Abstract
Aim: To investigate increased thermal influence on morphology of Aspergillus carbonarius during RSDA production. Place and Duration of Study: Microbial fermentation Unit, Department of Microbiology, Faculty of Biological sciences, University of Nigeria, between July 2009 and August 2010. Methodology: In shake flask cultures thermal influence on A. carbonarius morphology and productivity investigated. Mycelial morphology was characterised by means of image analysis using as parameters, mean diameter, roughness, circularity and compactness of pellet. Thermal effect on amylase activity, total protein, biomass concentration and pH were also investigated. Results: Shifting the temperature from 27oC to 37oC significantly affected the morphological parameters of the pellets, but RSDA activity was not altered. The interesting thing about the morphology is the shearing off of the hairy part of the pellet at an increased temperature and subsequent agglomeration. At 27oC the RSDA activity increased steadily with an optimum activity of 293U/ml at 96h and subsequently decreased to 75U/ml by the end of the fermentation. At 37oC a maximum activity of 291U/ml was achieved at 72h of fermentation but this decreased to 87U/ml at the end of fermentation. Higher biomass concentration and total protein were obtained at 37oC. The pH dropped from an initial of Research Article British Microbiology Research Journal, 3(3): 355-367, 2013 356 5.0 to 3.0 and 2.5 for 27oC and 37oC temperature conditions respectively. Conclusion: Induced thermal increase resulted to changes in pellet morphology but raw starch digesting amylase activity was not altered.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call