ABSTRACT
In this study, Lacticaseibacillus casei NCIM 5752, a new isolate has been explored for probiotic properties and has shown significant bile salt hydrolase activity and cholesterol-reducing activity (56.7 ± 0.27%) in the presence of bile salts. It also tested negative for the production of lecithinase and gelatinase, indicating its non-pathogenic nature. The test strain was able to tolerate pH of 2.0 and 3.0 with 63.42 and 94.7% of the cells survived after 3 h. L. casei showed auto-aggregation of 85.3% and surface hydrophobicity of 22.5% in xylene and 19.4% in hexane. Paneer whey was explored as a basic raw material for alternative media formulation for growing lactic acid bacteria. Paneer whey was found to contain lactose (4.15%), protein (0.42%), and rich in mineral content. Response surface methodology was employed to optimize the medium composition with three independent variables yeast extract (X1), dextrose (X2), and dipotassium hydrogen phosphate (X3), and the response-Y was set to biomass obtained in terms of log CFU/ml. They were supplemented to paneer whey medium for growing this strain. The second-order polynomial regression model predicted that the maximum cell mass production of 11.30 ± 0.5 log CFU/ml at optimal composition of 16.22 g/L of yeast extract, 19.31 g/L of dextrose, and 2.12 g/L of dipotassium hydrogen phosphate in paneer whey medium. Experiments were conducted to validate the RSM results, and the biomass achieved was 11.27 ± 0.50 log CFU/ml, which is in close agreement with the yield predicted by the RSM. By applying the fermentation strategy, the biomass was increased to 5.56 ± 0.34 g/L dry cell weight corresponding to 11.58 ± 0.24 log CFU/ml. The newly optimized media was significantly cost-effective and produced 26.45% more biomass than the conventional MRS media. This optimized media may find application for the large-scale biomass production of probiotics. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-023-03899-z.
