Carbohydrate Hydrolytic Activity, Antibiotic Resistance and Stress Tolerance ofLacticaseibacillus paracaseiBCRC-16100 andLacticaseibacillus paracaseiZFM54 for Probiotics Using Genomic and Biochemical Approaches

Abstract

Probiotics are live microorganisms infused in food products or beverages that offer several health benefits in the body including acceleration of nutrient digestion and improvement of gut microbiota. In addition to the potential health benefits, it is also essential to ensure the safety of probiotics incorporated in food. Here, we present evidence of the ability of two probiotic isolates, Lacticaseibacillus paracasei BCRC-16100 and Lacticaseibacillus paracasei ZFM54, in the (1) enhancement of carbohydrate digestion, (2) tolerance to a range of drug and food processing conditions, and (3) antibiotic resistance and finally propose corresponding molecular mechanisms. Approaches include predictions using whole genome sequence (WGS) analysis, carbohydrate hydrolytic activity, and antibiotic resistance. WGS predictions suggested the ability of the two isolates to increase digestion of macronutrients particularly starch and antibacterial activity against opportunistic pathogens. The ability to facilitate carbohydrate hydrolysis was confirmed through a biochemical assay where the two isolates when grown alongside with starch causes release of glucose. However, the two isolates did not show antibacterial activities against pathogenic S. aureus, S. epidermidis, E. coli, E. faecalis, and P. aeruginosa. In terms of safety, WGS revealed the presence of antibiotic resistance (AbR) genes with different mechanisms, permease, and efflux pump, contributing to multidrug resistance in both isolates which were validated by their resistance against six (6) antibiotics including gentamicin, clindamycin, erythromycin, streptomycin, ofloxacin and vancomycin at 24 hours but susceptibility at 48 hours was observed in five (5) antibiotics except vancomycin. Furthermore, promoter and transposable element analysis showed the most active and highly transferable AbR genes in each of the isolates. Altogether, we show the potential of two probiotic isolates to be incorporated in food products for improved carbohydrate digestion and the need to address the removal of active and mobile antibiotic resistance genes that may compromise safety.