Biosensors & Bioelectronics

Biography

Biography: Alok barua

Abstract

Of late, there has been a growing interest in biotechnology among the researchers. A multi-disciplinary approach is needed to meet the requirement of biotechnology industries. Bioprocesses such as production of fermented foods with the help of micro-organisms, has been known in ancient civilization. Bioprocesses have been developed for large number of commercial products like industrial alcohol, organic solvent, baker’s yeast, etc. and special products like antibiotics, therapeutic proteins and vaccines. Bioprocess operations make use of microbial, animal and plant cells and components of cells such as enzymes, to manufacture new products and to destroy harmful wastes. These processes require effective control techniques due to increased demand on productivity, product quality and environmental responsibility. It is typically so in the case where the biomaterials used in the process are costly and required stringent control over product formation as in animal cell culture. Bioreactor is where the bioprocess operation takes place and its design and controlled operation are very important for several aspects of production like purity, quantity, efficiency, safety, etc. Basically, there are two kinds of bioprocesses; one aerobic and the other anaerobic, depending on whether oxygen is required or not required to carry out the bioprocess operation. There are several types of bioreactors designed and used in the laboratory as well as in large scale industrial applications. Some of these are continuous stirred tank, bubble column, airlift, see-saw and packed bed reactors. As their names indicate, they are meant for aerobic bio-reaction processes. See-saw bioreactor has been developed at Indian Institute of Technology Kharagpur. Bio-reaction is a slow process and takes days or at least hours, to complete. Nevertheless, there is some heat generation (or absorption) and change in pH value of the bioreactor fluid over the time takes place. Temperature and pH values of the bioreactor fluid are considered as environmental variables and need to be controlled within a tight band for the micro-organisms to survive. Besides chances of contamination, organic in nature, are there and require to be monitored. Dissolved oxygen content of the bioreactor fluid is probably the most important single process variable for maximizing the product yield. The fan speed in the continuous stirred tank reactor or the see-sawing rate in the see-saw bioreactor acts as the corresponding control variable. Thus, a bio-reaction process requires continuous measurement of the dissolved oxygen content, temperature and pH value of the bioreactor fluid. There are other variables which cannot be as easily measured. If a mathematical model of the bio-reaction process could be developed, then one could go for observer based ‘soft sensing’.