| Abstract: |
In this study, extracellular enzyme production by different species of Trichoderma fungus (T. aureoviride NAS106, T. afroharzianum NAS107, T. ghanense NAS108, T. pleuroticola NAS109, T. harzianum NAS110, and T. lixii NAS114) were investigated under submerged fermentation conditions using lemon peel waste as a substrate at 28 °C, pH 5, and fermentation time of 48 h. Extracellular protein concentration, cellulose (exoglucanase, endoglucanase, β-glucosidase, and total cellulase), xylanase, and pectinase enzyme activity were also assayed. This study also examined the effect of different fermentation times on extracellular protein production and enzymatic activity in a superior strain of Trichoderma. The molecular weight of extracellular proteins was studied using SDS-PAGE. The results showed that the highest extracellular protein concentration and exoglucanase, endoglucanase, beta-glucosidase, total cellulase, xylanase, and pectinase activity were produced in T. afroharzianum NAS107. It was also revealed that the major activity of the total cellulase enzyme was due to the synergistic function of endoglucanases and cellulohydrolases. In addition, the electrophoretic pattern of protein bands of this species showed the ability to produce enzymes of xylanase (Xyl I), exoglucanase (Cel 6A (CBH II) and Cel7A (CBH I)), endoglucanases (Cel 5A (EG II), and Cel 12A (EG III), β-glucosidase (Cel3A (BGL I) and Cel 1A (BGL II)), polygalacturonase I and II, pectin lyase, and pectin esterase I and II, with the highest enzymatic activity during the fermentation period of 96 to 120 h due to the synergistic activity of exoglucanase, endoglucanase, beta-glucosidase, and xylanase enzymes. The findings of this study showed that T. afroharzianum is a suitable producer of extracellular enzymes cellulase, xylanase, and pectinase. Thus, it can be used as a biological substance or an enzyme source for saccharification of citrus conversion industry wastes such as lemon peel. [ABSTRACT FROM AUTHOR] |
