Isolation, Identification and Analysis of Growth Characteristics of Functional Potential Fungi from Tibetan Traditional Air-Dried Yak Meat

Fungi with bioactive potential were isolated from Tibetan traditional air-dried yak meat. The stains were identified by morphological observation, physiological and biochemical analysis, ITS sequence analysis, functional potential and growth characteristics including protease and lipase production, tolerance to NaCl and NaNO₂ and acid resistance. The results showed that five strains were isolated from samples collected from six Tibetan regions, including two strains of Kluyveromyces marxianus (B2, sn), two strains of Saccharomycopsis fibuligera (C-2, C-7) and one strain of Candida zeylanoides (M1-3). Among them, M1-3, B2 and C-2 had strong protease and lipase production abilities. They could ferment glucose, sucrose lactose and tolerate 8.0% NaCl with 250 mg/kg NaNO₂. They can grow at pH values between 3.0~6.0. However, the growth of stains was continuously inhibited with the decreasing pH, and the optimum pH ranged from 5.0 to 6.0. In addition, there was no antagonistic effect among the three strains and they could coexist well. These three stains had a certain antibacterial effect on Bacillus toyonensis, Pseudomonas lundensis and Aspergillus niger, which indicates they arebioactive potential stains with good growth abilities. The results provide a theoretical basis for the isolation and screening of functional strains in Tibentan air-dried yak meat and the development of fermentation agents.