Microencapsulation of riboflavin-producing Lactiplantibacillus Plantarum MTCC 25,432 and Evaluation of its Survival in Simulated Gastric and Intestinal Fluid

Characterization of probiotic strains of Bacillus sp. from fermented palm wine (Nypa fructicans sp.) and exploration of cellulolytic potential for use as an addition in animal feed

The main objective of this study was to assess cellulolytic probiotic strains from traditional fermented beverages such as palm wine in order to supplement the animal feed and strengthen the gut health of the animal for better digestibility and absorption. In the present study, different types of microbes were isolated from traditionally prepared palm wine and analyzed for their probiotic nature. For any microbe to be probiotic in nature, it has to sustain the harsh conditions of the human gastrointestinal tract such as acid tolerance, bile tolerance at the lower range of pH, and other properties like auto aggregation test, cell surface hydrophobicity test with non-polar hydrocarbons for evaluating its capabilities to adhere to the intestinal cells and antimicrobial nature against pathogens. Bacillus mycoides strain PR04 and Bacillus subtilis strain PR21 were found to be resistant to acid and bile in simulated artificial gastrointestinal tract model, found to be than 55% hydrophobic with xylene and n-hexadecane and also showed antimicrobial activity greater towards pathogenic strains like Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans, and Salmonella typhimurium respectively. The cellulolytic activity of the isolates PR04 and PR21 was evaluated in (0.2-2) % CMC (carboxymethyl cellulose) plate. Bacillus mycoides PR04 and Bacillus subtilis PR21 could degrade carboxymethyl cellulose, filter paper, and sugarcane bagasse. The degradation of sugarcane bagasse was confirmed by Scanning electron microscopy and filter paper degradation after 4 days of incubation at 37 °C. Cellulase gene of the identified Bacillus sp. strains was amplified by primers CF5'-ACAGGATCCGATGAAAACGGTCAATTTCTATTTT-3' and CR5'-ACTCTCGAGATTGGGTTCTGTTCCCAAT-3'. This study proposes potential probiotic Bacillus mycoides PR04 (Accession no. OR625070) and Bacillus subtilis PR21 (Accession no. OR625072) in the application as an animal feed additive to assist in its digestibility and encourage the gut health.

Development of whey protein beverage incorporating encapsulated probiotic strain Lactiplantibacillus rhamnosus NCDC 347 and its physico-chemical characteristics

In the present study, encapsulated strain Lactiplantibacillus rhamnosus NCDC 347 was used to prepare a novel whey protein-based beverage. The encapsulation process utilized skimmed milk powder matrix and evaluated strain viability, physico-chemical properties, sensory assessment, and shelf-life stability. Encapsulated L. rhamnosus NCDC 347 within skim milk powder maintained viability at 8.0 log CFU/g, forming spherical microcapsules with 1-12 µm concavities. Probiotic addition to whey protein beverages maintained pH and acidity within desired ranges. Physico-chemical analysis showed protein content of 8.71 ± 0.21 % to 10.05 ± 0.42 %, fat content of 0.56 ± 0.24 % to 0.67 ± 0.13 %, viscosity of 5.14 pa/s, and total soluble solids (TSS) of 14.42 ± 0.31 to 16.16 ± 0.23° Brix. The shelf-life study revealed that the beverage remained stable for up to 90 days with no significant changes (p > 0.05) in sensory analysis. The sensory analysis scored the test sample's acceptability at 7.3 ± 0.41. The protein-rich probiotic drink exhibited favorable sensory qualities. Overall, incorporating encapsulated probiotic strain L. rhamnosus NCDC 347 into whey protein beverages could address daily protein requirements and enhance health.

Biological Characterization and Whole-Genome Analysis of Bacillus subtilis MG-1 Isolated from Mink Fecal Samples

Bacillus subtilis is an important part of the gut microbiota and a commonly used probiotic. In the present study, to assess the biological characteristics and probiotic properties of B. subtilis derived from mink, we isolated B. subtilis MG-1 isolate from mink fecal samples, characterized its biological characteristics, optimized the hydrolysis of casein by its crude extract, and comprehensively analyzed its potential as a probiotic in combination with whole-genome sequencing. Biological characteristics indicate that, under low-pH conditions (pH 2), B. subtilis MG-1 can still maintain a survival rate of 64.75%; under the conditions of intestinal fluid, gastric acid, and a temperature of 70 °C, the survival rate was increased by 3, 1.15 and 1.17 times compared with the control group, respectively. This shows that it can tolerate severe environments. The results of hydrolyzed casein in vitro showed that the crude bacterial extract of isolate MG-1 exhibited casein hydrolyzing activity (21.56 U/mL); the enzyme activity increased to 32.04 U/mL under optimized reaction conditions. The complete genome sequencing of B. subtilis MG-1 was performed using the PacBio third-generation sequencing platform. Gene annotation analysis results revealed that B. subtilis MG-1 was enriched in several Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathways, and most genes were related to Brite hierarchy pathways (1485-35.31%) and metabolism pathways (1395-33.17%). The egg-NOG annotation revealed that most genes were related to energy production and conversion (185-4.10%), amino acid transport and metabolism (288-6.38%), carbohydrate transport and metabolism (269-5.96%), transcription (294-6.52%), and cell wall/membrane/envelope biogenesis (231-5.12%). Gene Ontology (GO) annotation elucidated that most genes were related to biological processes (8230-45.62%), cellular processes (3582-19.86%), and molecular processes (6228-34.52%). Moreover, the genome of B. subtilis MG-1 was predicted to possess 77 transporter-related genes. This study demonstrates that B. subtilis MG-1 has potential for use as a probiotic, and further studies should be performed to develop it as a probiotic additive in animal feed to promote animal health.

Predictive Modeling of Riboflavin Production in Lactiplantibacillus plantarum MTCC 25432 Using Fuzzy Inference System

Riboflavin (Vitamin B2) is an essential vitamin and a microbial metabolite produced by some lactic acid bacteria (LAB). This investigation aims to study the overproduction of riboflavin in selected Lactiplantibacillus plantarum strain by using the one factor at a time (OFAT) tool coupled with the Fuzzy Inference System (FIS) and its validation through fermentative production in semi-defined media. Out of three Lactiplantibacillus strains used in this study, the maximum riboflavin producing strain was selected based on its ability to grow and produce higher levels of riboflavin. In results, Lactiplantibacillus plantarum strain MTCC 25432 was able to produce 346 µg/L riboflavin in riboflavin deficient assay medium and was investigated further. By using the OFAT-fuzzy FIS system, casamino acid in the range of 5-20 g/L, GTP 0.01-0.04 g/L, sodium acetate 5-15 g/L, and glycine 5-15 g/L were used to predict their effect on riboflavin production. The conditions optimized with modeling showed a 24% increment in riboflavin production (429 µg/L) by Lactiplantibacillus plantarum MTCC 25432 vis-a-vis the unoptimized counterpart (346 µg/L). In conclusion, an FIS-based predictive model was effectively implemented to estimate the riboflavin within an acceptable limit of 3.4%. Riboflavin production enhancing effects observed with various levels of sodium acetate, casamino acid, and GTP could be useful to re-design matrices for riboflavin production.