Soybean-based functional food with vitamin B12-producing lactic acid bacteria

Fermented foods and beverages: a potential in situ vitamin B12 biofortification - a literature review

Millions of dollars have been increasingly spent on plant-based diets. Considering that vitamin B12 is obtained from the consumption of animal-derived foods, new sources of vitamin B12 and methods of food fortification are being eagerly sought. Therefore, this work aims to evaluate advances in situ fermentation processes of food and beverages produced on a large scale and industrial applications for obtaining cobalamin-rich products. Bibliometric analysis was performed and revealed that several studies report a great capacity for in situ biofortification of B12 in foods, mostly on the use of propionic (PB) and lactic (LAB) bacteria. In this context, market potentials for such products, the main microorganisms, including simultaneous cultures, and their respective applications have been presented herein. Although knowledge on potential applications is still limited, field research has been increasingly conducted, thus revealing scientific and technological opportunities, both for the production and the stability of B12 found in plant-based foods.

The Impacts of Acidophilic Lactic Acid Bacteria on Food and Human Health: A Review of the Current Knowledge

The need to improve the safety/quality of food and the health of the hosts has resulted in increasing worldwide interest in acidophilic lactic acid bacteria (LAB) for the food, livestock as well as health industries. In addition to the use of acidophilic LAB with probiotic potential for food fermentation and preservation, their application in the natural disposal of acidic wastes polluting the environment is also being investigated. Considering this new benefit that has been assigned to probiotic microorganisms in recent years, the acceleration in efforts to identify new, efficient, promising probiotic acidophilic LAB is not surprising. One of these effots is to determine both the beneficial and harmful compounds synthesized by acidophilic LAB. Moreover, microorganisms are of concern due to their possible hemolytic, DNase, gelatinase and mucinolytic activities, and the presence of virulence/antibiotic genes. Hence, it is argued that acidophilic LAB should be evaluated for these parameters before their use in the health/food/livestock industry. However, this issue has not yet been fully discussed in the literature. Thus, this review pays attention to the less-known aspects of acidophilic LAB and the compounds they release, clarifying critical unanswered questions, and discussing their health benefits and safety.

Methylotrophic bacteria with cobalamin-dependent mutases in primary metabolism as potential strains for vitamin B12 production

Several bacterial species are known for their ability to synthesize vitamin B₁₂ but biotechnological vitamin B₁₂ production today is restricted to Pseudomonas denitrificans and Propionibacterium freudenreichii. Nevertheless, the rising popularity of veganism leads to a growing demand for vitamin B₁₂ and thereby interest in alternative strains which can be used as efficient vitamin B₁₂ sources. In this work, we demonstrate that methylotrophic microorganisms which utilize the ethylmalonyl-CoA pathway containing B₁₂-dependent enzymes are capable of active vitamin B₁₂ production. Several bacteria with an essential function of the pathway were tested for vitamin B₁₂ synthesis. Among the identified strains, Hyphomicrobium sp. DSM3646 demonstrated the highest vitamin B₁₂ levels reaching up to 17.9 ± 5.05 µg per g dry cell weight. These relatively high vitamin B₁₂ concentrations achieved in simple cultivation experiments were performed in a mineral methanol medium, which makes Hyphomicrobium sp. DSM3646 a new promising cobalamin-producing strain.

Exploring the genome of Lactobacillaceae spp. Sy-1 isolated from Heterotrigona itama honey

Background

Honey produced by Heterotrigona itama is highly preferred among consumers due to its high-value as a functional food and beneficial lactic acid bacteria (LAB) reservoir. Fructophilic lactic acid bacteria (FLAB) are a group of LAB with unique growth characteristics and are regarded as promising producers of bioactive compounds. Hence, it is not surprising that LAB, especially FLAB, may be involved with the excellent bioactivity of H. itama honey. With the trending consumer preference for H. itama honey coupled with increasing awareness for healthy food, the genomic background of FLAB isolated from this honey must, therefore, be clearly understood. In this study, one FLAB strain designated as Sy-1 was isolated from freshly collected H. itama honey. Its FLAB behavior and genomic features were investigated to uncover functional genes that could add value to functional food.

Methods

The fructophilic characteristics of strain Sy-1 were determined, and the genome was sequenced using Illumina iSeq100 and Oxford Nanopore. The average nucleotide identity and phylogenetic analyses based on 16S rRNA, 92 core genes, and whole-genome sequence were performed to unravel the phylogenetic position of strain Sy-1. NCBI Prokaryotic Genome Annotation Pipeline annotated the genome, while the EggNOG-mapper, BLASTKoala, and GHOSTKoala were used to add functional genes and pathways information.

Results

Strain Sy-1 prefers D-fructose over D-glucose and actively metabolizes D-glucose in the presence of electron acceptors. Genomic annotation of strain Sy-1 revealed few genes involved in carbohydrate transport and metabolism, and partial deletion of adhE gene, in line with the characteristic of FLAB. The 16S rRNA gene sequence of strain Sy-1 showed the highest similarity to unknown LAB species isolated from the gut of honeybees. The phylogenetic analyses discovered that strain Sy-1 belonged to the Lactobacillaceae family and formed a separate branch closer to type strain from the genera of Acetilactobacillus and Apilactobacillus. The ANI analysis showed the similarity of the closest relative, Apilactobacillus micheneri Hlig3^T. The assembled genome of Sy-1 contains 3 contigs with 2.03 Mbp and a 41% GC content. A total of 1,785 genes were identified, including 1,685 protein-coding genes, 68 tRNA, and 15 rRNA. Interestingly, strain Sy-1 encoded complete genes for the biosynthesis of folate and riboflavin. High-performance liquid chromatography analysis further confirmed the high production of folic acid (1.346 mg/L) by Sy-1.

Discussion

Based on phylogenetic and biochemical characteristics, strain Sy-1 should be classified as a novel genus in the family of Lactobacillaceae and a new member of FLAB. The genome information coupled with experimental studies supported the ability of strain Sy-1 to produce high folic acid. Our collective findings support the suitable application of FLAB strain Sy-1 in the functional food and pharmaceutical industries.

Functional bacterial cultures for dairy applications: towards improving safety, quality, nutritional and health benefit aspects

Traditionally, fermentation was used to preserve the shelf life of food. Currently, in addition to favouring food preservation, well standardized and controlled industrial processes are also aimed at improving the functional characteristics of the final product. In this regard, starter cultures have become an essential cornerstone of food production. The selection of robust microorganisms, well adapted to the food environment, has been followed by the development of microbial consortia that provide some functional characteristics, beyond their acidifying capacity, achieving safer, high‐quality foods with improved nutritional and health‐promoting properties. In addition to starters, adjunct cultures and probiotics, which normally do not have a relevant role in fermentation, are added to the food in order to provide some beneficial characteristics. This review focuses on highlighting the functional characteristics of food starters, as well as adjunct and probiotic cultures (mainly lactic acid bacteria and bifidobacteria), with a specific focus on the synthesis of metabolites for preservation and safety aspects (e.g. bacteriocins), organoleptic properties (e.g. exopolysaccharides), nutritional (e.g. vitamins) and health improvement (e.g. neuroactive molecules). Literature reporting the application of these functional cultures in the manufacture of foods, mainly those related to dairy production, such as cheeses and fermented milks, has also been updated.

Legumes and Legume-Based Beverages Fermented with Lactic Acid Bacteria as a Potential Carrier of Probiotics and Prebiotics

Fermentation is widely used in the processing of dairy, meat, and plant products. Due to the growing popularity of plant diets and the health benefits of consuming fermented products, there has been growing interest in the fermentation of plant products and the selection of microorganisms suitable for this process. The review provides a brief overview of lactic acid bacteria (LAB) and their use in fermentation of legumes and legume-based beverages. Its scope also extends to prebiotic ingredients present in legumes and legume-based beverages that can support the growth of LAB. Legumes are a suitable matrix for the production of plant-based beverages, which are the most popular products among dairy alternatives. Legumes and legume-based beverages have been successfully fermented with LAB. Legumes are a natural source of ingredients with prebiotic properties, including oligosaccharides, resistant starch, polyphenols, and isoflavones. These compounds provide a broad range of important physiological benefits, including anti-inflammatory and immune regulation, as well as anti-cancer properties and metabolic regulation. The properties of legumes make it possible to use them to create synbiotic food, which is a source of probiotics and prebiotics.

Role of Probiotic Bacilli in Developing Synbiotic Food: Challenges and Opportunities

The human body is inhabited by a vast diversity of probiotic microorganisms that could positively affect human physiology. Besides, prebiotic food substances may induce symbiotic relationship among probiotic species through the successful establishment of commensal microbiota, whose connections with the host are multifaceted and multidirectional. As deliberated throughout this review, prebiotic and synbiotic foods contain the capability to stimulate numerous health characteristics in host organisms through various means. Predominantly, the normal microbiota fosters the digestion of food and may boost the innate and adaptive immune system’s functionalities. Therefore, live probiotic bacteria, for instance, probiotic Bacilli obtained together with prebiotic food, can help stimulate healthiness in humans. Thus, we discuss how certain dietary fibers may preserve the probiotic efficacy by serving as the scaffold for probiotic Bacilli to colonize them through forming symbiotic interactions. The fibers can essentially promote protection by encapsulating probiotic Bacilli against various environmental and physical stresses that might kill the free-living bacterial cells. Besides, these fibers would serve as prebiotic substances that would eventually be utilized for the proliferation of probiotic cells. It is believed that applying this conceptual idea will provide a novel platform toward developing probiotic and synbiotic foods, as discussed in this review.

Nutritional and Bioactive Components of Carioca Common Bean (Phaseolus vulgaris L.) Tempeh and Yellow Soybean (Glycine max L.) Tempeh

Background:

Tempeh, a product of Indonesian origin based on fermented soybeans, is present in naturalistic diets and has been gaining popularity in other cultures and diets due to the convenience for food preparation and use, aside from the nutritional and functional quality.

Methods:

In this work, tempehs were produced from common bean, carioca grain type (CBT) aged and peeled, and in combination with yellow soybean (CBST: 50:50). Products were characterized based on nutritional quality (proximate composition, fiber, mineral, vitamin B12, energetic value), physical-chemical properties (pH, acidity, moisture, water activity), functional characteristics (antioxidant capacity), sensorial aspects (texture and color) and antinutrient content. Data from beanbased tempehs and the commercially purchased traditional soybean tempeh (ST) were statistically evaluated and the means compared by Tukey test.

Results:

Although CBT was found nutritionally inferior to ST, its contribution on protein intake was noteworthy and, unlike ST, it presented high fiber content and low caloric value. P, K, Mg, Cu and Mo levels meet daily requirements for adults. CBT showed higher antioxidant capacity by DPPH method and was significantly more soft and elastic and less sticky and gummy when compared to ST, and L, a* and b* CBT color parameters were more pronounced than ST.

Conclusion:

It can thus be concluded that tempeh based on carioca common beans can be an interesting alternative for stored grains, with good sensorial and functional properties and making an important nutritional contribution to the diet.

Lactic Fermentation as a Strategy to Improve the Nutritional and Functional Values of Pseudocereals

One of the greatest challenges is to reduce malnutrition worldwide while promoting sustainable agricultural and food systems. This is a daunting task due to the constant growth of the population and the increasing demands by consumers for functional foods with higher nutritional values. Cereal grains are the most important dietary energy source globally; wheat, rice, and maize currently provide about half of the dietary energy source of humankind. In addition, the increase of celiac patients worldwide has motivated the development of gluten-free foods using alternative flour types to wheat such as rice, corn, cassava, soybean, and pseudocereals (amaranth, quinoa, and buckwheat). Amaranth and quinoa have been cultivated since ancient times and were two of the major crops of the Pre-Colombian cultures in Latin- America. In recent years and due to their well-known high nutritional value and potential health benefits, these pseudocereals have received much attention as ideal candidates for gluten-free products. The importance of exploiting these grains for the elaboration of healthy and nutritious foods has forced food producers to develop novel adequate strategies for their processing. Fermentation is one of the most antique and economical methods of producing and preserving foods and can be easily employed for cereal processing. The nutritional and functional quality of pseudocereals can be improved by fermentation using Lactic Acid Bacteria (LAB). This review provides an overview on pseudocereal fermentation by LAB emphasizing the capacity of these bacteria to decrease antinutritional factors such as phytic acid, increase the functional value of phytochemicals such as phenolic compounds, and produce nutritional ingredients such as B-group vitamins. The numerous beneficial effects of lactic fermentation of pseudocereals can be exploited to design novel and healthier foods or grain ingredients destined to general population and especially to patients with coeliac disease.

Improvement in Cognition Following Double-Blind Randomized Micronutrient Interventions in the General Population

The impact of poor nutrition on physiological health is well understood (Costarelli et al., 2013). Less is known about the effects of diet on brain function and cognition in the general population (Ames, 2010; Parletta et al., 2013; White et al., 2017) and we are still in the early stages of understanding the role of specific nutrients to normal and pathological neuronal functioning. In the present study, the putative effect of a multivitamin/mineral or vitamin D supplement on cognitive function over an 8-week period was compared with volunteers taking vitamin C. Healthy adults (N = 60) were recruited, age range 21-59 years ( x ¯ = 39.07 years, SD = 11.46), with participants randomly allocated to conditions in a double-blind protocol. Participants also completed a 14-day food diary to gather information on micronutrient intake. The cognitive test battery included measures from the Wechsler Adult Intelligence Scale-III (WAIS-III; Wechsler et al., 2008), Wechsler Memory Scale-IV (WMS-IV; Wechsler, 2009) and Delis-Kaplan Executive Function System (D-KEFS; Delis et al., 2001), along with the Doors and People (Baddeley et al., 1994) and a serial reaction time task. Analyses showed better performance on some tasks in all groups following the intervention period, notably on measures of verbal and visual memory and visuomotor processing speed. The Multivitamin group showed significant improvements on tasks of visual strategy generation (along with the Vitamin C group), motor planning, explicit and implicit learning, and working memory. This evidence suggests that sub-optimal micronutrient intake may have a negative effect on cognition across the lifespan.

Application of Lactobacillus as Adjunct Cultures in Wheat Dough Fermentation

The purpose of this study was to evaluate the potential use of Lactobacillus from traditional Chinese sourdoughs of different regions as original adjunct cultures in the steamed bread making process. The effects of Lactobacillus on dough and steamed bread were evaluated. Some differences were obtained in the parameters of fermented dough (organic acid content, rheofermentative parameters, pH, and total titratable acidity [TTA]) and steamed bread (hardness, specific volume, organic acid content, shape, color, pH, TTA and sensory score) made with five different Lactobacillus strains (Pediococcus pentosaceus, Lactobacillus fermentum, Weissella confusa, Lactobacillus crustorum, and Pediococcus acidilactici). Steamed bread made with P. pentosaceus showed a significant increase in specific volume (from 2.19 to 2.41) and a decrease in hardness (from 3,158 g to 2,301 g). Dough leavened by L. fermentum showed significantly higher amounts of lactic acid and acetic acid than dough inoculated with W. confusa, which had values similar to those of the control. The dough fermented by P. pentosaceus exhibited the most gas production (1,811 mL), which is an important index of streamed bread quality. Our research provides a reference for making steamed bread with Lactobacillus. PRACTICAL APPLICATION: Probiotic Lactobacillus is widely used to produce fermenting foods and has been used in bread processing to improve the quality and characteristics of bread. Steamed bread is one of the most popular fermented foods in northern China. However, there is little information about the application of Lactobacillus in Chinese steamed bread. This study explored the potential use of Lactobacillus to improve the characteristics and quality of steamed bread.

Fermentation-based biotransformation of glucosinolates, phenolics and sugars in retorted broccoli puree by lactic acid bacteria

This study investigated the effect of lactic acid bacteria (LAB) fermentation on the chemical profile of autoclaved broccoli puree, using 7 broccoli-derived LAB isolates (named F1-F5, BF1 and BF2). The total concentrations of glucosinolates (glucoiberin, progoitrin and glucoraphanin) and 10 major phenolics significantly increased from trace level and 289 μg total phenolics/g dry weight (DW) respectively in autoclaved broccoli to 55 to ∼359 μg/g DW and 903 to ∼3105 μg/g DW respectively in LAB fermented broccoli puree. Differential impacts of LAB isolates on the chemical composition of autoclaved broccoli were observed, with the major differences being the significant increase in phloretic acid after fermentation by F1-F5 and an elevated glucoraphanin level in ferments by F1 and BF2. LAB fermentation is a promising way to increase the content of glucosinolates and polyphenolic compounds in broccoli, making the ferments attractive for use as functional ingredients or as a whole functional food.

In situ production of active vitamin B12 in cereal matrices using Propionibacterium freudenreichii

The in situ production of active vitamin B12 was investigated in aqueous cereal‐based matrices with three strains of food‐grade Propionibacterium freudenreichii. Matrices prepared from malted barley flour (33% w/v; BM), barley flour (6%; BF), and wheat aleurone (15%; AM) were fermented. The effect of cobalt and the lower ligand 5,6‐dimethylbenzimidazole (DMBI) or its natural precursors (riboflavin and nicotinamide) on active B12 production was evaluated. Active B12 production was confirmed by UHPLC–UV–MS analysis. A B12 content of 12–37 μg·kg⁻¹ was produced in BM; this content increased 10‐fold with cobalt and reached 940–1,480 μg·kg⁻¹ with both cobalt and DMBI. With riboflavin and nicotinamide, B12 production in cobalt‐supplemented BM increased to 712 μg·kg⁻¹. Approximately, 10 μg·kg⁻¹ was achieved in BF and AM and was increased to 80 μg·kg⁻¹ in BF and 260 μg·kg⁻¹ in AM with cobalt and DMBI. The UHPLC and microbiological assay (MBA) results agreed when both cobalt and DMBI or riboflavin and nicotinamide were supplemented. However, MBA gave ca. 20%–40% higher results in BM and AM supplemented with cobalt, indicating the presence of human inactive analogues, such as pseudovitamin B12. This study demonstrates that cereal products can be naturally fortified with active B12 to a nutritionally relevant level by fermenting with P. freudenreichii.

Improved quality of a vitamin B12-fortified ‘ready to blend’ fresh-cut mix salad with chitosan

A vitamin B12-fortified (0.25 mg L−1) chitosan (10 g L−1) coating was applied to a ready-to-blend fresh-cut salad including melon, pineapple and carrot, which was stored at 5 ℃ up to nine days. Uncoated samples were used as control while the vitamin B12 effect was compared to non-fortified chitosan-coated samples. Beverages were prepared on blending days 0, 4, 7 and 9 with subsequent storage at 5 ℃ for 0, 24 and 48 h. Physicochemical quality of fresh blended beverages was well preserved throughout storage. The chitosan coating highly reduced epiphytic microflora growth and polyphenoloxidase/peroxidase activities. No relevant variations of total phenolic contents were observed between different fresh blended beverages. However, its total antioxidant capacity reported after blending was lower as storage time of ready-to-blend samples increased. Fortified samples showed a vitamin B12 content of 8.6 µg kg−1 on processing day, ensuring 200 mL of such beverage the recommended daily intake of this vitamin. In conclusion, a ready-to-blend fruit/vegetable mix, fortified with vitamin B12, was developed with a shelf life of nine days at 5 ℃ showing the prepared beverages good quality during subsequent storage for 48 h at 5 ℃.

Food-Like Growth Conditions Support Production of Active Vitamin B12 by Propionibacterium freudenreichii 2067 without DMBI, the Lower Ligand Base, or Cobalt Supplementation

Propionibacterium freudenreichii is a traditional dairy bacterium and a producer of short chain fatty acids (propionic and acetic acids) as well as vitamin B12. In food applications, it is a promising organism for in situ fortification with B12 vitamin since it is generally recognized as safe (GRAS) and it is able to synthesize biologically active form of the vitamin. In the present study, vitamin B12 and pseudovitamin biosynthesis by P. freudenreichii was monitored by UHPLC as a function of growth in food-like conditions using a medium mimicking cheese environment, without cobalt or 5,6-dimethylbenzimidazole (DMBI) supplementation. Parallel growth experiments were performed in industrial-type medium known to support the biosynthesis of vitamin B12. The production of other key metabolites in the two media were determined by HPLC, while the global protein production was compared by gel-based proteomics to assess the effect of growth conditions on the physiological status of the strain and on the synthesis of different forms of vitamin. The results revealed distinct protein and metabolite production, which reflected the growth conditions and the potential of P. freudenreichii for synthesizing nutritionally relevant amounts of active vitamin B12 regardless of the metabolic state of the cells.

Nondairy beverage produced by controlled fermentation with potential probiotic starter cultures of lactic acid bacteria and yeast

This work aimed to develop a nondairy fermented beverage from a blend of cassava and rice based on Brazilian indigenous beverage cauim using probiotic lactic acid bacteria (LAB) and yeast. The indigenous strains Lactobacillus plantarum CCMA 0743 (from cauim) and Torulaspora delbrueckii CCMA 0235 (from tarubá), and the commercial probiotic, L. acidophilus LAC-04, were used as starter cultures in single and co-cultivations. The bacteria populations were around 8.0 log (CFU/mL) at the end of all fermentations as recommended for probiotic products. Higher residual starch contents were noted in the single LAB cultures (10.6% [w/w]) than in co-cultures (<6% [w/w]), showing that co-culture may help the digestibility. For all different assays (single and co-culture), lactic acid was the main organic acid detected (>1.6g/L) and ethanol was lower than 0.5% (w/v) consisting in a non-alcoholic beverage. The assays containing yeast showed the highest antioxidant activity (around 10% by DPPH and ABTS methods). Therefore, a nondairy fermented beverage was successfully obtained, and the co-culture of LAB and T. delbrueckii could increase the product's functional properties.

Next-generation sequencing approaches for improvement of lactic acid bacteria-fermented plant-based beverages

Plant-based beverages and milk alternatives produced from cereals and legumes have grown in popularity in recent years due to a range of consumer concerns over dairy products. These plant-based products can often have undesirable physiochemical properties related to flavour, texture, and nutrient availability and/or deficiencies. Lactic acid bacteria (LAB) fermentation offers potential remediation for many of these issues, and allows consumers to retain their perception of the resultant products as natural and additive-free. Using next-generation sequencing (NGS) or omics approaches to characterize LAB isolates to find those that will improve properties of plant-based beverages is the most direct way to product improvement. Although NGS/omics approaches have been extensively used for selection of LAB for use in the dairy industry, a comparable effort has not occurred for selecting LAB for fermenting plant raw substrates, save those used in producing wine and certain types of beer. Here we review the few and recent applications of NGS/omics to profile and improve LAB fermentation of various plant-based substrates for beverage production. We also identify specific issues in the production of various LAB fermented plant-based beverages that such NGS/omics applications have the power to resolve.

Techno-functional differentiation of two vitamin B12 producing Lactobacillus plantarum strains: an elucidation for diverse future use

An appropriate selection of Lactobacillus strain (probiotic/starter/functional) on the basis of its techno-functional characteristics is required before developing a novel fermented functional food. We compared vitamin B₁₂ (B₁₂, cobalamin) producing Lactobacillus plantarum isolates, BHM10 and BCF20, for functional (vitamin over-production, genomic insight to B₁₂ structural genes, and probiotic attributes) and technological [milks (skim and soy) fermentation and B₁₂ bio-fortification] characteristics. Addition of B₁₂ precursors (5-amonolevulinate and dimethylbenzimidazole) to cobalamin-free fermentation medium increased vitamin production in BHM10, BCF20, and DSM20016 (a positive standard) by 3.4-, 4.4-, and 3.86-folds, respectively. Three important B₁₂ structural genes were detected in L. plantarum species (strains BHM10 and BCF20) by PCR for the first time. The gene sequences were submitted to NCBI GenBank and found phylogenetically closer to respective sequences in B₁₂ producing Lactobacillus reuteri strains. During comparative probiotic testing, BCF20 showed significantly higher (p < 0.05 to p < 0.001) gastrointestinal tolerance and cell surface hydrophobicity (p < 0.05) than BHM10. Moreover, only BCF20 was found positive for BSH activity and also exhibited comparatively better antagonistic potential against potent pathogens. Conversely, high acid and bile susceptible strain BHM10 displayed significantly higher soy milk fermentation and resultant B₁₂ bio-fortification abilities during technological testing. Two B₁₂ quantification techniques, UFLC and competitive immunoassay, confirmed the in vitro and in situ bio-production of bio-available form of B₁₂ after BHM10 fermentation. Conclusively, techno-functional differentiation of two B₁₂ producing strains elucidates their diverse future use; BCF20 either for B₁₂ over-production (in vitro) or as a probiotic candidate, while BHM10 for cobalamin bio-fortification (in situ) in soy milk.

Cobalamin production by Lactobacillus coryniformis: biochemical identification of the synthetized corrinoid and genomic analysis of the biosynthetic cluster

Background

Despite the fact that most vitamins are present in a variety of foods, malnutrition, unbalanced diets or insufficient intake of foods are still the cause of vitamin deficiencies in humans in some countries. Vitamin B₁₂ (Cobalamin) is a complex compound that is only naturally produced by bacteria and archea. It has been reported that certain strains belonging to lactic acid bacteria group are capable of synthesized water-soluble vitamins such as those included in the B-group, as vitamin B₁₂. In this context, the goal of the present paper was to evaluate and characterize the production of vitamin B₁₂ in Lactobacillus coryniformis CRL 1001, a heterofermentative strain isolated from silage.

Results

Cell extract of L. coryniformis CRL 1001, isolated from silage, is able to correct the coenzyme B₁₂ requirement of Salmonella enterica serovar Typhimurium AR 2680 in minimal medium. The chemical characterization of the corrinoid-like molecule isolated from CRL 1001 cell extract using HPLC and mass spectrometry is reported. The majority of the corrinoid produced by this strain has adenine like Coα-ligand instead 5,6-dimethylbenzimidazole. Genomic studies revealed the presence of the complete machinery of the anaerobic biosynthesis pathway of coenzyme B₁₂. The detected genes encode all proteins for the corrin ring biosynthesis and for the binding of upper (β) and lower (α) ligands in one continuous stretch of the chromosome.

Conclusions

The results here described show for the first time that L. coryniformis subsp. coryniformis CRL 1001 is able to produce pseudocobalamin containing adenine instead of 5,6-dimethlbenzimidazole in the Coα-ligand. Genomic analysis allowed the identification and characterization of the complete de novo biosynthetic pathway of the corrinoid produced by the CRL 1001 strain.

Novel fermented chickpea milk with enhanced level of γ-aminobutyric acid and neuroprotective effect on PC12 cells

In this study, novel fermented chickpea milk with high γ -aminobutyric acid (GABA) content and potential neuroprotective activity was developed. Fermentation starter that can produce GABA was selected from 377 strains of lactic acid bacteria isolated from traditional Chinese fermented foods. Among the screened strains, strain M-6 showed the highest GABA-producing capacity in De Man-Rogosa and Sharp (MRS) broth and chickpea milk. M-6 was identified as Lactobacillus plantarum based on Gram staining, API carbohydrate fermentation pattern testing, and 16s rDNA sequencing. The complete gene encoding glutamate decarboxylase was cloned to confirm the presence of the gene in L. plantarum M-6. The fermentation condition was optimized by response surface methodology. Results demonstrated that L. plantarum M-6 produced the highest GABA content of 537.23 mg/L. The optimal condition included an inoculum concentration of 7%, presence of 0.2% (m/v) monosodium glutamate and 55 µ M pyridoxal-5-phosphate, incubation temperature of 39 °C and fermentation time of 48 h . GABA-enriched chickpea milk exerted protective effects on PC12 cells against MnCl2 -induced injury. GABA-enriched chickpea milk improved cell viability and markedly attenuated the release of lactate dehydrogenase compared with the impaired cells.

BluB/CobT2 fusion enzyme activity reveals mechanisms responsible for production of active form of vitamin B₁₂ by Propionibacterium freudenreichii

Background

Propionibacterium freudenreichii is a food grade bacterium that has gained attention as a producer of appreciable amounts of cobalamin, a cobamide with activity of vitamin B₁₂. Production of active form of vitamin is a prerequisite for attempts to naturally fortify foods with B₁₂ by microbial fermentation. Active vitamin B₁₂ is distinguished from the pseudovitamin by the presence of 5,6-dimethylbenzimidazole (DMBI) as the lower ligand. Genomic data indicate that P. freudenreichii possesses a fusion gene, bluB/cobT2, coding for a predicted phosphoribosyltransferase/nitroreductase, which is presumably involved in production of vitamin B₁₂. Understanding the mechanisms affecting the synthesis of different vitamin forms is useful for rational strain selection and essential for engineering of strains with improved B₁₂ production properties.

Results

Here, we investigated the activity of heterologously expressed and purified fusion enzyme BluB/CobT2. Our results show that BluB/CoBT2 is responsible for the biosynthesis of the DMBI base and its activation into α-ribazole phosphate, preparing it for attachment as the lower ligand of cobalamin. The fusion enzyme was found to be efficient in metabolite channeling and the enzymes’ inability to react with adenine, a lower ligand present in the pseudovitamin, revealed a mechanism favoring the production of the active form of the vitamin. P. freudenreichii did not produce cobalamin under strictly anaerobic conditions, confirming the requirement of oxygen for DMBI synthesis. In vivo experiments also revealed a clear preference for incorporating DMBI over adenine into cobamide under both microaerobic and anaerobic conditions.

Conclusions

The herein described BluB/CobT2 is responsible for the production and activation of DMBI. Fusing those two activities results in high pressure towards production of the true vitamin B₁₂ by efficiently activating DMBI formed within the same enzymatic complex. This indicates that BluB/CobT2 is the crucial enzyme in the B₁₂ biosynthetic pathway of P. freudenreichii. The GRAS organism status and the preference for synthesizing active vitamin form make P. freudenreichii a unique candidate for the in situ production of vitamin B₁₂ within food products.

Electronic supplementary material

The online version of this article (doi:10.1186/s12934-015-0363-9) contains supplementary material, which is available to authorized users.

Determination of microbiological and chemical properties of probiotic boza and its consumer acceptability

OBJECTIVE

The aim of research was producing boza as a probiotic product with certificated probiotic starter cultures (Lactobacillus acidophilus LA-5 and Bifidobacterium bifidum BB-12 and Saccharomyces boulardii).

METHODS

Analysis were done in boza samples taken in fermentation and storage. Probiotic and non-probiotic bacteria were enumerated with pour plate technique and yeast enumerated spread plate technique. Sugar, organic acid and Water soluble vitamin content were determined by using of HPLC. Sensory analyses were done by two different types of panels, once comprised of trained panelists and the other of consumers. Shelf life was determined according the results of sensory analysis.

RESULTS

It was determinated that S. boulardii and L acidophilius counts increased nearly 0.5 log unit during of boza fermentation. Lactic, acetic, citric, butyric and succinic acid as organic acids and thiamin, niacin, B6 and pantothenic acid as water soluble vitamin evaluated in boza samples. Shelf life of the probiotic boza determined as 12 days at +4°C fridge storage temperature.

CONCLUSION

The boza samples had a probiotic effect because it had viable microorganisms more than 10(6) cfu/ml which was defined enough for functional foods. All boza samples had lower pH value than 4.5, so it is evaluated that boza is a safety food as its low pH preventing pathogen growth.