The putrefaction of alkaline silica sol was investigated in this paper. The total colony numbers in three alkaline silica sol samples were 1.47 ×^ 105, 1.25× 10^4, and 9.45 × 10^4 cfu. mL 1, respectivel...The putrefaction of alkaline silica sol was investigated in this paper. The total colony numbers in three alkaline silica sol samples were 1.47 ×^ 105, 1.25× 10^4, and 9.45 × 10^4 cfu. mL 1, respectively. The salt- and alkalitolerant strains were isolated and selected using nutrient agar medium at 2.5% salinity and pH 9.5. Basic morphological, physiological and biochemical tests were conducted to confirm the preliminary characterizations of the strains. Based on API 50 CH test and 16S rDNA gene sequence analysis, the isolated strains were finally identified as Exiguobacterium aurantiacum, Cyclobacteriaceae bacterium, Microbacterium sp., Acinetobacter sp., Stenotrophomonas maltophilia and Bacillus thuringiensis. The survivability of the strains under different conditions such as salinities, acidities and temperatures was also studied. Some suitable methods for degerming, such as product pipe steam sterilization and regular canister cleaning, were proposed. To explore the possibility of isolates in industrial application, their alkaline protease and amylase production abilities were preliminarily studied. Five strains produced alkaline protease, whereas two strains produced alkaline amylase. Thus, understanding of the putrefaction on alkaline silica sol would be beneficial for improving industrial production.展开更多
文摘The putrefaction of alkaline silica sol was investigated in this paper. The total colony numbers in three alkaline silica sol samples were 1.47 ×^ 105, 1.25× 10^4, and 9.45 × 10^4 cfu. mL 1, respectively. The salt- and alkalitolerant strains were isolated and selected using nutrient agar medium at 2.5% salinity and pH 9.5. Basic morphological, physiological and biochemical tests were conducted to confirm the preliminary characterizations of the strains. Based on API 50 CH test and 16S rDNA gene sequence analysis, the isolated strains were finally identified as Exiguobacterium aurantiacum, Cyclobacteriaceae bacterium, Microbacterium sp., Acinetobacter sp., Stenotrophomonas maltophilia and Bacillus thuringiensis. The survivability of the strains under different conditions such as salinities, acidities and temperatures was also studied. Some suitable methods for degerming, such as product pipe steam sterilization and regular canister cleaning, were proposed. To explore the possibility of isolates in industrial application, their alkaline protease and amylase production abilities were preliminarily studied. Five strains produced alkaline protease, whereas two strains produced alkaline amylase. Thus, understanding of the putrefaction on alkaline silica sol would be beneficial for improving industrial production.
