concentration of 0－4 mol/L NaCl. The isolated strains indicated that there are abundant halophilic cellulase-producing fungi in Chaka Salt Lake.

Key words: Qinghai Chaka Salt Lake, halophilic fungi, isolation and screening, cellulase, enzymatic properties