Lactic acid bacterial strains isolated from Attiéké (semolina cassava): bio-tools for combating emergent pathogens in the context of climate change

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Background Global climate change, particularly the rise in ambient temperatures, may promote the emergence and proliferation of pathogenic bacteria, thereby increasing food safety risks. Identifying robust bioprotective microorganisms that can retain their antimicrobial activity under elevated temperatures is therefore essential. Objective This study investigated the biopreservation potential of lactic acid bacteria (LAB) isolated from Attiéké (cassava semolina) fermentation, focusing on their functional properties and antibacterial activity across a range of temperatures relevant to climate change scenarios. Methods LAB isolates were evaluated for enzyme production, hemolytic activity, and the antibacterial activity of cell-free supernatants obtained after cultivation at 25 °C, 40 °C, 42 °C, 45 °C, and 50 °C. Additionally, their antibiotic susceptibility, lactic acid production, and hydrogen peroxide production were assessed. Selected strains were identified using polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP) followed by 16S rDNA sequencing. Results Six LAB strains were identified, belonging to two species: Lactobacillus plantarum (LB 91, LB 92, LB 94, and LB 100) and Enterococcus faecalis (LB 95 and LB 152). All isolates were Gram-positive and exhibited γ-hemolysis. Strains LB 91, LB 92, LB 95, and LB 100 showed amylase and cellulase activities. The supernatant of strain LB 95 was the only one capable of inhibiting all tested pathogenic bacteria at all cultivation temperatures. All strains were sensitive to amikacin, minocycline, penicillin, erythromycin, and streptomycin. The highest lactic acid concentration (2.425 ± 0%) was recorded in LB 95 at 40 °C, while the highest hydrogen peroxide production (0.168 ± 0 mL) was observed in LB 94 at 25 °C. Conclusion LB strains isolated from Attiéké demonstrated promising biopreservation properties at elevated temperatures. Among these strains, Enterococcus faecalis LB 95 exhibited the strongest antimicrobial activity and safety-associated traits, highlighting its potential as a bioprotective culture in a warming climate.

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