Journal of Pure and Applied MicrobiologyVol. 3 No. 2

Studies on Pelleted Form of Growth Morphology Achieved by Aspergillus strains with Different Sugar Treatment Under Submerged Cultivation

Nitin Verma*, M.C. Bansal and Vivek Kumar

Department of Paper Technology, Indian Institute of Technology, Roorkee Saharanpur Campus, Saharanpur - 247 001, India.

Received on 06 March 2009 and accepted on 12 April 2009

 

ABSTRACT

Filamentous fungal fermentation is widely used to commercially produce useful products such as organic acids, enzymes, antibiotics etc. Fungi can be grown in submerged cultures in several different morphological forms: suspended mycelia, clumps, or pellets. A change in fungal morphology is influenced by medium composition, inoculum, pH, medium shear, additives (polymers, surfactants, and chelators), culture temperature, and medium viscosity. Inoculum size is generally recognized as of great importance to the process of fungal pellet formation. Many industrially significant microbial products are produced during secondary metabolism by fungal pellets. Morphology of the fungal pellets has a significant influence on the mass transfer and turn over processes in submerged cultures. In pellets with a loose hyphal structure, convictive transport is possible, but does not necessarily result in higher conversion rates compared to compact pellets morphology. The interaction of hyphae is important in determining the possibility of pellets formation .The pellet diameter and compactness were affected by the agitation intensity of the broth. It has been concluded that fungal growth in pellet form is a favorable alternative which benefits most of the fungal fermentations due to better mass and oxygen transfer into the biomass and lower energy consumption for aeration and agitation. This paper describes the pellets morphology achieved by different fungal strains under culture (PDB) and the production media(with varying sugar components) at 30°C and 180 rpm.

Keywords : Pellets, Fungal strains, Growth morphology, Pellet diameter, Mass transfer.