Optimization of protease production in indigenous Bacillus species isolated from soil samples in Lagos, Nigeria using response surface methodology
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Date
2019-02-06
Authors
Suberu, Yewande
Akande, Idowu
Samuel, Titilola
Lawal, Adekunle
Olaniran, Ademola
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier
Abstract
Proteases catalyse the hydrolysis of peptide bonds in proteins and offer a huge potential for application in
industries, including detergent, dairy, leather, baking, pharmaceutical and beverage industries. In this study,
indigenous Bacillus species were isolated from soil samples collected from abattoir, refuse and non-refuse sites in
Lagos, Nigeria and optimized for protease production. The isolates were purified on Bacillus agar and screened
for protease production on casein agar. Three strains showing high potential for protease production were
identified as Bacillus cereus ABBA1, Bacillus subtilis RD7 and Bacillus subtilis NRD9 via amplification and analysis
of 16S rRNA genes. Protease optimization was done Insilco using Box-Behnken Design (BBD) by response surface
methodology (RSM) with Design-Expert software and then validated experimentally. Factors optimized include
temperature, pH, carbon and nitrogen source and inoculum density. Statistical analysis was done using ANOVA.
The results obtained from the Insilco experimental model revealed high protease activity of 159.43 U/ml, 141.28
U/ml and 138.17 U/ml while experimental validation generated a high protease activity of 200.56 U/ml, 176.00
U/ml and 163.76 U/ml for strains ABBA1, RD7 and NRD9, respectively in optimized medium. This corresponds
to 33.54-, 42.21- and 36.64- fold increase in protease production compared to the unoptimized protease production
medium. The optimum conditions for extracellular protease production obtained from quadratic model
of RSM were 40 °C, pH 8.5, 2.5% (v/v) inoculum density, 1.5 g/L maltose and 2.0 g/L beef extract powder. The
model prediction agreed with the experimental data (R2=0.98) and was statistically significant (p≤0.05). This
results further confirms the need to optimize the production parameters to achieve maximum yield and economical
use of available resources during production of industrially important enzymes.
Description
Keywords
Research Subject Categories::NATURAL SCIENCES::Chemistry::Biochemistry , Bacillus isolates , Box-Behnken design , Protease activity , Protease optimization
Citation
Yewande Suberu, Idowu Akande, Titilola Samuel, Adekunle Lawal, Ademola Olaniran. Biocatalysis and Agricultural Biotechnology 18 (2019) 101011.