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Microbial Enzymes in Food Applications
History of Progress
Swati S. Mishra,1,* Ramesh C. Ray,2 Cristina M. Rosell3 and Debabrata Panda1
2 ICAR-Regional Centre of Central Tuber Crops Research Institute, Bhubaneswar 751019, India.
3 Food Science Department, Institute of Agrochemistry and Food Technology, Avda Agustín Escardino Paterna, Valencia, Spain; E-mail:
[email protected] * Corresponding author
It seems now clear that a belief in the functional importance of all enzymes found in bacteria is possible only to those richly endowed with faith.
—Marjory Stephenson (Biochemist)
Enzymes are very important for sustainability of life in all life forms. They act as catalysts in chemical reactions. Microbial enzymes are of great importance in the development of industrial bioprocesses as they play a crucial role as metabolic catalysts. Enzymes have been applied in food preservation for millennia, and today they are enabling various food industries to provide the quality and stability of their products, with increased production efficiency. Microbial enzymes in food applications have not only diversified the food industry but also produced economic assets. The increasing demand for sustainable food has given an increasing drive to the use of microbial enzymes, knowingly or unknowingly since ages. Microorganisms have always been the largest and useful sources of many enzymes (Demain, 2008). They also provide environmental-friendly products to consumers, reducing consumption in energy, water and raw materials and generating less waste. Enzymes contribute to industrial processes by reducing energy consumption and maximizing its efficiency while contributing to its sustainability profile.
Although not in isolated form, enzymes have been used traditionally in dairy, baking, brewing and winemaking for centuries (Kirk et al., 2002). Their applications keep the bread soft and fresh for long, increase the dough volume and give a crispy crust (Rosell and Dura, 2016). Since time immemorial, enzymes are used in beer and wine to lower the calorie and alcoholic contents and also for more clarity and enhancement of flavour. Though used for centuries unknowingly, the revolution in food industry has been established by the use of enzymes or a whole microbial cell as the biocatalyst. The microbial enzyme has a high industrial and commercial application (Adrio and Demain, 2005). Microbes have proven to be the most useful and largest source of enzymes (Demain and Adrio, 2008). The current article covers the major developments in essential microbial enzyme production and applications in food industry.
An enzyme in purified form is a protein which is synthesized as an intra- and extra-cellular compound and may or may not possess non-protein prosthetic group (Vallery and Devonshire, 2003). Enzymes enhance the reaction rate with high specificity as they catalyzes biochemical reactions. All enzymes known (except ribozymes) are proteins which are high molecular-weight compounds made from chains of amino acids linked by peptide bonds. Enzymes are classified by the type of reaction they catalyse and the substance (called substrate) they act upon. It is customary to attach the suffix ‘ase’ to the name of the principal substrate upon which the enzyme acts (Bennett and Frieden, 1969). For example, lactose is acted upon by lactase, proteins by proteases and lipids by lipases. Also enzymes have common names, such as papain, from papaya.
Enzymes in history were known as ‘biocatalysts’, which helped to accelerate the biological or biochemical reaction. The term ‘enzyme’ was first used in 1877, by Wilhelm Friedrich Kuhne, Professor of Physiology at University of Heidelberg, in his paper to the HeidelbergerNatur-Historischen und Medizinischen Verein, suggesting that such non-organized ferments should be called enzymes (Kuhne, 1876). It was derived from a Greek term ‘ενζυμον’ meaning ‘in leaven’ or ‘in yeast’ (Kuhne, 1877). Though enzymes have been used by mankind since centuries, they were technically termed as ‘enzymes’ only in the 18th century.
Before the nature and function of enzymes were understood, the practical applications were established as there were many ancient uses of enzymes, like barley malt for conversion of starch in brewing or calf stomach as a catalyst in the manufacture of cheese. Later on, many scientists reported on enzymes in different forms, for example, Spallanzani in about 1783, showed that the gastric juice secreted by cells could digest meat in vitro and whose active substance was named as pepsin by Schwann in 1836 (Perham, 1976). The first enzyme to be discovered was ‘diastase’ by a French scientist, Payen in the year 1833, when he found it catalyzes the breakdown of starch into glucose in malt. James B. Sumner of Cornell University obtained the first enzyme in pure form, called ‘urease’, in 1926. He received the Nobel Prize in 1947 for isolating and crystallizing the enzyme urease from jack bean. The discovery of a complex procedure for isolating pepsin by John H. Northrop and Wendell M. Stanley of the Rockefeller Institute for Medical Research earned them the 1947 Nobel Prize as well. This precipitation technique has been used to crystallize several enzymes (Pfeiffer, 1954). Table 1 shows the periodic development of microbial enzymes over the centuries.
* Source: Rose (1980), Behera and Ray (2015), Joshi and Satyanarayana (2015), Panda and Ray (2015), Panda et al. (2016)
Like all living cells, microbes also produce enzymes which are hydrolyzing, oxidizing, reducing or metabolic in nature, but the amount of enzyme produced differs in various species and strains. Hence for commercial production of specific enzymes, a particular strain is to be selected that has the maximum enzyme activity. Enzymes from microbial sources are more advantageous than their equivalents from plant and animal sources because of lower production cost as compared to others, production on a large-scale, better scope for genetic manipulation, rapid culture development, less material use, being environment friendly and due to a wide range of physical and chemical characteristics; hence, they are preferred in various industrial applications (Hasan et al., 2006). Important progress in the food industry is mainly attributed to the use of microbial enzymes. Nowadays, enzymes are increasingly use...
