Résumé
The enzyme α-L-rhamnosidase specifically cleaves terminal rhamnose residues from a wide variety of natural products. This property endows this enzyme with important biotechnological potential as L-rhamnosidase could be employed in a variety of applications, including removing bitterness from citrus fruit juices, improving the aroma of wines and converting clinically important steroids. This work optimized α-L-rhamnosidase solid-state fermentation production from Aspergillus niger 426 using statistical methods. Firstly, a statistical mixture-design with three components to determine the best ratio of nutrients for enzyme production was carried out. The optimal conditions consisted of growing the fungi in media containing 0.14 g of cane sugar bagasse, 1.25 g of soybean hulls and 3.05 g of rice straw; these conditions achieved a maximum α-L-rhamnosidase activity of 1.92 U / mL. Next, a 3² Box-Behnken design to optimize culture moisture levels and nutrient solution pH values for enzyme production was carried out. α-L-rhamnosidase activity increased to 3.02 U / mL when medium moisture was 75.5% and pH value of 4.0.