Previously, the exopolysaccharides produced by Lactiplantibacillus plantarum C7 isolated from the broiler intestine have been shown to possess probiotic potential. In this study, we highlighted the capacity of this strain to produce exopolysaccharide (EPS) endowed with several biological activities. The 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) free radical scavenging activities of EPS were found to be 30.4% and 68.165%, respectively, at 100 mg/mL. The ferrous reducing potential of EPS was measured to be 25.26%. Furthermore, EPS exhibited antibacterial effects against both Gram-negative and Gram-positive pathogens, including Escherichia coli ATCC 10536 and Bacillus cereus ATCC 11778, with inhibition zones of 22.5 ± 0.70 mm and 20 ± 1.41, respectively. On the other hand, the exopolysaccharide also exhibited excellent inhibitory activity against butyrylcholinesterase (BChE), achieving 70.99% inhibition at a concentration of 10 mg/mL. FTIR spectra were used to characterize functional groups in EPS. Our findings proved that EPS from Lactiplantibacillus plantarum C7 could be explored for various applications, particularly in the health and functional food sectors.

Attention to the association of cellulolytic bacteria with probiotic potential as an additive in animal feeding has risen in the last decades. Such additive use in livestock feed is essential in improving animal health, growth, and production performances. This study was designed to identify probiotic characteristics and test the cellulolytic ability of Bacillus strains isolated from the dromedary gastrointestinal tract. Thus, thirty-two Bacillus strains were tested for their cellulolytic ability on cellulose Congo-red agar media. Among the isolates, only the strain D1B3 showed the largest degradation zone (2.4 cm) and was identified as Bacillus amyloliquefacians by 16S rRNA gene sequence analysis. Solid-state fermentation (SSF) retained this strain for cellulase and biomass production using wheat bran as a substrate. The fermentation was optimized through a central composite design, by exploring three factors: incubation temperature, moisture ratio, and pH. Biomass and cellulose enzyme activity were selected as responses and corresponding regression coefficients were calculated. The optimal parameters were: liquid-to-solid ratio (1.19%), pH buffer (6.2), and incubation temperature (36.99 °C) to obtain the highest level of biomass and cellulose enzyme activity reaching a value of 9.828 log CFU/g and 0.0144 g/L.min, respectively. The potentiality of Bacillus amyloliquefacians D1B3 as a probiotic was examined in vitro. It also showed antimicrobial activity against Pseudomonas aeruginosa 9027, Klebsiella pneumoniae, and Escherichia coli 10536. The isolate tolerates low pH and bile salt (0.3% Oxygall). The hydrophobicity and coaggregation abilities were 1.7% and 69.79%, respectively. The results indicated that Bacillus amyloliquefacians D1B3 could be a potential probiotic additive for improving in vitro fermentation of wheat bran and suggests the possibility of combining the probiotic attributes of this strain with its cellulolytic ability to enhance the rumen fermentation of animal feed.

Low-moisture cereal products, such as traditional Tunisian coarsely milled barley, represent a vital global and regional dietary staple. However, their post-harvest processing is challenged by contamination with highly resilient endogenous spore-forming bacteria. This study investigated a sequential mild-thermal and UV-C hurdle technology, combining oven temperature (Factor A; 60, 80 and 100 °C) thermal treatment time (Factor B; 2, 6 and 10 min) with UV-C radiation (Factor C; 214.8, 644.4 and 1074.0 mJ/cm²), using a three-factor, three-level Box–Behnken experimental design coupled with response surface methodology (RSM). Three responses were evaluated: microbial logarithmic reduction (Y1), water activity a_w (Y2), and total color difference ΔE (Y3). Statistical analysis confirmed that thermal factors (A: oven temperature and B: thermal treatment time) served as the primary drivers of microbial inactivation, while UV-C light acted primarily at the immediate solid surface, inducing localized photothermal micro-evaporation that significantly affected surface water activity without degrading bulk chromatic properties. Multi-response optimization established an optimal processing window at an oven temperature of 94.5 °C, a thermal treatment time of 8.30 min and, a UV-C dose of 1074 mJ/cm². Experimental validation under these optimal conditions yielded a highly reliable 1.385 ± 0.013 Log CFU/g reduction in naturally occurring, heat-resistant spore-forming bacteria. Concurrently, the product maintained an exceptionally dry state (a_w = 0.34 ± 0) and preserved its natural visual attributes (ΔE= 2.77 ± 0.08). The low validation relative standard errors (RSE < 10% for physical attributes; 15.6% for microbial reduction) demonstrated a good predictive precision and industrial feasibility of the quadratic models.