Microbial Remediation of Cyanogenic Glycosides and Valorisation of Cassava Mash Using Lactococcus lactis (PX273919) during Garri Production

Abstract

Garri is a fermented cassava product in which cyanogenic glycosides may remain a food-safety concern when processing is inadequate. This study evaluated cyanide remediation and cassava-mash valorisation during garri production using Lactococcus lactis (PX273919). Bacterial isolates from fermented cassava mash were characterised by standard microbiological and molecular procedures, and L. lactis (PX273919) was selected for bioaugmentation. Cassava mash (250 g) was inoculated with 2.5 mL of culture at 2.0 × 10⁵ CFU/mL and assessed during fermentation. Cyanide was determined using the alkaline picrate method and infrared spectroscopy, while proximate composition was evaluated to assess nutritional changes. Initial cassava mash contained 0.085% cyanide, which decreased to 0.064% in unfermented garri. After 24 h, cyanide was 0.048% in L. lactis-treated garri compared with 0.063% in the untreated control. After 48 h, corresponding values were 0.052% and 0.062%, respectively. Infrared spectra showed nitrile absorption bands in cassava mash and garri samples, indicating residual cyanide after processing. Proximate composition varied with treatment and fermentation time; at 48 h, treated garri contained 2.19% protein, 1.5% fat and 86.86% carbohydrate. Energy values also differed between treated and untreated garri at 48 h. Overall, fermentation with L. lactis (PX273919) was associated with lower cyanide concentrations than untreated garri while supporting changes in proximate composition during garri production.