OPTIMIZATION OF TOTAL SOLUBLE PROTEIN PRODUCTION BY Trametes sp. isolate B7 AND ENZYMATIC DEGRADATION OF SYNTHETIC DYES

Abstract

Filamentous fungi as a source of bioproteins for biotechnological applications are preferred over bacteria and yeasts due to their excellent yield and total volume of production. Fungal laccases are useful because of high redox potentials and low substrate specificity to xenobiotics. However, challenges for large-scale utilizations are low enzyme yield and high cost of production. Saw-dust of Terminalia superba abounds locally and was utilized as alternative substrate for production using various optimization processes. Trametes sp. isolate B7 was isolated and identified using molecular techniques. Optimum pH and temperature for total soluble protein (TSP) and laccase activity were pH 5.0 (3.6 mg/mL, 2356 U/mL) and 25oC (2.3 mg/mL, 2395 U/mL), respectively. Enhanced production of TSA occurred in Cu2+ (2.70 mg/L) and Ca2+ (2.50 mg/L) at 3 mM. Laccase activity was recorded at 1 - 2 mM Cu2+ (2379 U/mL) and 3 - 4 mM Ca2+ (2385 U/mL). Productions of TSP and laccase activity were higher using ammonium sulphate and ammonium chloride respectively. Glucose induced the best TSP and laccase activity of 3.6 mg/mL and 2395 U/mL respectively. TSP and laccase activity were best on day 14 (3.6 mg/mL) and day 18 (2395 U/mL) respectively. Percentage degradation of synthetic dyes using crude laccase 1000 U/mL (and 2000 U/mL) were: Remazol Brilliant Blue Royal 100% (77%), Phenol red 28% (36%), Congo red 75% (64%), and Malachite green 62% (28%) respectively. The ability of laccase to degrade Phenol red and other synthetic dyes without using enzyme mediators made it a valuable tool for biotechnological applications.