Gas-Forming Nonstarter Lactorbacilli
نویسندگان
چکیده
An obligatory heterofermentative lactic acid bacterium Lactobacillus wasatchii sp. nov. isolated from gassy Cheddar cheese was studied for growth, gas formation, salt tolerance and survival against pasteurization treatments at 63°C and 72°C. Initially, Lb. wasatchii was thought to only use ribose as a sugar source and we were interested in whether it could utilize galactose. Experiments to determine rate and extent of growth and gas production in carbohydrate restricted (CR) de Man, Rogosa, and Sharpe (MRS) medium under anaerobic conditions with various combinations of ribose and galactose at 12, 23, and 37°C were conducted with 23°C being the more optimum growth temperature of Lb. wasatchii. When grown on ribose (0.1%, 0.5%, and 1%), maximum specific growth rates (μmax) within each temperature were similar. When galactose was the only sugar, μmax was 2 to 4 times lower than with ribose. At all temperatures, highest final cell densities (OD640) of Lb. wasatchii were achieved in CR-MRS plus 1% ribose, 0.5% ribose and 0.5% galactose, or 1% ribose combined with 1% galactose. Similar μmax values 1 The name of this bacterium was subsequently revised to Lactobacillus wasatchensis.
منابع مشابه
Growth and gas formation by Lactobacillus wasatchensis, a novel obligatory heterofermentative nonstarter lactic acid bacterium, in Cheddar-style cheese made using a Streptococcus thermophilus starter.
A novel slow-growing, obligatory heterofermentative, nonstarter lactic acid bacterium (NSLAB), Lactobacillus wasatchensis WDC04, was studied for growth and gas production in Cheddar-style cheese made using Streptococcus thermophilus as the starter culture. Cheesemaking trials were conducted using S. thermophilus alone or in combination with Lb. wasatchensis deliberately added to cheese milk at ...
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