Comparative pretreatment method for efficient enzymatic hydrolysis of Salvinia cucullata and sewage treatment in ponds containing this biomass

Effect of various chemical pretreatments (HCl, H₂SO₄, NaOH, H₂O₂ and NaOH/H₂O₂) and ultrasonication pretreatment for delignification to enhance enzymatic hydrolysis was evaluated for Salvinia cucullata. After pretreatment, saccharification was carried out using crude cellulase enzymes produced from Trichoderma reesei Rut C30. The alkaline/oxidative pretreatment gave maximum reducing sugar yield of 341.8 mg/g of dry biomass. When this S. cucullata was used in the pond for sewage treatment, the chemical oxygen demand, total Kjeldahl nitrogen and PO₄ removal rates were found to be 84.7 ± 3, 84.4 ± 1 and 94.0 ± 1 %, respectively, making it possible to grow this plant in oxidation pond while simultaneously offering adequate treatment to the sewage. The biomass yield of 39 ± 2 t/ha·year was observed in this experiment, with potential to produce reducing sugar in the range of 12.6–14.0 t/ha·year for biofuels production. Thus, harvested biomass from aquatic pond can be used for biofuel without having conflict with agricultural land.