Advertisement
Research-Article| Volume 72, ISSUE 3, P627-634, March 1989

Download started.

Ok

Monitoring the Degradation of Commercial Microbial Rennet Preparations1

      This paper is only available as a PDF. To read, Please Download here.

      Abstract

      Fractionation on a DEAE-Sephadex A-50 column was used to study the degradation of microbial rennets derived from Mucor miehei. A comparison was made between the crude culture filtrate, derived from the growth of the microorganism in submerged culture condition on wheat bran medium, and commercial preparation Marzyme and Rennilase. The elution protein profiles lacked some of the peaks associated with the crude culture filtrate however, the milk-coagulating activity eluted out at approximately the same NaCl molarity (.45 M). Each brand name product had a characteristic elution pattern, which did not vary between their thermostable and thermolabile enzyme preparations. With storage at 4°C the elution protein profiles of the thermolabile enzyme preparations changed in a distinctive manner characteristic of the brand name. With the Marzyme series, the milk-coagulating activity eluted out at the same NaCl molarity, whereas other established peaks increased in area. The milk-coagulating activity, from Rennilase, eluted from the column at a lower NaCl concentration (.35 M). The changes were evidence of enzyme degradation, which was manifested by a general decrease in specific enzyme activity. By using column chromatography it was possible to monitor the stages of degradation with time.

      References

        • Branner S.
        • Eigtved P.
        • Christensen M.
        • Thogersen H.
        Amino acid and NMR analysis of oxidized Mucor miehei rennet.
        Enzyme Eng. 1984; 7: 434
      1. Branner-Jorgensen, S., P. Schneider, and P. Eigtved. 1982. Thermal destabilization of microbial rennet. US Pat. 4,3 57,3 57.

        • Cheesman G.C.
        Rennet and cheesemaking.
        in: Birch G.G. Blakebrough N. Parker K.J. Enzymes and food processing. Appl. Sci. Publ. Ltd., London, Engl1980: 195
      2. Cornelius, D. A. 1982. Process for decreasing thethermal stability of microbial rennet. US Pat. 4,348,482.

        • Cruegar W.
        • Cruegar A.
        Brock T.D. Enzymes. Biotechnology: a textboox of industrial microbiology. Sci. Tech., Inc., Madison, WI1984
        • Difco Manual.
        Dehydrated culture media and reagents for microbiology.
        10th ed. Difco Labs., Detroit, MI.1984 (Page 1132)
      3. Reference deleted in proof

        • Etoh Y.
        • Shoun H.
        • Arima K.
        • Beppu T.
        Photooxidation of a hystidyl residue of milk-clotting acid protease, mucor rennin.
        J. Biochem. 1982; 91: 747
      4. Kokusho, Y., S. Higashi, H. Machida, and S. Iwasaki. 1976. Process for improving the quality of microbial rennet. US Pat. 3,950,221.

        • Lowry O.
        • Rosebrough N.J.
        • Farr A.L.
        • Randall R.J.
        Protein measurement with the folinphenol reagent.
        J. Biol. Chem. 1951; 193: 265
        • Miller G.L.
        • Blum R.
        • Glennon W.E.
        • Burton A.L.
        Measurement of carboxymethyl-cellulase activity.
        Anal. Biochem. 1960; 2: 127
        • Nelson J.H.
        Symposium: application of enzyme technology to dairy manufacturing.
        J. Dairy Sci. 1974; 58.: 1739
      5. Schleich, H. 1981. Removing esterase from microbial rennin. US Pat. 3,616,233.

        • Shehata A.E.
        • Ismail A.A.
        • Hegazi A.
        • Hamdy A.M.
        Fractionation of commercial rennetenzymes on Sephadex G-100.
        Milschwissenschaft. 1978; 33: 693
      6. Sternberg, M. 1976. Purification of industrial enzymes with polyacrylic acids. Process Biochem.September: 11.

        • Sternberg M.
        Microbial rennets.
        Adv. Appl. Microbiol. 1976; 20: 13 5