Industrial enzymes microbial enzyme production

V. L. Yarovenko Theory and Practice of Continuous Cultivation of Microorganisms in Industrial Alcoholic Processes. - Y. Miura Mechanism of Liquid Hydrocarbon Uptake by Microorganisms and Growth Kinetics. -J. E. Zajic, N. Kosaric, J. D. Brosseau Microbial Production of Hydrogen. - T.Enatsu, AShin-myo In vitro Synthesis of Enzymes. Physiological Aspects of Microbial Enzyme Production. 

Many chemical reactions in biological systems occur in the presence of enzymes. Enzymes are proteins or glycoproteins, and accelerate biological reactions by factors of a million or more. The progress in biotechnology has resulted in the expanding field of microbial enzyme production and applications, and increased numbers of industrial enzymes have been taken into use. 

Animal Proteases. These include the pancreatic trypsins and the rennets, which are produced in both ultrapure and industrial bulk qualities. Again, the prospects for large increases in supply depend on the political and agricultural policies that control the production of livestock for slaughter. Currently, these enzymes cannot meet demand on a world basis adequately, with the result that the more price sensitive users have increasing interest in microbial enzymes. 

Bacteria represent a promising source for the production of industrial enzymes. Bacterial cellulases are an especialfy interesting case in point. Many thermophilic bacterial species produce cellulases that are stable and active at high temperature, resistant to proteolytic attack, and stable to mechanical and chemical denaturation. However, cellulase productivities in bacteria are notoriously low compared to other microbial sources. In this paper bacterial enzyme production systems will be discussed with a focus on comparisons of the productivities of known bacterial cellulase producers. In an attempt to draw conclusions concerning the regulation of cellulase synthesis in bacterial systems, a tentative model for regulation in Acidothennus cellulofyticus has been developed. 

Tailoring Opportunities. There are many methods or approaches available to tailor enzyme products. Early in the history of enzyme companies, methods such as source selection, microbial strain selection, growth conditions, media, purification, and recovery systems, were primarily used to make each enzyme preparation unique. Later, immobilization, encapsulation, and chemical modification of the enzyme molecule itself were added as methods of tailoring enzymes to better fit industrial applications. Today, all of these methods are still being used, and now we have added genetic engineering to our tailoring expertises. 

Some of the traditionally used industrial enzymes (e.g., rennet and papain) are prepared from animal and plant sources. Recent developments in industrial enzyme production have emphasized the microbial enzymes (Frost 1986). Microbial enzymes are very heat stable and have a broader pH optimum. Most of these enzymes are made by submerged cultivation of highly developed strains of microorganisms. Developments in... 

The most widely used animal enzyme is chymosin which is used for milk clotting in the production of cheese. Well known plant enzymes include papain, bromelain and cereal malt. Microbial enzymes have been used in the fruit and cereal processing industries since the 1950 s and offer a less expensive source. Eor example, chymosin (a relatively expensive enzyme found in the stomach of calves) have been replaced by the microbial rennet in the production of cheese. 

Proteases are enzymes that break down protein molecules through peptide bond hydrolysis [1]. They are commercially employed in many industrial processes. In foods, proteases have two main applications in the processing of traditional food products and in the processing of new protein-based ingredients called functional foods [2]. Proteases are also used in other industrial segments such as leather industry, pharmaceutical, waste management, and the detergent industry. Currently, microbial proteases make up approximately 40% of total enzyme sales [3, 4]. 

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