RESUMO
@#Aims: In recent years, microbial conversion of renewable raw materials has become an important objective in industrialbiotechnology. Wastes from Opuntia ficus indica (OFI) can be considered as potential renewable raw materials in lacticacid production. In this study, the feasibility of lactic acid production using fruits and cladodes of OFI as carbohydratefeedstock was investigated.Methodology and results: Response surface methodology (RSM) based on central composite design (CCD) was usedto evaluate the effects of fermentation parameters for lactic acid production from OFI fruits by Lactococcus lactis subsp.lactis strain, isolated from Algerian raw camel milk. Acid hydrolysis of the OFI cladodes biomass was performed by diluteH2SO4 pretreatment. Lactic acid production from OFI fruits was analyzed using response surface methodology.Variables such as inoculum age and reducing sugars concentration were found to significantly influence lactic acidproduction. Final lactic acid concentration and productivity attained under optimum fermentation conditions were 32.5g/L and 0.74 g/L.h, respectively. The cladodes of OFI are a potential biomass feedstock for lactic acid production. Themaximum lactic acid and volumetric productivity were 16.85 g/L and 0.65 g/L.h, respectively.Conclusion, significance and impact of study: Wastes from OFI can be a good feedstock for lactic acid production byLactococcus lactis subsp. lactis. The methodology as a whole proved to be quite adequate for the design andoptimization of the process. The experimental results also demonstrated the feasibility of using OFI cladodeshydrolysate as a substrate for lactic acid production.