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Improved production of live cells of Lactobacillus rhamnosus by continuous cultivation using glucose-yeast extract medium

Ling LS, Mohamad R, Rahim RA, Wan HY, Ariff AB

J Microbiol, 2006 Aug;44(4):439-46.
PMID: 16953180

In this study, the growth kinetics of Lactobacillus rhamnosus and lactic acid production in continuous culture were assessed at a range of dilution rates (0.05 h(-1) to 0.40 h(-1)) using a 2 L stirred tank fermenter with a working volume of 600 ml. Unstructured models, predicated on the Monod and Luedeking-Piret equations, were employed to simulate the growth of the bacterium, glucose consumption, and lactic acid production at different dilution rates in continuous cultures. The maximum specific growth rate of L. rhamnosus, mu-max, was estimated at 0.40 h(-1), and the Monod cell growth saturation constant, Ks, at approximately 0.25 g/L. Maximum cell viability (1.3 x 10(10) CFU/ml) was achieved in the dilution rate range of D = 0.28 h(-1) to 0.35 h(-1). Both maximum viable cell yield and productivity were achieved at D = 0.35 h(-1). The continuous cultivation of L. rhamnosus at D = 0.35 h(-1) resulted in substantial improvements in cell productivity, of 267% (viable cell count) that achieved via batch cultivation.

Matched MeSH terms: Lactobacillus rhamnosus/growth & development*; Lactobacillus rhamnosus/metabolism
Microencapsulation of Lactobacillus rhamnosus GG with flaxseed mucilage using co-extrusion technique

Lai K, How Y, Pui L

J Microencapsul, 2021 Mar;38(2):134-148.
PMID: 33306440 DOI: 10.1080/02652048.2020.1863490

AIM: This study aimed to evaluate the protective effect of flaxseed mucilage on the co-extrusion microencapsulation of Lactobacillus rhamnosus GG.
METHODS: Core flow rate, chitosan coating, and flaxseed mucilage concentration were optimised for the microencapsulation of L. rhamnosus. The microbeads were characterised and evaluated on microencapsulation efficiency and cell released after 6 h of sequential digestion.
RESULTS: The optimised parameters for the L. rhamnosus microencapsulation were 1.0 mL/min core flow rate, 0.4% (w/v) chitosan coating, and 0.4% (w/v) flaxseed mucilage. The L. rhamnosus microbeads with flaxseed mucilage in core and wall materials had a smooth surface with 781.3 µm diameter, the highest microencapsulation efficiency (98.8% w/w), lowest swelling (5196.7% w/w) and erosion ratio (515.5% w/w), and least cell release (<40% w/w) with 9.31 log10 CFU mL-1 after sequential digestion.
CONCLUSIONS: This study showed the protective capacity of flaxseed mucilage towards the L. rhamnosus GG during microencapsulation and gastrointestinal environment.

Matched MeSH terms: Lactobacillus rhamnosus/cytology*; Lactobacillus rhamnosus/metabolism
Fulltext Growth optimization of Lactobacillus rhamnosus FTDC 8313 and the production of putative dermal bioactives in the presence of manganese and magnesium ions

Lew LC, Liong MT, Gan CY

J Appl Microbiol, 2013 Feb;114(2):526-35.
PMID: 23082775 DOI: 10.1111/jam.12044

AIMS: The study aimed to optimize the growth and evaluate the production of putative dermal bioactives from Lactobacillus rhamnosus FTDC 8313 using response surface methodology, in the presence of divalent metal ions, namely manganese and magnesium.
METHODS AND RESULTS: A central composite design matrix (alpha value of ± 1.414) was generated with two independent factors, namely manganese sulphate (MnSO(4) ) and magnesium sulphate (MgSO(4) ). The second-order regression model indicated that the quadratic model was significant (P < 0.01), suggesting that the model accurately represented the data in the experimental region. Three-dimensional response surfaces predicted an optimum point with maximum growth of 10.59 log(10) CFU ml(-1) . The combination that produced the optimum point was 0.80 mg ml(-1) MnSO(4) and 1.09 mg ml(-1) MgSO(4) . A validation experiment was performed, and data obtained showed a deviation of 0.30% from the predicted value, ascertaining the predictions and the reliability of the regression model used. Effects of divalent metal ions on the production of putative dermal bioactives, namely hyaluronic acid, diacetyl, peptidoglycan, lipoteichoic acid and organic acids in the region of optimized growth, were evaluated using 3D response surfaces generated. Evaluation based on the individual and interaction effects showed that both manganese and magnesium played an important role in the production of these putative bioactives.
CONCLUSIONS: Optimum growth of Lact. rhamnosus FTDC 8313 in reconstituted skimmed milk was achieved at 10.59 log(10) CFU ml(-1) in the presence of MnSO(4) (0.80 mg ml(-1) ) and MgSO(4) (1.09 mg ml(-1) ). Production of putative dermal bioactive and inhibitory compounds including hyaluronic acid, diacetyl, peptidoglycan, lipoteichoic acid and organic acids at the regions of optimized growth showed potential dermal applications.
SIGNIFICANT AND IMPACT OF THE STUDY: This research can serve as a fundamental study to further evaluate the potential of Lactobacillus strains in non-gut-related roles such as dermal applications.

Matched MeSH terms: Lactobacillus rhamnosus/drug effects; Lactobacillus rhamnosus/growth & development*; Lactobacillus rhamnosus/metabolism*
Mn(2+) and Mg(2+) synergistically enhanced lactic acid production by Lactobacillus rhamnosus FTDC 8313 via affecting different stages of the hexose monophosphate pathway

Lew LC, Choi SB, Tan PL, Liong MT

J Appl Microbiol, 2014 Mar;116(3):644-53.
PMID: 24267975 DOI: 10.1111/jam.12399

The study aimed to evaluate the effects of Mn(2+) and Mg(2+) on lactic acid production using response surface methodology and to further study their effects on interactions between the enzymes and substrates along the hexose monophosphate pathway using a molecular modelling approach.

Matched MeSH terms: Lactobacillus rhamnosus/drug effects; Lactobacillus rhamnosus/enzymology*
The potential hazards of Aspergillus sp. in foods and feeds, and the role of biological treatment: a review

Sheikh-Ali SI, Ahmad A, Mohd-Setapar SH, Zakaria ZA, Abdul-Talib N, Khamis AK, et al.

J Microbiol, 2014 Oct;52(10):807-18.
PMID: 25269603 DOI: 10.1007/s12275-014-4294-7

The contamination of food and feed by Aspergillus has become a global issue with a significant worldwide economic impact. The growth of Aspergillus is unfavourable to the development of food and feed industries, where the problems happen mostly due to the presence of mycotoxins, which is a toxic metabolite secreted by most Aspergillus groups. Moreover, fungi can produce spores that cause diseases, such as allergies and asthma, especially to human beings. High temperature, high moisture, retarded crops, and poor food storage conditions encourage the growth of mold, as well as the development of mycotoxins. A variety of chemical, biological, and physical strategies have been developed to control the production of mycotoxins. A biological approach, using a mixed culture comprised of Saccharomyces cerevisiae and Lactobacillus rhamnosus resulted in the inhibition of the growth of fungi when inoculated into fermented food. The results reveal that the mixed culture has a higher potential (37.08%) to inhibit the growth of Aspergillus flavus (producer of Aflatoxin) compared to either single culture, L. rhamnosus NRRL B-442 and S. cerevisiae, which inhibit the growth by 63.07% and 64.24%, respectively.

Matched MeSH terms: Lactobacillus rhamnosus/growth & development; Lactobacillus rhamnosus/physiology*
Fulltext Probiotic Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14 exhibit strong antifungal effects against vulvovaginal candidiasis-causing Candida glabrata isolates

Chew SY, Cheah YK, Seow HF, Sandai D, Than LT

J Appl Microbiol, 2015 May;118(5):1180-90.
PMID: 25688886 DOI: 10.1111/jam.12772

This study investigates the antagonistic effects of the probiotic strains Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14 against vulvovaginal candidiasis (VVC)-causing Candida glabrata.

Matched MeSH terms: Lactobacillus rhamnosus/physiology*
In vitro modulation of probiotic bacteria on the biofilm of Candida glabrata

Chew SY, Cheah YK, Seow HF, Sandai D, Than LT

Anaerobe, 2015 Aug;34:132-8.
PMID: 26028405 DOI: 10.1016/j.anaerobe.2015.05.009

A conspicuous new concept of pathogens living as the microbial societies in the human host rather than free planktonic cells has raised considerable concerns among scientists and clinicians. Fungal biofilms are communities of cells that possess distinct characteristic such as increased resistance to the immune defence and antimycotic agents in comparison to their planktonic cells counterpart. Therefore, inhibition of the biofilm may represent a new paradigm for antifungal development. In this study, we aim to evaluate the in vitro modulation of vulvovaginal candidiasis (VVC)-causing Candida glabrata biofilms using probiotic lactobacilli strains. Probiotic Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14 were shown to have completely inhibited C. glabrata biofilms and the results were corroborated by scanning electron microscopy (SEM), which revealed scanty structures of the mixed biofilms of C. glabrata and probiotic lactobacilli strains. In addition, biofilm-related C. glabrata genes EPA6 and YAK1 were downregulated in response to the probiotic lactobacilli challenges. The present study suggested that probiotic L. rhamnosus GR-1 and L. reuteri RC-14 strains inhibited C. glabrata biofilm by partially impeding the adherence of yeast cells and the effect might be contributed by the secretory compounds produced by these probiotic lactobacilli strains. Further investigations are required to examine and identify the biofilm inhibitory compounds and the mechanism of probiotic actions of these lactobacilli strains.

Matched MeSH terms: Lactobacillus rhamnosus/growth & development*
Microencapsulation of alginate-immobilized bagasse with Lactobacillus rhamnosus NRRL 442: enhancement of survivability and thermotolerance

Shaharuddin S, Muhamad II

Carbohydr Polym, 2015 Mar 30;119:173-81.
PMID: 25563958 DOI: 10.1016/j.carbpol.2014.11.045

The aim of this research was to enhance the survivability of Lactobacillus rhamnosus NRRL 442 against heat exposure via a combination of immobilization and microencapsulation processes using sugarcane bagasse (SB) and sodium alginate (NaA), respectively. The microcapsules were synthesized using different alginate concentration of 1, 2 and 3% and NaA:SB ratio of 1:0, 1:1 and 1:1.5. This beneficial step of probiotic immobilization before microencapsulation significantly enhanced microencapsulation efficiency and cell survivability after heat exposure of 90°C for 30s. Interestingly, the microcapsule of SB-immobilized probiotic could obtain protection from heat using microencapsulation of NaA concentration as low as 1%. SEM images illustrated the incorporation of immobilized L. rhamnosus within alginate matrices and its changes after heat exposure. FTIR spectra confirmed the change in functional bonding in the presence of sugarcane bagasse, probiotic and alginate. The results demonstrated a great potential in the synthesis of heat resistant microcapsules for probiotic.

Matched MeSH terms: Lactobacillus rhamnosus/cytology*; Lactobacillus rhamnosus/drug effects
Fulltext Evaluation of probiotic potential and anti-hyperglycemic properties of a novel Lactobacillus strain isolated from water kefir grains

Koh WY, Utra U, Ahmad R, Rather IA, Park YH

Food Sci Biotechnol, 2018 Oct;27(5):1369-1376.
PMID: 30319846 DOI: 10.1007/s10068-018-0360-y

A total of eight strains of lactic acid bacteria were isolated from water kefir grains and assessed for their in vitro α-glucosidase inhibitory activity. Lactobacillus mali K8 demonstrated significantly higher inhibition as compared to the other strains, thus was selected for in vitro probiotic potential characterization, antibiotic resistance, hemolytic activity and adaptation to pumpkin fruit puree. L. mali K8 demonstrated tolerance to pH 2.5 and resisted the damaging effects of bile salts, pepsin and pancreatin, comparable to that of Lactobacillus rhamnosus GG ATCC 53103 (reference strain). Lack of hemolytic activity and susceptibility to the five standard antibiotics indicated the safety of the K8 strain. This strain showed singular properties to be used as starters in the pumpkin fruit puree fermentation. These preliminary in vitro tests indicated the safety and functionality of the K8 strain and its potential as a probiotic candidate.

Matched MeSH terms: Lactobacillus rhamnosus
Reduced neonatal regulatory T cell response to microbial stimuli associates with subsequent eczema in high-risk infants

Ismail IH, Boyle RJ, Mah LJ, Licciardi PV, Tang ML

Pediatr Allergy Immunol, 2014 Nov;25(7):674-84.
PMID: 25376403 DOI: 10.1111/pai.12303

Regulatory T cells (Treg) play an essential role in early immune programming and shaping the immune response towards a pro-allergic or tolerant state. We evaluated cord blood Treg and cytokine responses to microbial and non-microbial stimuli in infants at high risk of allergic disease and their associations with development of allergic disease in the first year.

Matched MeSH terms: Lactobacillus rhamnosus/immunology*