Determination of mycelium-bound lipase b-N-acetyl-D-glucosaminidase activity from Aspergillus niger MYA 135 in submerged process

COLÌN V. ROMERO C, BAIGORÍ M, PERA L

Tafi del Valle. Tucuman

Jornada; XXII Jornadas Cientificas Asociación de Biología de Tucumán Tafi del Valle Tucumán; 2005

Sociedad de Biologìa de Tucuman

DETERMINATION OF MYCELIUM-BOUND b-N-ACETYLD- GLUCOSAMINIDASE ACTIVITY FROM ASPERGILLUS niger MYA 135 IN SUBMERGED PROCESS Col.n V, Romero C, Baigor. M, Pera L. PROIMI Av. Belgrano y Pje. Caseros, 4000 Tucum.n. Tel: 4344888, E-mail: lpera@hotmail.com Introduction. Filamentous fungi grow by apical extension, localized apical synthesis that creates a tubular hyphal morphology. Besides linear tip extension, filamentous fungi branch to form new intercalary growing tips. Wall lytic enzymes have an important role in the process of apical growth. However, the events involved are still not clearly understood. One of the wall lytic enzymes is the activity b-N-acetyl-D-glucosaminidase (NAGase), that we use as a relative marker of the wall lytic potential. Objective. Evaluation of NAGase activity during fungal development in submerged process. Materials and methods. Aspergillus niger (ATCC MYA 135) was grown at 30°C in MB (g/l): sucrose 10; NH4NO3 2; KH2PO4 1; MgSO4.7H2O 0.2; CuSO4.5H2O 0.06; pH5. NAGase activity was determined using 0.01 g of wet mycelium and p-nitrophenyl-Nacetyl- b-D-glucosaminide as substrate. Results and conclusions. Both NAGase specific activity and branch frequency increase during fungal growth. The maximum NAGase specific activity was 0.550U per mg of dry weight.