β Scribed by Professor Virendra Bisaria; Professor Mamata Mukhopadhyay
No coin nor oath required. For personal study only.
Over the past two decades the Indian economy has seen a sustained high growth rate. Currently at over 8%, this growth makes India a significant contributor to the global economy. The chemical industry is one of the fastest growing sectors that accounts for a sizeable proportion of the country's gross national product. Similarly the biotechnology industry, especially pharmaceuticals, is also growing at a fast pace with the adoption of progressive policies of the government. Efforts are being made to gradually shift from the conventional labour-intensive industry and export of raw materials to technology-intensive industry through value addition of the existing processes. The traditional resource based products derived from petroleum, coal etc. are being gradually replaced by less energy-intensive and more eco-friendly technologies based on green chemistry and biotechnology. Various Departments and Ministries of the Government of India such as the Department of Science and Technology, the Department of Biotechnology, the Ministry of Chemicals and Fertilizers and the Ministry of New and Renewable Energy are providing support which is spearheading this transition. They are formulating progressive policies conducive to research and development as well as facilitating the translation of R&D data into commercial enterprises. The promotion of international collaboration between scientists and engineers of India with their counterparts in other countries by various schemes of Indian Government is also playing an important role in promoting not only academic communications for mutual benefit but also for global economic development of Indian industry.
This Indian Special Issue of the Journal of Chemical Technology and Biotechnology, which contains one review and eleven research papers, including a technical note, provides a snapshot of the current research activities being pursued in various areas of chemical technology and biotechnology at some of the leading institutes and universities in India. The review on application of cavitational reactors for cell disruption for recovery of intracellular enzymes by Gogate and Pandit provides a summary of up-to-date status of the work carried out in this area. The cost of recovery of intracellular enzymes and metabolites constitutes a significant component of the overall economy of the process. Such types of reactors are therefore significant as they have the potential to reduce the energy requirement for isolation of intracellular compounds by an order of magnitude compared to the conventional cell disruption techniques on an industrial scale. The research paper on CO 2 absorption into amine solution by Suresh and Srinivas outlines a novel strategy for intensification based on addition of ferrofluids due to enhancement in mass transfer coefficient in gas liquid systems. Aerogel is the lightest and lowest-density solid material ever known to exist, which is produced by replacing primary solvent ethanol from the gel without a vapor-liquid interface to avoid collapse of the pores by capillary forces. Supercritical drying of aerogels using carbon dioxide above its mixture critical pressure is a recent technique for producing crack-free aerogels. Mukhopadhyay and Rao attempt, for the first time, to elucidate the requirement of process conditions by proposing the mechanism of the process and focusing on mass transfer modeling for silica aerogel of known configuration.
The biotechnological processes employ different types of microbial mutants for production of fine chemicals and therapeutic compounds. Srivastava and Wangikar have described the combined effects of carbon, nitrogen and phosphorus substrates on the production of D-ribose, an important intermediate in the pharmaceutical industry, via a transketolase deficient strain of Bacillus pumilus. They showed that D-ribose was overproduced by manipulation of these substrates using a mutant strain of Bacillus pumilus with impairment in the non-oxidative part of the pentose phosphate pathway. The T7 based expression system is widely used for producing recombinant proteins in Escherichia coli as expression levels of proteins reach up to 50% of total cellular protein, which facilitate downstream processing. However, for efficient large scale production, the system should be stable. In a research paper on stability studies with different vector backbones utilizing the T7 expression system in Escherichia coli, Walia et al have shown that the pCR2 vector backbone is a useful addition to the repertoire of E. coli for scaling up high level expression system in the absence of selection pressure. High level expression of recombinant proteins in E. coli leads to intracellular accumulation of partially folded protein intermediates in the form of inclusion bodies. Their recovery and renaturation into active form is one of the major downstream processing steps for efficient purification from the intracellular fluid. In a research paper Singh et al have shown a simple alternative of solubilisation of inclusion body proteins by using alkaline pH instead of commonly used methods which employ high molar concentration of chaotropic solvents for their efficient recovery.
Because of increasing awareness, the use of toxic solvents is restricted in processes where the products are intended for food applications. Towards the development of green technologies, supercritical fluids offers the possibility to replace conventional toxic organic solvents. Their application has been successfully demonstrated by Varma and Madras for synthesis of butyl butyrate in supercritical carbon dioxide in the presence of lipase enzyme. Beta-lactam antibiotics, penicillins and cephalosporins, continue to remain the most widely used antibiotics for treating bacterial infections. In a research paper on insight into microwave irradiation and enzyme catalysis in
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