Bioprocess Engineering

Large Scale Production of Recombinant SXP1 Protein

The production of recombinant proteins involves several steps, which include genetic manipulation of the host organism, optimization of parameters for high yield, high level expression and down stream processing of the desired product. The work is in progress is mainly on the optimization of process parameters, designing the media, design of feed flow patterns for various mode of reactors, mathematical modeling and simulation of the recombinant protein production based on mechanism of induction involved. Problems related to rejection or non-expression of respective gene is also being looked at. Different strains of E.coli as host organism with required recombinant vector inserted is being tried to have the cost-effective large-scale production of the SXP-1 protein. Efforts are on in the direction of the large-scale isolation and purification of the intracellular SXP-1 protein by various means. SXP-1 is a recombinant clone isolated from w.Sancrofti L3CDNA library using B.malayi SXP-1 gene.

Extractive Fermentation of Lipase Using Aqueous Two-Phase System

In the extractive fermentation mode the product is removed out from the fermentation medium as soon as it is formed. One of the techniques that are frequently used is the membrane technique, which suffers from the problem of high cost, membrane fouling and difficulty in scaling up. Another way to avoid the above problems is cell immobilization in a solid matrix. The disadvantage of which mostly encountered in the reduction of transportation rate of nutrients to cellular cite and thereby the reduction in the conversion rate of substrate to product.

In this context, aqueous two-phase extractive fermentation found to be most effective. Aqueous two-phase has already been established as an excellent tool in the field of biomolecules separation and purification, especially for proteins. We are trying to utilize this wonderful system for purification and extractive fermentation of lipase enzyme from Candida rugosa. Aqueous two-phase systems offer different physical and chemical environments which allow for the partitioning of solutes such as proteins, cells, cell particles and nucleic acids. The differences in the phases are small, and therefore preclude the harsh treatment offered by traditional extraction systems.

In the global market seafood such as shrimps play a crucial role to meet the demand for protein food. The major constraint that has affected the shrimp culture industry is the occurrence of infectious and non-infectious diseases. Viral and bacterial infections of the shrimps have caused the most of the production loss in different parts of the world.

For example, the phases of PEG/dextran/water systems contain between 80% and 99% water by weight, possesses extremely low interfacial tensions (on the order of 10-7, and have been shown to provide a protective environment for biological materials. This compares rather favorably with organic solvent/water systems, such as butanol/water and ethanol/aqueous salt solutions. Such systems have high interfacial tensions (on the order of 10-4 organic phases containing only 40% to 50% water. These conditions lead to several problems, including precipitation and denaturation of proteins, and concentration of biological materials exclusively in the aqueous phase. The deleterious effects can be avoided through the use of aqueous polymer two-phase systems.