TITLE:
Characterization of Amylase from Some Aspergillus and Bacillus Species Associated with Cassava Waste Peels
AUTHORS:
Ayantade Dayo Victor Ayansina, Ademola Olasoji Adelaja, Sani Sambo Datsugwai Mohammed
KEYWORDS:
Amylase, Bacillus, Aspegillus, Enzyme Activity
JOURNAL NAME:
Advances in Microbiology,
Vol.7 No.4,
April
26,
2017
ABSTRACT: Cassava
peels are generated as waste on soils during cassava processing in many
tropical countries. This work set out to isolate some microorganisms associated
with cassava peel degradation and characterize amylase enzymes responsible for
the degradation under some physiological conditions. A total of 30 bacteria was
isolated from the peels with Bacillus species occurring the most
(46.5%) and Enterobacter species (13.3%) being the next. Frequencies of
fungal isolations was Rhizopus sp. (35%); Aspergillus niger (25%); Aspegillus flavus (20%) and Penicillium species (20%). Bacillus cereus, Bacillus substilis Bacillus pumillus, Aspergillus niger and Apergillus flavus were selected and screened for their abilities to produce amylase.
Amylase activity was highest at day 4 for B. substilis (39.4 units/ml)
and A. flavus (66.1 units/ml); at day 3 for B. cereus (55.6 units/ml) and A. niger (44.6 units/ ml).
While maximum amylase activity was obtained at day 6 for B. pumilus (80.2 units/ml). Optimum pH for amylases from the two fungal isolate was
6.0 (A. niger = 53.5
units/ml and A. flavus = 65.4 units/ml). While optimum pH for B.cereus (51.7
units/ ml) and B. pumilus (44.6 units/ml) was 6.5 and for B. substilis (56.1
units/ml) at pH 7.0. Amylase activities increased from 20°C to 40°C for amylase from Bacillus sp. and 20°C to 50°C for amylase from the Aspergillus sp. after which there was a decline in activities as temperature
increased to 80°C.
Effect of heating duration (at 70°C for 5 minutes) on the amylase showed that A. niger has the highest activity of 127 units/ml. Effect of substrate
concentration on amylase activity showed that amylase form A. flavus had the highest activity of 72.2 units/ml at 0.4% substrate
concentration. The implications of the findings were discussed.