Byproducts from cassava industry: alternative substrates for cyclodextrin glycosyltransferase production by alkalophilic Bacillus trypoxylicola SM-02

Abstract

In the present work was studied the use of cassava peel flour (CPF), corn steep liquor (CSL), and cassava wastewater as substrates to produce cyclodextrin glycosyltransferase (CGTase) from a new alkalophilic isolate of Bacillus trypoxylicola SM-02 by submerged fermentation. The experiments were performed as a Central Composite Design 22 , totalizing 11 assays. An enzymatic activity of 352.53 U/mL was obtained using 1.5 g of CPF and 0.6 g of CSL. The optimum temperature and pH of CGTase was 55 °C and 8.0, respectively. The CGTase depicted a relative activity of more than 50% for 120 min at the optimum temperature. The only salt that positively influenced the CGTase activity was CaCl2. The results are indicative of a potential role of B. trypoxylicola SM-02 in the production of CGTase using residual substrates.

Resumen: En el presente trabajo estudiamos el uso licor de maíz fermentado (LMF), harina de cáscara de yuca (HCY) y aguas residuales de yuca para la producción de ciclodextina glicosiltransferasa (CGTase) por un nuevo aislado alcalófilo de Bacillus trypoxylicola SM-02 en fermentación sumergida. Los experimentos se realizaron por Diseño Central Compuesto Rotativo 22 totalizando 11 ensayos. La mayor actividad enzimática de 352.53 U/mL se obtuvo con 1.5 g de HCY y 0.6 g de LMF. La temperatura y el pH óptimos fueron 55 ºC y pH 8.0, respectivamente. CGTase mostró una actividad relativa superior al 50% durante 120 min. a la temperatura óptima. Solo el CaCl2 mostró actividad positiva para CGTasa. Los resultados apuntaron a un buen potencial de B. trypoxylicola SM-02 para la producción de CGTasa usando substratos residuales.