The effects of Psidium guajava leaf extract on the production of cellulases and glucose oxidases by Aspergillus niger

Aspergillus niger, is a filamentous fungus and producer of industrial enzymes such as glucose oxidases and cellulases. These enzymes are naturally produced by the fungus in order to digest and absorb nutrients from its environment.  However, the enzyme quantities that are naturally produced are low.  Thus, the aim of this study was to determine the effects of Psidum guajava leaf extract on the production of cellulases and glucose oxidases from Aspergillus niger. The leaves of Psidium guajava were extracted using absolute methanol.  Aspergillus niger was then grown in the presence and absence of the extract in order to investigate the effects of extract on enzyme production by the fungus.  The enzymes secreted into the broth medium were isolated by centrifugation. The supernatant which contained the secreted enzymes was used for the determination of enzyme activity.  Enzyme activity was determined using the specific substrate for the specific enzyme, such as 2 % cellulose for cellulase and standard glucose solution for glucose oxidase.  The results showed that the Psidium guajava leaf extract had an effect on production and activity of cellulases and glucose oxidases.  From this study, it was noted that the Psidium guajava leaf extract may be used to induce the production of enzymes by Aspergillus niger and these enzymes may be of industrial use.