Screening and identification of Aureodacidium spp. and the effect of dissolved oxygen on fermentation

The Aureodacidium spp. were isolated and screened out from outdoors. After plate screening,shake flask re-screening,molecular biology identification,the ipe-3(GenBank accession number is KY618121)was identified as Aureobasidium pullulans,ipe-5(GenBank accession number is KY621468)identified as Aureobasidium spp. Ipe-3 and ipe-5 were fermented by 2.7 L fermenter respectively. The results showed that the yield of poly malic acid and malic of strain ipe-3 were 10.027 g/L and 5.7 g/L. The yield of poly malic acid of strain ipe-5 was 0.3 g/L and the maximum yield of malic acid was 57.24 g/L. The effects of dissolved oxygen on the fermentation yield of Aureodacidium spp. were studied. Compared with the yield under 70% dissolved oxygen,in 10% dissolved oxygen condition,the yield of poly malic acid and malic acid of strain ipe-3 were decreased by 41.67% and 62.63% respectively. The yield of malic acid of ipe-5 decreased by 83.05%,and without poly malic acid produce in 10% dissolved oxygen condition. The results showed that the decrease of dissolved oxygen led to the drop of biomass and the rate of glucose utilization,which cause Aureodacidium spp. produced less acid.