Effect of tween series on growth and Cis-9, trans-11 conjugated linoleic acid production of Lactobacillus acidophilus F0221 in the presence of bile salts

Tween 80™-induced changes in fatty acid profile of selected mesophilic lactobacilli

Fatty acid profiles are crucial for the functionality and viability of lactobacilli used in food applications. Tween 80™, a common culture media additive, is known to influence bacterial growth and composition. This study investigated how Tween 80™ supplementation impacts the fatty acid profiles of six mesophilic lactobacilli strains (Lacticaseibacillus spp., Limosilactobacillus spp., Lactiplantibacillus plantarum). Analysis of eleven strains revealed 29 distinct fatty acids. Tween 80™ supplementation significantly altered their fatty acid composition. Notably, there was a shift towards saturated fatty acids and changes within the unsaturated fatty acid profile. While some unsaturated fatty acids decreased, there was a concurrent rise in cyclic derivatives like lactobacillic acid (derived from vaccenic acid) and dihydrosterculic acid (derived from oleic acid). This suggests that despite the presence of Tween 80™ as an oleic acid source, lactobacilli prioritize the synthesis of these cyclic derivatives from precursor unsaturated fatty acids. Myristic acid and dihydrosterculic acid levels varied across strains. Interestingly, palmitic acid content increased, potentially reflecting enhanced incorporation of oleic acid from Tween 80™ into membranes. Conversely, cis-vaccenic acid levels consistently decreased across all strains. The observed fatty acid profiles differed from previous studies, likely due to a combination of factors including strain-specific variations and growth condition differences (media type, temperature, harvesting point). However, this study highlights the consistent impact of Tween 80™ on the fatty acid composition of lactobacilli, regardless of these variations. In conclusion, Tween 80™ significantly alters fatty acid profiles, influencing saturation levels and specific fatty acid proportions. This work reveals key factors, including stimulated synthesis of lactobacillic acid, competition for oleic acid incorporation, and strain-specific responses to myristic and dihydrosterculic acids. The consistent reduction in cis-vaccenic acid and the presence of cyclic derivatives warrant further investigation to elucidate their roles in response to Tween 80™ supplementation.

Advances in research on microbial conjugated linoleic acid bioconversion

Conjugated linoleic acid (CLA) is a functional food ingredient with prebiotic properties that provides health benefits for various human pathologies and disorders. However, limited natural CLA sources in animals and plants have led microorganisms like Lactobacillus and Bifidobacterium to emerge as new CLA sources. Microbial conversion of linoleic acid to CLA is mediated by linoleic acid isomerase and multicomponent enzymatic systems, with CLA production efficiency dependent on microbial species and strains. Additionally, complex factors like LA concentration, growth status, culture substrates, precursor type, prebiotic additives, and co-cultured microbe identity strongly influence CLA production and isomer composition. This review summarizes advances in the past decade regarding microbial CLA production, including bacteria and fungi. We highlight CLA production and potential regulatory mechanisms and discuss using microorganisms to enhance CLA content and nutritional value of fermented products. We also identify primary microbial CLA production bottlenecks and provide strategies to address these challenges and enhance production through functional gene and enzyme mining and downstream processing. This review aims to provide a reference for microbial CLA production and broaden the understanding of the potential probiotic role of microbial CLA producers.

Efficient Biosynthesis of 10-Hydroxy-2-decenoic Acid Using a NAD(P)H Regeneration P450 System and Whole-Cell Catalytic Biosynthesis

10-Hydroxy-2-decenoic acid (10-HDA) is an α,β-unsaturated medium-chain carboxylic acid containing a terminal hydroxyl group. It has various unique properties and great economic value. We improved the two-step biosynthesis method of 10-HDA. The conversion rate of the intermediate product trans-2-decenoic acid in the first step of 10-HDA synthesis could reach 93.1 ± 1.3% by combining transporter overexpression and permeation technology strategies. Moreover, the extracellular trans-2-decenoic acid content was five times greater than the intracellular content when 2.0% (v/v) triton X-100 and 1.2% (v/v) tween-80 were each used. In the second step of 10-HDA synthesis, we regenerated NAD(P)H by overexpressing a glucose dehydrogenase with the P450 enzyme (CYP153A33/M228L-CPRBM3) in Escherichia coli, improving the catalytic performance of the trans-2-decenoic acid terminal hydroxylation. Finally, the yield of 10-HDA was 486.5 mg/L using decanoic acid as the substrate with two-step continuous biosynthesis. Our research provides a simplified production strategy to promote the two-step continuous whole-cell catalytic biosynthesis of 10-HDA and other α,β-unsaturated carboxylic acid derivatives.

Mucosa-adherent Pediococcus Pentosaceus I44 isolated from healthy human and effect of oleic acid on its probiotic properties

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A Gram-positive, catalase-negative cocci identified as Pediococcus pentosaceus I44 was isolated from the ileal tissue of a healthy Indian.

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This isolate exhibited good tolerance to gastrointestinal conditions and bile stress.

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Oleic acid and oleic acid containing compounds (tween-80, olive oil and sesame oil) were found to have a significant effect on the stress tolerance ability and surface properties of this isolate invitro.

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Pediococcus pentosaceus I44 represents the autochthonous gut bacterial community and understanding such isolates provide useful insights into their role in human metabolism and health.

With the aim of selectively isolating and understanding the cultivable lactic acid bacteria that are autochthonous to human gut, biopsy samples were collected from the terminal ileum and caecum of healthy volunteers who underwent routine colonoscopy procedure. The use of tissue samples (over stool samples) provides for a better expression of the autochthonous bacterial population of the human gut. The strains that were stable after many rounds of sub-culture were identified and studied further. One such ileal isolate, a Gram-positive, catalase-negative cocci was identified to be Pediococcus pentosaceus I44. It was studied for its gastric tolerance, bile tolerance and surface properties, and reported here. The effect of tween-80, oleic acid, extra virgin olive oil and sesame oil on the aforementioned properties of P. pentosaceus I44 was also analysed. The isolate was able to survive well in simulated gastric fluid of pH 3.0 followed by treatment in simulated intestinal fluid with a survival percentage of around 70%. It was, however, unable to withstand pH 2.0 even in the presence of supplements. It showed good tolerance to bile stress (1% w/v), and its cell surface was found to be hydrophilic. P. pentosaceus I44 showed good aggregation of 87% after 24 h, with oleic acid having a significant effect on the isolate's aggregation potential. P. pentosaceus I44 is one of the few mucosa-bound cultivable bacteria that are adapted for survival in human colon. Studying and analysing such isolates might provide useful insights into their role in metabolism and health.

Improvement of Enantiomeric l-Lactic Acid Production from Mixed Hexose-Pentose Sugars by Coculture of Enterococcus mundtii WX1 and Lactobacillus rhamnosus SCJ9

Among 39 pentose-utilizing lactic acid bacteria (LAB) selected from acid-forming bacteria from the midgut of Eri silkworm, the isolate WX1 was selected with the highest capability to produce optically pure l-lactic acid (l-LA) from glucose, xylose and arabinose with furfural-tolerant properties. The isolate WX1 was identified as Enterococcus mundtii based on 16S rDNA sequence analysis. The conversion yields of l-LA from glucose and xylose by E. mundtii WX1 were 0.97 and 0.68 g/g substrate, respectively. Furthermore, l-LA production by E. mundtii WX1 in various glucose-xylose mixtures indicated glucose repression effect on xylose consumption. The coculture of E. mundtii WX1 and Lactobacillus rhamnosus SCJ9, a homofermentative LAB capable of producing l-LA from glucose clearly showed an improvement of l-LA production from 30 g/L total glucose-xylose (6:4). The results from Plackett–Burman design (PBD) indicated that Tween 80, MnSO4 and yeast extract (YE) were three medium components that significantly influenced (p < 0.05) l-LA production using the coculture strategy in the presence of 2 g/L furfural. Optimal concentrations of these variables revealed by central composite design (CCD) and response surface methodology (RSM) were 20.61 g/L YE, 1.44 g/L Tween 80 and 1.27 g/L MnSO4. Based on the optimized medium with 30 g/L total glucose-xylose (6:4), the maximum experimental l-LA value of 23.59 g/L reflecting 0.76 g/g substrate were achieved from 48 h fermentation at 37 °C. l-LA produced by coculture cultivated under standard MRS medium and new optimized conditions were 1.28 and 1.53 times higher than that obtained from single culture by E. mundtii WX1, respectively. This study provides the foundations for practical applications of coculture in bioconversion of lignocellulose particularly glucose-xylose-rich corn stover to l-LA.

Rapid Evaluation and Optimization of Medium Components Governing Tryptophan Production by Pediococcus acidilactici TP-6 Isolated from Malaysian Food via Statistical Approaches

Tryptophan is one of the most extensively used amino acids in livestock industry owing to its effectiveness in enhancing the growth performance of animals. Conventionally, the production of tryptophan relies heavily on genetically modified Escherichia coli but its pathogenicity is a great concern. Our recent study demonstrated that a lactic acid bacterium (LAB), Pediococcus acidilactici TP-6 that isolated from Malaysian food was a promising tryptophan producer. However, the tryptophan production must enhance further for viable industrial application. Hence, the current study evaluated the effects of medium components and optimized the medium composition for tryptophan production by P. acidilactici TP-6 statistically using Plackett-Burman Design, and Central Composite Design. The optimized medium containing molasses (14.06 g/L), meat extract (23.68 g/L), urea (5.56 g/L) and FeSO4 (0.024 g/L) significantly enhanced the tryptophan production by 150% as compared to the control de Man, Rogosa and Sharpe medium. The findings obtained in this study revealed that rapid evaluation and effective optimization of medium composition governing tryptophan production by P. acidilactici TP-6 were feasible via statistical approaches. Additionally, the current findings reveal the potential of utilizing LAB as a safer alternative tryptophan producer and provides insight for future exploitation of various amino acid productions by LAB.

Cultivation media for lactic acid bacteria used in dairy products

This review aims to familiarize the reader with research efforts on the cultivation media of lactic acid bacteria (LAB). We have also included a brief discussion on standard ingredients used in LAB media and chemically defined media as related to bacterial growth requirements. Recent research has focused on modifying standard media for the enumeration, differentiation, isolation, and identification of starter cultures and probiotics. Even though large numbers of these media have been developed to serve dairy microbial control, they have failed to provide consistent results. The research consequently points to the need to develop a reliable lactobacilli growth medium for the dairy industry.

Optimized medium via statistical approach enhanced threonine production by Pediococcus pentosaceus TL-3 isolated from Malaysian food

BACKGROUND

Threonine is an essential amino acid that is extensively used in livestock industry as feed supplement due to its pronounced effect in improving the growth performance of animals. Application of genetically engineered bacteria for amino acid production has its share of controversies after eosinophils myalgia syndrome outbreak in 1980s. This has urged for continuous search for a food grade producer as a safer alternative for industrial amino acid production. Lactic acid bacteria (LAB) appear as an exceptional candidate owing to their non-pathogenic nature and reputation of Generally Recognized as Safe (GRAS) status. Recently, we have identified a LAB, Pediococcus pentosaceus TL-3, isolated from Malaysian food as a potential threonine producer. Thus, the objective of this study was to enhance the threonine production by P. pentosaceus TL-3 via optimized medium developed by using Plackett-Burman design (PBD) and central composite design (CCD).

RESULTS

Molasses, meat extract, (NH4)2SO4, and MnSO4 were identified as the main medium components for threonine production by P. pentosaceus TL-3. The optimum concentration of molasses, meat extract, (NH4)2SO4 and MnSO4 were found to be 30.79 g/L, 25.30 g/L, 8.59 g/L, and 0.098 g/L respectively based on model obtained in CCD with a predicted net threonine production of 123.07 mg/L. The net threonine production by P. pentosaceus TL-3 in the optimized medium was enhanced approximately 2 folds compared to the control.

CONCLUSIONS

This study has revealed the potential of P. pentosaceus TL-3 as a safer alternative to produce threonine. Additionally, the current study has identified the key medium components affecting the production of threonine by P. pentosaceus TL-3, followed by optimization of their concentrations by means of statistical approach. The findings of this study could act as a guideline for the future exploration of amino acid production by LAB.

Direct Growth Inhibitory Effect of Platelet Activating Factor C-16 and Its Structural Analogs on Mycobacteria

Mycobacterium tuberculosis, the causative agent of tuberculosis, is one of the leading causes of human deaths due to a single infectious agent. M. tuberculosis infection of the host initiates a local inflammatory response, resulting in the production of a range of inflammatory factors at the site of infection. These inflammatory factors may come in direct contact with M. tuberculosis and immune cells to activate different signaling pathways. One such factor produced in excess during inflammation is a phospholipid compound, Platelet Activating Factor C-16 (PAF C-16). In this study, PAF C-16 was shown to have a direct inhibitory effect on the growth of Mycobacterium bovis BCG (M. bovis BCG) and Mycobacterium smegmatis (M. smegmatis) in a dose- and time-dependent manner. Use of a range of PAF C-16 structural analogs, including the precursor form Lyso-PAF, revealed that small modifications in the structure of PAF C-16 did not alter its mycobacterial growth inhibitory properties. Subsequent experiments suggested that the attachment of aliphatic carbon tail via ether bond to the glycerol backbone of PAF C-16 was likely to play a vital role in its growth inhibition ability against mycobacteria. Fluorescence microscopy and flow cytometry using Propidium iodide (PI) indicated that PAF C-16 treatment had a damaging effect on the cell membrane of M. bovis BCG and M. smegmatis. Furthermore, the growth inhibitory effect of PAF C-16 was partially mitigated by treatment with membrane-stabilizing agents, α-tocopherol and Tween-80, which further suggests that the growth inhibitory effect of PAF C-16 was mediated through bacterial cell membrane damage.

Interrelation between Tween and the membrane properties and high pressure tolerance of Lactobacillus plantarum

Tween® 80 is a frequently used supplement of media for the cultivation of lactic acid bacteria. We investigated its effect on the cell physiology and stress tolerance of Lactobacillus (L.) plantarum. Data on the transcriptomic response to Tween 80 supplementation and its effects on cellular fatty acid profiles and growth characteristics are compared with data characterizing the effect of Tween 80, other Tween types and free fatty acids on the high hydrostatic pressure (HHP) tolerance of L. plantarum strain TMW 1.708. These include effects on cell viability, sub-lethal injury, metabolic activity, protein release and propidium iodide uptake. Tween 80 caused the downregulation of fatty acid biosynthesis and an increase in oleic acid and cyclopropane fatty acid levels in the cell membrane. Tween 20, Tween 80 and free oleic acid, but not Tween 40, Tween 60 and other free fatty acids, conferred resistance against HHP. Tween 80 diminished pressure-induced loss of metabolic activity, protein release and uptake of propidium iodide. However, loss of cell viability exceeded by far membrane permeabilization, suggesting that membrane permeabilization, which has frequently been postulated as a major factor in HHP inactivation of microbes, is not necessarily required for HHP-induced cell death of Lactobacillus plantarum.

Bacterial conjugated linoleic acid production and their applications

Conjugated linoleic acid (CLA) has been shown to exert various potential physiological properties including anti-carcinogenic, anti-obesity, anti-cardiovascular and anti-diabetic activities, and consequently has been considered as a promising food supplement. Bacterial biosynthesis of CLA is an attractive approach for commercial production due to its high isomer-selectivity and convenient purification process. Many bacterial species have been reported to convert free linoleic acid (LA) to CLA, hitherto only the precise CLA-producing mechanisms in Propionibacterium acnes and Lactobacillus plantarum have been illustrated completely, prompting the development of recombinant technology used in CLA production. The purpose of the article is to review the bacterial CLA producers as well as the recent progress on describing the mechanism of microbial CLA-production. Furthermore, the advances and potential in the heterologous expression of CLA genetic determinants will be presented.

Strategies for Producing and Incorporating Conjugated Linoleic Acid–Rich Oils in Foods

Conjugated linoleic acid (CLA) is in ruminant-derived foods and is known to combat obesity-related diseases. However, CLA levels in a healthy diet are too low to produce a clinical effect. Therefore, CLA has been produced by linoleic isomerization through fermentation and chemical catalysis. Many of these techniques are not practical for food production, but a recent development has enabled production of CLA-rich triglyceride vegetable oils from high linoleic acid oils by a minor modification of conventional food-oil processing techniques. These oils were used to produce common lipid-based food, such as margarine, shortenings, and salad dressings, whose quality was enhanced by the presence of CLA-rich oil and provided a significant CLA source. Meat and egg CLA content and subsequent food quality can also be increased by addition of dietary CLA. However, consumer awareness of CLA benefits needs to increase prior to commercial-scale production of CLA-rich oil.

Cultivation of stable, reproducible microbial communities from different fecal donors using minibioreactor arrays (MBRAs)

BACKGROUND

Continuous-flow culture models are one tool for studying complex interactions between members of human fecal microbiotas because they allow studies to be completed during an extended period of time under conditions where pH, nutrient availability, and washout of waste products and dead cells can be controlled. Because many of the existing well-validated continuous-flow models are large and complex, we were interested in developing a simpler continuous-flow system that would allow microbial community dynamics to be examined in higher throughput while still maintaining complex microbial communities. To this end, we developed minibioreactor arrays (MBRAs), small volume bioreactors (15 ml) that allow simultaneous cultivation of up to 48 microbial communities in a single anaerobic chamber.

RESULTS

We used MBRA to characterize the microbial community dynamics of replicate reactors inoculated from three different human fecal donors and reactors seeded with feces pooled from these three donors. We found that MBRA could be used to efficiently cultivate complex microbial communities that were a subset of the initial fecal inoculum (15-25 % of fecal OTUs initially observed). After an initial acclimation period of approximately 1 week, communities in each reactor stabilized and exhibited day-to-day variation similar to that observed in stable mouse fecal communities. Replicate reactors were predominately populated by shared core microbial communities; variation between replicate reactors was primarily driven by shifts in abundance of shared operational taxonomic units (OTUs). Consistent with differences between fecal donors, MBRA communities present in reactors seeded with different fecal samples had distinct composition and structure.

CONCLUSIONS

From these analyses, we conclude that MBRAs can be used to cultivate communities that recapitulate key features of human fecal communities and are a useful tool to facilitate higher-throughput studies of the dynamics of these communities.

Probiotic suppression of the H. pylori-induced responses by conjugated linoleic acids in a gastric epithelial cell line

Conjugated linoleic acids (CLA) produced by Lactobacillus acidophilus was reported to decrease the activation of nuclear factor-kappa B. CLA was suggested as one of the anti-inflammatory molecular mechanisms of probiotics. In the present study, the effects of CLA on H. pylori-induced multiple responses were evaluated. IL-8, TNF-α and iNOS were measured in mRNA and/or protein levels in AGS cells after pretreatment with CLA or CLA-containing conditioned medium (CM) produced by Lactobacillus acidophilus or Lactobacillus plantarum. The increased expressions of IL-8 mRNA/protein and TNF-α mRNA were significantly suppressed by pretreatment with CM or CLA. The levels of IL-8 protein and TNF-α mRNA were suppressed by CM pretreatment better than CLA. The expression of iNOS mRNA was also significantly inhibited by CM pretreatment. These results suggest that the suppression of multiple mediators by CLA-containing CM plays a key role in the anti-inflammatory and anti-carcinogenic effects of probiotics on H. pylori infection.