Abstract:
The a-amylase and glucoamylase activity of three fungi (Aspergillus niger, Trichoderma viride
and Rhizopus oryzae) in mono and mixed culture was determined under submerged fermentation
(SmF) process. Rice mill feed (RMF); an agro-industrial by-product of rice milling was used as
substrate.
Fifty (50) ml of a basal medium containing 0.5gm of RMF in 150ml Erlenmeyer flasks were
prepared in triplicates for each fungus and their mixed culture. Sterilization was carried out by
autoclaving at 121'C for 15 mins and 15psi. The flask was allowed to cool before inoculating
with 3ml of inoculums and incubated for 7 days at 30'C+_2'C. The flasks were placed on a rotary
shaker (80rpm) for one hour daily during incubation. At the end of the incubation period, the
contents of each flask were filtered through Whatman number 1 filter paper and taken as crude
enzyme extract for ? amylase and glucoamylase activity determination.
The a- amylase activity recorded in single culture SmF of RMF was significantly higher (p<0.05)
in Aspergillus niger (20.67 Iu/ml) compared to T. viride (13.00 Iu/ml) and R. oryzae (12.00
Iu/ml). Glucoamylase activity recorded wit A. niger under SmF was numerically (20.33Iu/ml)
higher than values recorded with T. viride (15.57Iu/ml) and R. oryzae (18.57Iu/ml).
Glucoamylase and a-amylase activity was significantly (p<0.05) higher in mixed culture of all 3-
fungus compared to the other mixed culture treatments. Significantly higher (p<0.05)
glucoamylase activity (48.00 Iu/ml) was expressed when all three fungi were present followed by
the mixed culture of A. niger + R. oryzae (33.00Iu/ml). |
