title: Impact of aeration and agitation on metabolic heat and protease secretion of Aspergillus tamarii in a real-time biological reaction calorimeter.
abstract: The effects of aeration and agitation on metabolic heat, alkaline protease production and morphology for Aspergillus tamarii MTCC5152 are reported in this manuscript. Measurement of metabolic heat has been attempted by the continuous and dynamic heat balance method in a biological real-time reaction calorimeter. At lower agitation intensities, growth-related processes were dominating. As a result the protease activity and the product heat yields were lower than those for 350 and 450 rpm. Although biomass growth was necessary to obtain maximum protease yield, agitation seemed to play a vital role in the protease production process. Energy dissipation per circulation function of the process is also deduced from power input. At optimal conditions, 350 rpm and 1 vvm, the gassed power required was 0.133 W. Pellet morphology and protease production were studied under different aeration and agitation intensities of A. tamarii. Pellet structure was considerably influenced by DO, a higher DO level resulted in denser pellets (1,018.4 kg/m(3)) leading to higher protease activity. Coupling of hydrodynamics and bio-reaction highlighted the complex relationship between energy dissipation, substrate uptake rate and fungal physiology. This study emphasised the potential of biocalorimetry as a reliable monitoring and robust control tool for aerobic fermentation of A. tamarii, using agricultural by-products.
authors.affiliation: Chemical Engineering Department, Central Leather Research Institute, Adyar, Chennai 600 020, India.
authors.forename: Balaji
authors.initials: B
authors.lastname: Dhandapani
authors.forename: Surianarayanan
authors.initials: S
authors.lastname: Mahadevan
authors.forename: Sathish Sundar
authors.initials: SS
authors.lastname: Dhilipkumar
authors.forename: Suseela
authors.initials: S
authors.lastname: Rajkumar
authors.forename: Asit Baran
authors.initials: AB
authors.lastname: Mandal
mesh_terms: D001230:Aspergillus / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000008:administration & dosage* / Q000235:genetics; D061249:Batch Cell Culture Techniques / Q000295:instrumentation* / Q000379:methods; D019149:Bioreactors / Q000382:microbiology; D002151:Calorimetry / Q000379:methods*; D010450:Endopeptidases / Q000008:administration & dosage* / Q000235:genetics; D005110:Extracellular Space / Q000737:chemistry / Q000201:enzymology*; D005285:Fermentation; D006358:Hot Temperature; D021381:Protein Transport
chemical_list: D001426:Bacterial Proteins; D010450:Endopeptidases; C087822:alkaline protease