Symbiosis Among Lactic Streptococci

IDENTIFICATION OF STIMULATORY FACTOR INVOLVED IN SYMBIOTIC GROWTH OF STREPTOCOCCUS LACTIS AND STREPTOCOCCUS CREMORIS

“…Earlier studies (Dahiya and Speck, 1962) showed that S. lactis (FlA) produced a certain compound(s) while growing in milk, which was stimulatory for S. cremoris (F2A). The compound involved was presumed to be of row molecular weight, as it was lost on dialysis through cellophane tubing.…”

“…The isolation and maintenance of the streptococci used in the present study were described earlier (Dahiya and Speck, 1962). S. lactis FIA grew relatively slowly in litmus milk, requiring about 72 hr at 22 C to produce sufficient acid for coagulation; S. cremoris F2A was a faster-growing culture that acid-coagulated litmus milk in 24 hr at 22 C. Preparation of filtrate from milk cultures of these strains, the adsorption and elution of the active material from a resin column (Amberlite IR 120, H+ cycle), the hydrolysis of different culture fractions, and the method used for tube assay have also been described previously (Dahiya and Speck, 1962).…”

“…However, the associative growth resulted in much-enhanced acid production over that produced by the single-strain cultures. Some of the characteristics of the stimulatory factor(s) involved in a symbiotic relationship among strains of lactic streptococci during growth in milk were studied by Dahiya and Speck (1962). The present study deals with the isolation and identification of the factor from Streptococcus lactis which provided the main source of stimulation in the symbiotic relationship between it and S. cremoris.…”

The Selection and Use of Some Micro‐organisms for the Manufacture of Fermented and Acidified Milk Products

“…Generally several strains or several species of lactic acid bacteria are cultivated together. The behaviour of the mixture is different from that of each of the pure strains taken individually and cannot be foreseen in advance (Dahiya & Speck, 1962).…”

Section B. Cheese and butter starters

“…The active compound was dialysable and could be adsorbed to Amberlite IRC (H+) resin and eluted with aqueous ammonia. Acid hydrolysis destroyed part of the activity, but the active compound has not been identified (383). It was also found that extracts of autolysates of Str.…”