Herein, we explore the probiotic potentials and soybean meal (SBM) compound feed fermentative applications of Lactobacillus plantarum SK1305 strain isolated previously from Korean green chili pickled pepper (gochu-jangajji). The isolate exhibited higher acid (pH 2.5) and bile tolerance (0.3%, w/v) up to 2 h and 4 h, respectively. The cell-free culture supernatant (CFCS) displayed a broad spectrum antibacterial activities against various pathogens, which may be ascribed to high lactic acid production (L-form, 86.8 ± 0.8 mM and D-form, 44.8 ± 0.2 mM). Further, the strain displayed high cell-surface hydrophobicity (92.7 ± 1.0%), coupled with low auto-aggregation (23.6 ± 4.4%) but relatively higher co-aggregation properties with C. perfringens (49.6 ± 0.6%) as well as H2O2 (1.0 mM) resistant property. Additionally, the isolate displayed significant DPPH free radical scavenging activity (55.2 ± 0.6%) and superoxide reducing ability in MAC-T cells. Considering safety, the isolate has no transmissible antibiotic resistant genes and harmful enzymes as well as non-hemolytic activities. Ushered by these appreciable probiotic properties, the isolate was used for solid state fermentation (SSF) of SBM compound feed. Notably, we observed a higher strain adaptability (> 1010 CFU/g) following the production of L- (> 6.0 ± 0.0 mM) and D-form (> 5.2 ± 0.3 mM) lactic acid during fermentation for 8 h. The methanolic extracts of fermented feed displayed high antibacterial and antioxidant activities, affirming the potential functional activities of fermented compound feeds. Therefore, L. plantarum SK1305 may act as a worthy inoculum toward fermentation of feed with enhanced nutritional properties.
Keywords: Antibacterial activity; Antioxidant activity; Lactic acid; Lactobacillus plantarum SK1305; Solid state fermentation.