Biomedical subjects

Satish J Parulekar

Publications and source records attributed to Satish J Parulekar.

3 recordsLinked to original sources

PubMed2002

Effect of environment partitioning on the survival and coexistence of autocatalytic replicators.

The paradigm of cubic autocatalytic replicators with decay in coupled isothermal continuous stirred tank reactors is selected as a model to study complex behavior in population dynamics of sexually reproducing species in a heterogenous environment. It is shown that, even a setup with single species in two coupled environments may have regions in parameter space that result in chaotic behavior, hence segregation in the environment causes complexity in the system dynamics. Furthermore, partitioning is found to lead to emergence phenomena exemplified by steady states not obtainable in the equivalent homogeneous system. These phenomena are illustrated through case studies involving single or multiple species. Results show that the coupled environments can host species, that would not survive should the coupling be removed.

Animals↗

PubMed2002

A morphologically structured model for penicillin production.

A morphologically structured model is proposed to describe penicillin production in fed-batch cultivations. The model accounts for the effects of dissolved oxygen on cell growth and penicillin production and variations in volume fractions of abiotic and biotic phases due to biomass formation. Penicillin production is considered to occur in the subapical hyphal cell compartment and to be affected by availability of glucose and oxygen. As it stands, the model provides a wide range of applicability in terms of operating conditions. The model has been tested for various conditions and has given satisfactory results. A series of glucose feeding profiles have been considered to demonstrate the capabilities of the proposed model. It is concluded that the model may be valuable for the interpretation of experimental data collected specifically for metabolic flux analysis during fed-batch cultivation because the elements of measured specific production rates are determined from measurements of the concentrations of the components and their mass balances. The proposed model may be further used for developing control strategies and model order reduction algorithms.

Bioreactors↗

PubMedDate not supplied

A dual-growth kinetic model for biological wastewater reactors.

Biological wastewater reactors are traditionally divided into two groups based on modes of cell growth: suspension and attached (biofilm) growth. Kinetic descriptions of these reactors are based on confining cell growth to solid surfaces or void space. Because suspended cells grow in void space and biofilms grow on surfaces, both forms of microbial growth must in principle occur in a biological reactor, unless the surface is inhabitable by a biofilm. Cell growth and substrate utilization in both modes, suspension and attached, are fully accounted for in the model developed here. Simulations based on this model show that biofilms growing on the walls of a reactor, classified as a suspension culture, can contribute substantially to the total organics removal. Similarly, suspended cells in the voids of a "traditional biofilm" reactor can contribute significantly to degradation of organic substrates. The presence of biofilms can obviate total washout of suspended cells and avert reactor failure. Model simulations enable a comparison of attached and suspended biomass in terms of biomass accumulation, substrate degradation, and effectiveness of substrate utilization and illustrate interactions between the two forms of biomass. The model provides a unified way to analyze and design biological wastewater processes.

Biofilms↗