African Journal of Agrophysics

African Journal of Agrophysics ISSN: 7201-3621 Vol. 2 (1), pp. 056-064, January, 2018. © International Scholars Journals

Full Length Research Paper

Effects of mutanase fermentation conditions in shaken flasks

*Robert C. Armstrong, John Oprah and walt Kennedy

Department of Industrial Microbiology, Maria Curie-Sk Å‚odowska University, Akademicka 19, 20-033 Lublin, Poland.

E-mail: dr.robertm@yahoo.com

Accepted 12 December, 2017

Abstract

The present paper describes optimization of fermentation conditions in shaken flasks and scale-up of fermentor production up to 115 L. The response surface methodology (RSM) has been successfully applied in standardization of mutanase production by Trichoderma harzianum CCM F-340. The model was very well fitted to the experimental data and explained more than 96% of the whole variation of the response (adjusted R2 = 0.962). In order to confirm the adequacy of the regression model based on the experimental data, validation cultures were grown in conditions created through optimization. The highest enzyme activity (0.747 U/mL) was reached in shaken flask cultures on Mandels medium in a volume of 140 mL modified in terms of carbon (cell wall preparation from the polypore fungus Laetiporus sulphureus 8.08 g/L) and nitrogen (soybean peptone 1.38 g/L) sources, under culture conditions 30°C, pH 5.3, agitation 270 rpm. The scale-up of the culture in the bioreactors with a working volume of 5 and 115 L resulted in a slight decrease in the mutanase activity (0.734 and 0.682 U/mL, respectively). The validation experiment showed a 70.6% increase in the production of mutanase compared with the culture before optimization. The results proved that the cultures could be scaled-up successfully from shaken flasks to the bioreactor scale. Our results indicate that in optimal conditions, T. harzianum could be a highly effective extracellular mutanase source. This report is the first to deal with optimization of mutanase biosynthesis using a mathematical model and scale-up of enzyme production in controlled fermentors with a view to facilitate application thereof in industry.

Key words: Mutanase, Trichoderma harzianum, response surface methodology (RSM), bioreactors, submerged culture.