Statistical optimization of acid phosphatase production by Trichoderma spp. in submerged fermentation

The production of acid phosphatase (ACPase) by Trichoderma spp. was evaluated and optimized under submerged fermentation using low-cost culture media. Among the strains tested, T. reesei showed the highest enzymatic potential. A Central Composite Design was applied to assess the effects of sucrose, yeast extract, and KH₂PO₄ on ACPase activity. The optimized medium (MSO-Tr) resulted in a maximum enzymatic activity of 1.96 ± 0.14 U/mL and biomass production of 5.32 ± 0.48 g/L, representing a 3.3-fold increase compared to preliminary conditions. T. harzianum and T. asperellum showed lower activities, reaching 0.81 ± 0.05 U/mL and 0.76 ± 0.12 U/mL, respectively. Substrate consumption analysis indicated complete utilization of sucrose and glucose within 48 h for T. reesei. Response surface analysis demonstrated that yeast extract positively influenced enzyme production, whereas excess phosphate had inhibitory effects depending on the strain. SDS-PAGE analysis revealed protein bands in the 58-69 kDa range, consistent with the reported molecular weights of fungal acid phosphatases. These results demonstrate the effectiveness of statistical optimization and highlight the biotechnological potential of Trichoderma-derived ACPases produced using low-cost substrates.