Characterization And Purification Of Milk Clotting Enzyme From Lactic Acid Bacteria And It’s Application
Lactic acid bacteria (LAB) are known to produce extracellular enzymes that could be exploited for use in the dairy industry. Ten of 135 LAB isolated from different food sources produced extracellular enzyme of which six LAB isolates from Malaysian fermented foods (belacan, pekasam, budu, fermente...
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| Summary: | Lactic acid bacteria (LAB) are known to produce extracellular enzymes that could be
exploited for use in the dairy industry. Ten of 135 LAB isolated from different food
sources produced extracellular enzyme of which six LAB isolates from Malaysian
fermented foods (belacan, pekasam, budu, fermented buffalo milk and fermented
ginger) produced milk clotting activity (MCA). The MCA of the isolates ranged
between 30 and 50 SU/ml. The six isolates were identified by (API 50CHL) and
confirmed by the sequence analysis of 16S rDNA gene as Pediococcus acidilactici
SH, Lactobacillus paracasei CF1 Lactobacillus plantaruni ASC 1, L. plantaraan H6M,
Enterococcus faecium FFA, and Enterococcus faecium FFB. High MCA of 50.0 (SU/
ml) and 43.0 (SU/ ml) were shown by P. acidilactici SH and L. paracasei CF1,
respectively and were chosen for further analysis. Nitrogen sources, pH and
temperature significantly (p<0.05) influenced the MCA of enzymes produced by the
two LAB. Among the nitrogen sources namely, casein, tryptophan, trypticase peptone
and tryptone soya added to the enzyme production media, casein was found to
increase significantly (p<0.05) the MCA to (75SU/ ml) for P. acidilactici SH and 57.0
(SU/ ml) for L. paracasei CFI, at casein concentration 0.5 % and 1%, respectively.
The optimum pH and temperatures for maximum MCA were pH 6 and 50 °C for P.
acidilactici SH and pH 7 and 40 °C for L. paracasei CFI. SDS-PAGE of the purified
enzyme by ammonium sulfate and Sephadex G-50 fine produced bands with a
molecular weight of approximately 30 KDa and 27 KDa for P. acidilactici SH and L.
paracasei CF1, respectively. Urea SDS-PAGE analysis showed that MCE produce by
L. paracasei CF1 hydrolysed x-casein and incomplete degradation of a and 0-casein,
while MCE produce by P. acidilactici SH was active on x-casein but not on a and ßcasein.
Addition of freeze dried enzyme (1% w/v) to goat milk and skim milk (12.5%
w/v) successfully produced a dadih with the acceptable texture properties. This study
indicates the possibility of exploiting LAB from food sources for the production of
milk-clotting enzymes for dairy production |
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