The Effect of Growth Medium pH towards Trypsin-Like Activity Produced by Lactic Acid Bacteria

ABSTRACT Methanethiol has been strongly associated with desirable Cheddar cheese flavor and can be formed from the degradation of methionine (Met) via a number of microbial enzymes. Methionine γ-lyase is thought to play a major role in the catabolism of Met and generation of methanethiol in several species of bacteria. Other enzymes that have been reported to be capable of producing methanethiol from Met in lactic acid bacteria include cystathionine β-lyase and cystathionine γ-lyase. The objective of this study was to determine the production, stability, and activities of the enzymes involved in methanethiol generation in bacteria associated with cheese making. Lactococci and lactobacilli were observed to contain high levels of enzymes that acted primarily on cystathionine. Enzyme activity was dependent on the concentration of sulfur amino acids in the growth medium. Met aminotransferase activity was detected in all of the lactic acid bacteria tested and α-ketoglutarate was used as the amino group acceptor. In Lactococcus lactis subsp. cremorisS2, Met aminotransferase was repressed with increasing concentrations of Met in the growth medium. While no Met aminotransferase activity was detected in Brevibacterium linens BL2, it possessed high levels of l-methionine γ-lyase that was induced by addition of Met to the growth medium. Met demethiolation activity at pH 5.2 with 4% NaCl was not detected in cell extracts but was detected in whole cells. These data suggest that Met degradation in Cheddar cheese will depend on the organism used in production, the amount of enzyme released during aging, and the amount of Met in the matrix.

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Optimization of an effective growth medium for culturing probiotic bacteria for applications in strict vegetarian food products

Functional Foods in Health and Disease ◽

10.31989/ffhd.v2i10.75 ◽

2012 ◽

Vol 2 (10) ◽

pp. 369 ◽

Cited By ~ 5

Author(s):

Manju Pathak ◽

Danik Martirosyan

Keyword(s):

Lactic Acid ◽

Lactic Acid Bacteria ◽

Growth Medium ◽

Culture Medium ◽

Culture Media ◽

Plant Seed ◽

Meat Extract ◽

Colony Forming Units ◽

Lactobacillus Lactis ◽

De Man

Background: This study aimed to modify de Man Rogosa Sharpe culture medium (termed MRS) for selective cultivation of probiotics strain for the consumption by the strictly vegetarian human population. Vegetarian probiotic foods by definition must be free from all animal-derived ingredients. This not only includes the product ingredients but the probiotic inoculum as well. Probiotic starter cultures are traditionally grown and stored in media containing milk or meat-derived ingredients. The presence of these ingredients makes the probiotic cell concentrates unsuitable for use in vegetarian products and thus creates the need for a growth medium which is free from animal-derived ingredients. Present study investigated the growth of a strain of Lactobacillus lactis in MRS. The present invention relates in general to a bacterial culture media, and more specifically a complex microbial culture media, based on plant seed powder extract in place of animal extract for probiotic bacterial growth.Methods: Lactobacillus lactis, a probiotic, was grown in standard MRS culture medium as well as in our various test media (TM) containing various vegetal source in place of beef extract, yeast extract and peptone as in case of MRS. The inoculated culture mediums were incubated at 37C for 72 hours and growth of probiotic is recorded at regular intervals. The growth was recorded as Colony Forming Units (CFUs).Results: The best growth of probiotic is observed in TM 2. TM 2 is the leguminous seed extract. Starter culture mediums for probiotics or other bacteria primarily contain protein from animal source. The possibility of using vegetal protein from TM 2 extract in place of peptones and meat extract for the nitrogen supplementation of culture media for the growth of lactic acid bacteria has been demonstrated. Conclusion: The absolute vegetarian culture medium containing TM 2 is better than standard MRS for the growth of probiotics.Abbreviations: de Man Rogosa Sharpe (MRS), Colony Forming Units (CFU), test media (TM), National Dairy Research Institute (NDRI), Tamarind seed powder (TSP), solid-state fermentation (SSF), Lactobacillus casei Shirota (LcS)Keywords: probiotics, lactic acid bacteria, vegetarian

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Utilization of Echium amoenum Extract as a Growth Medium for the Production of Organic Acids by Selected Lactic Acid Bacteria

Food and Bioprocess Technology ◽

10.1007/s11947-011-0564-0 ◽

2011 ◽

Vol 5 (6) ◽

pp. 2275-2279 ◽

Cited By ~ 6

Author(s):

Forough Jahandideh ◽

Seyed Mohammad Mousavi ◽

Seyed Hadi Razavi

Keyword(s):

Lactic Acid ◽

Lactic Acid Bacteria ◽

Organic Acids ◽

Growth Medium ◽

Echium Amoenum

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Preparation of Indigenous Lactic Acid Bacteria Starter Cultures for Large Scale Production of Fermented Milk

Digital Press Life Sciences ◽

10.29037/digitalpress.22327 ◽

2020 ◽

Vol 2 ◽

pp. 00010

Author(s):

Tyas Utami ◽

Amaralda Cindarbhumi ◽

Marcella C. Khuangga ◽

Endang S. Rahayu ◽

Muhammad Nur Cahyanto ◽

...

Keyword(s):

Lactic Acid ◽

Lactic Acid Bacteria ◽

Growth Medium ◽

Large Scale ◽

Starter Culture ◽

Viable Cell ◽

Fermented Milk ◽

Starter Cultures ◽

Mixed Cultures ◽

Freeze Dried

<div>Lactobacillus plantarum Dad 13, an indigenous probiotic was examined its ability to be used as a single starter culture or mixed cultures with Streptococcus thermophilus Dad 11 for milk fermentation. Both cultures were isolated from dadih, a traditional fermented buffalo milk. The purposes of this study were to produce indigenous lactic acid bacteria starter cultures using halal growth medium and evaluate their application on large scale fermented milk production. The halal medium was developed using natural compounds such as sucrose, meat peptone, mung bean sprout extract, tomato extract, and young coconut water. Meat peptone was prepared by hydrolysis of halal meat using crude bromelain. Lactic acid bacteria were grown in the halal growth medium then harvested, frozen and freeze-dried. A single freeze-dried starter culture of L. plantarum Dad 13 and frozen mixed cultures of L. plantarum Dad 13 and S. thermophilus Dad 11 were prepared for production of fermented milk drink and yogurt respectively in industrial scale. The growth of these lactic acid bacteria in halal growth medium increased the viable cell to two log cycles (109 CFU/mL) for L. plantarum Dad 13 and one log cycle for S. thermophilus Dad 11 (108 CFU/mL), respectively. The viable cell of freeze-dried L. plantarum Dad 13 and S. thermophilus Dad 11 were 7.57 x 1010 CFU/g and 6.35 x 109 CFU/g, respectively. The number of viable cells and pH of both fermented milk drink and yogurt products was relatively stable to 107 CFU/mL and 108 CFU/mL, respectively during cold storage for four to six weeks. The sensory characteristics of the products were comparable to the ones using commercial starter cultures. It can be concluded that these indigenous starter cultures can be applied for the production of probiotic fermented milk.</div>

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