Chymosin and other milk coagulants: sources and biotechnological interventions

Abstract

Calf rennet, which consists of over 90% chymosin, is commonly used in cheese industries for the curdling of milk. Various animal, plant and microbial sources have been exploited as possible alternatives to calf rennet. The coagulating properties of the enzymatic preparations (coagulants) from these sources differ in terms of their physicochemical factors. The cheese industry has always sought out novel and stable enzyme sources, and recombinant chymosin has been found to be an effective alternative since it possesses several advantages over plant and microbial milk-clotting enzymes. This paper reviews the use of various milk coagulants, especially animal coagulants, for cheese making. Advancements in genetic and protein engineering to produce recombinant chymosin are discussed in addition to evaluating its identity to the rennet available from natural sources.

Increasing recombinant protein production in Escherichia coli through metabolic and genetic engineering

“…Until 1990, chymosin was isolated from the abomasum or fourth stomach of the calf and lamb. Today, it is produced by genetically engineered strains, such as Escherichia coli, Aspergillus niger, Kluyveromyces lactis, or Pichia pastoris [96]. Industrial enzymes are used in various industrial segments.…”

Determination of the influence of high pressure processing on calf rennet using response surface methodology: Effects on milk coagulation

“…In the last two decades, several animal, microbial (produced by fermentation without using recombinant techniques, e.g. protease from Rhizomucor miehei) and plant coagulants have been considered as potential rennet substitutes (Dalgleish, 1992;Kumar, Grover, Sharma, & Batish, 2010;Rolet-R ep ecaud et al, 2013). However, the application of these enzymes for milk clotting may have some disadvantages, such as a reduction in manufacturing yield and the production of undesirable flavors Walstra et al, 2006).…”

Characterization of the non-coagulating enzyme fraction of different milk-clotting preparations

“…selected for their high milk-clotting activity and their low general proteolytic activity. Jacob, Jaros, and Rohm (2011) and Kumar, Grover, Sharma, and Batish (2010) recently reviewed the properties of the different milk-clotting enzymes and also compared the results with regard to cheese yield and cheese quality, such as texture, aroma and flavour. Sousa, Ardö, and McSweeney (2001) reviewed the role of milk-clotting enzymes, according to their source, on the initial hydrolysis of caseins in cheese e Cheddar, blue cheese, Parmigiano Reggiano, Serra da Estrela and Feta.…”

“…Various methods exist to extract and process milk-clotting enzymes as recently reviewed by Jacob et al (2011), Kumar et al (2010) and Mistry (2006), from small-scale production to largescale standardized commercial production. For traditional cheese making, especially in southern Europe, rennet and plant-derived coagulants are still produced on a small scale directly at the dairy according to a process that is specific to the cheese maker using traditional local procedures and is for his own use (Jacob et al, 2011).…”