Diversity Of Yeast And Evaluation Of Active Strains Of Erhai Lake And Yangzonghai Lake In Yunnan Province

There are nine plateau lakes in Yunnan province, and it located at>1400m a.s.l. Plateau Lake that means high altitude, low air pressure and oxygen content less is an environment of hypobaric hypoxia. Research of yeast about Plateau Lake is very important, it can provide theoretical basis for protection, development and utilization of yeast resources. At same time, it can provide species resource for the development of the biotechnology industry in Yunnan province and even the whole country. The aims of this study were to investigate yeast diversity in Erhai Lake and Yangzonghai Lake, and to explore the value of these yeasts in such ecological, and at same time, to analyze biological factors and abiotic factors on the influence of the yeast diversity.A total of278yeast strains were isolated from Erhai (162strain yeasts from lake water and sediment,116strain yeasts from surrounding environment), and identified as19genera and62species. Basidiomycetous yeast was predominant in all samples. The predominant genera in the basidiomycetous yeast were Cryptococcus and Rhodotorula. The predominant genus in the ascomycetous yeast was Candida. Rhodotorula glutinis (13.8%) and Rhodotorula mucilaginosa (13.8%) were the most frequently occurring species, followed by Cryptococcus magnus and Cryptococcus victoriae. A total of201yeast strains were isolated from Yangzonghai (172yeast strains from lake water,26yeast strains from sediment,3yeast strains from surrounding soil), and identified as15genera and48species. The tatol number of basidiomycetous yeasts and ascomycetous yeasts difference is not big. The predominant genus is Cryptococcus, Aureobasidiurn, Rhodotorula, Pichia. Aureobasidium pullulans, Pichia kudriavzevii, Rhodotorula mucilaginosa, Rhodotorula graminis were predominant species. Comparison of Erhai Lake and Yangzonghai Lake yeast diversity, only found13common species, respectively is Candida pseudolambica, Hanseniaspora uvarum, Pichia fermentans, Cryptococcus magnus, Cryptococcus albidus, Cryptococcus flavescens, Cryptococcus victoriae, Cryptococcus carnescens, Cryptococcus podzolicus, Rhodotorula glutinis, Rhodotorula mucilaginosa, Rhodotorula vanillica, Rhodosporidium diobovatum.Screening of all strains of extracellular enzymes and fats, the results showed that86strains produce extracellular enzymes activity and38strains yeasts have fat activity in159strains from Erhai Lake, and that32strains produce extracellular enzymes activity and85strains have fat activity in198strains from Yangzonghai Lake.Analyzed biological factors and abiotic factors on the influence of the yeast diversity, and found anthropogenic factor had influenced on yeast diversity, and then temperature, pH, conductivity, total nitrogen, total hardness, total organic carbon were also important factors for yeast diversity.