Proteinase Profiles of Lactococcus lactis ssp. cremoris Using High Performance Liquid Chromatography
1990; Elsevier BV; Volume: 73; Issue: 6 Linguagem: Inglês
10.3168/jds.s0022-0302(90)78811-x
ISSN1529-9066
AutoresC. J. Oberg, F.A. Khayat, G.H. Richardson,
Tópico(s)Protein Hydrolysis and Bioactive Peptides
ResumoProteinase-positive or proteinase-negative lActococcus lactis ssp.cremoris cultures propagated in M17 broth were centrifuged, washed, mixed with 2.5% rennet-casein solution, and incubated at 30•C for 24 h.High perfonnance liquid chromatography analysis of the filtered extracts was conducted using an acetonitrile solvent gradient.Four major peaks, eluting at 8, 13, 19, and 25 min, were selected to characterize 26 strains.These four peaks were totaled to indicate the amount of casein solubilization.A fifth peak of soluble casein, eluting at 34 min, exhibited marked decreases in peak area for many of the strains.Different profiles developed for each proteinasepositive strain and its proteinase-negative variant.Most proteinase-positive strains were more proteolytic than their proteinase-negative variants.Four strains were atypical, the proteinase-negative variant had larger peak area totals for the four peaks selected than the proteinase-positive parent strain.These results were consistent with previous yield studies for these strains.The HPLC casein test shows potential for selecting strains for maximum yield potential.
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