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Factors Affecting Growth Of Proteinase Positive And Proteinase Negative Streptococcus Cremoris Uc310 In Ultrafiltered Milk Retentate, Brent Karl Pope
Factors Affecting Growth Of Proteinase Positive And Proteinase Negative Streptococcus Cremoris Uc310 In Ultrafiltered Milk Retentate, Brent Karl Pope
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Whole milks were adjusted to pH 5.8, 6.2, or 6. 7 with HCl and batch pasteurized at 63°C for 30 min. Each was concentrated 5:1 (40% total solids) through a single tube polysulfone membrane Abcor ultrafiltration unit. Lactose (L), casein hydrolysate (CH), and one of two brands of yeast extract (YE1, YE2) were added into cooled retentates at 0.1, 0.3, 0.5, 0. 7 or 0.9% and equilibrated overnight at 4°C. Five percent proteinase positive (Prt+) Streptococcus cremoris UC 310+ (v/w) milk based culture was added. Unfortified retentate was also inoculated with 0.1, 0.3, 0.5, 0. 7 or 0.9% starter and …
Effect Of Proteolytic Enzymes On Transfection And Transformation Of Streptococcus Lactis Protoplasts And Transformation Of Streptococcus Cremoris, Steven A. Woskow
Effect Of Proteolytic Enzymes On Transfection And Transformation Of Streptococcus Lactis Protoplasts And Transformation Of Streptococcus Cremoris, Steven A. Woskow
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
The effect of proteolytic enzymes on the transformation and transfection of Streptococcus lactis LM2301 protoplasts was examined in an attempt to eliminate the variability observed. By using both chymotrypsin and mutanolysin to form protoplasts followed by spread plating, consistent frequencies of 104 to 105 transformants per μg of pGB301 DNA, and 105 transfectants per μg of c2 bacteriophage DNA where achieved. Optimum transformation and transfection frequencies were obtained when 16 h cultures were treated simultaneously with 25 U/ml mutanolysin and 1.25 U/ml chymotrypsin for 15 min. Trypsin and pronase in conjunction with mutanolysin also increased transformation frequencies higher than when …