Komagataeibacter intermedius V-05: An Acetic Acid Bacterium Isolated from Vinegar Industry, with High Capacity for Bacterial Cellulose Production in Soybean Molasses Medium.

RESEARCH BACKGROUND: Despite the great properties of bacterial cellulose, its manufacture is still limited due to difficulties in large-scale production. These problems are mainly related to low production yields and high overall costs of the conventional culture media normally used. To surpass these problems, it is necessary to identify new cheap and sustainable carbon sources. Thus, this work aims to isolate and select a high cellulose-producing Komagataeibacter strain from vinegar industry, and study its potential for bacterial cellulose synthesis in an industrial soybean co-product, known as soybean molasses, used as fermentation medium. EXPERIMENTAL APPROACH: One isolated strain was able to produce high amount of cellulose in the standard Hestrin-Schramm medium, so we tested its ability to produce this biopolymer in a soybean molasses medium. The characteristics and properties of the produced bacterial cellulose membranes were analyzed by thermogravimetric analysis, X-ray diffraction, infrared spectroscopy, water-holding capacity and rehydration ratio. Genetic analysis of the selected strain served to determine its genus and species. RESULTS AND CONCLUSIONS: An isolated strain that produced the highest amount of cellulose in Hestrin-Schramm medium (3.7 g/L) was genetically identified as Komagataeibacter intermedius V-05. This strain produced 10.0 g/L of cellulose in soybean molasses medium. Membranes from both substrates had similar chemical structure, crystallinity and thermal degradation. Soybean molasses proved to be a suitable alternative medium for biosynthesis of cellulose in comparison with the standard medium. In addition to providing higher production yield, the membranes showed great structural characteristics, similar to those obtained from standard medium. NOVELTY AND SCIENTIFIC CONTRIBUTION: In this research, we have isolated and identified a Komagataeibacter strain which exhibits a high capacity for cellulose production in soybean molasses. The isolation and selection of strains with high capacity for microbial metabolite production is important for decreasing bioprocess costs. Furthermore, as there is a necessity today to find cheaper carbon sources to obtain microbial products at a lower cost, soybean molasses represents an interesting alternative medium to produce bacterial cellulose for its industrial application.

Vinegar from Anacardium othonianum Rizzini using submerged fermentation.

BACKGROUND: Anacardium othonianum Rizzini is a native Cerrado fruit, recently described in the literature. Its use is restricted to its native region and there is a lack of studies regarding production of vinegar from the pulp. This work aims to investigate the production of A. othonianum Rizzini vinegar using submerged fermentation. RESULTS: The density, alcohol content, proximal composition, pH, color coordinates, and chromatographic profile of the volatile compounds were analyzed in the slurry, fermented juice, and vinegar produced from the corpulent parts of A. othonianum Rizz. Sensory acceptance and willingness to pay were also assessed with vinegar at 4% and 6% of total acidity. The results indicated compliance with European legislation and the presence of volatile compounds such as carbon dioxide, acetic acid, ethanol, and acetaldehyde in the analyzed vinegars. Our results indicate the potential of vinegar production from A. othonianum, with 74% and 86% willingness to pay. CONCLUSIONS: The process of transformation of the fruit pulp into new products can contribute to fruit valorization and consequent preservation of the plant in the Cerrado biome. To the best of our knowledge, this is the first report of volatile compounds and minerals in A. othonianum Rizz. slurry. Our observations can be used as a basis for future studies regarding the preparation of vinegars from this species and for investigating their application in cooking and guiding consumer perception. © 2020 Society of Chemical Industry.

Vinegar production from fruit concentrates: effect on volatile composition and antioxidant activity.

Vinegar stands as a highly appreciated fermented food product due to several functional properties and multiple applications. This work focuses on vinegar production from fruit wines derived from fruit concentrates, to attain a food product with nutritional added value. Four fruit vinegars (orange, mango, cherry and banana), were produced and characterized, with total acidities of 5.3 ± 0.3% for orange, 5.6 ± 0.2% for mango, 4.9 ± 0.4% for cherry and 5.4 ± 0.4% for banana. Acetification showed impact on aroma volatiles, mainly related to oxidative reactions. Minor volatiles associated with varietal aroma were identified, monoterpenic alcohols in orange vinegar, esters in banana vinegar, C13-norisoprenoids in cherry vinegar and lactones in mango vinegar, indicating fruit vinegars differentiated sensory quality. Total antioxidant activity analysis by FRAP, revealed fruit vinegars potential to preserve and deliver fruit functional properties. Antioxidant activity of fruit vinegars, expressed as equivalents of Fe2SO4, was of 11.0 ± 1.67 mmol L-1 for orange, 4.8 ± 0.5 mmol L-1 for mango, 18.6 ± 2.33 mmol L-1 for cherry and 3.7 ± 0.3 mmol L-1 for banana. Therefore, fruit vinegars presented antioxidant activity close to the reported for the corresponding fruit, and between 8 and 40 folds higher than the one found in commercial cider vinegar, demonstrating the high functional potential of these novel vinegar products.

Fermentation Technology and Functional Foods.

Food is an integral part of our civilization. It is a cultural phenomenon that, while having evolved, is associated with societal traditions and identity. This work analyzes studies conducted to highlight the health properties of the most common ethnic foods. Although these foods were originally created from the need to preserve perishable produce, presently, we know that the fermentation process makes them nutritionally more complete. The basis of these transformations lies in that vast range of prokaryotic and eukaryotic microorganisms that, similar to small biochemical factories, can transform the initial nutrients into metabolically more active biomolecules through fermentation. Although naturally occurring microbes work together for mutual benefit, environmental conditions enhance or inhibit their development. Starting from a selection of microorganisms naturally present on a substrate, we attempt to select the most suitable species to obtain a fermented food with the best nutritional qualities and the richest in nutraceuticals.

Bacterial cellulose production by Komagataeibacter hansenii can be improved by successive batch culture.

Bacterial cellulose (BC) is a biopolymer principally synthetized by strains of the genus Komagataeibacter. However, high costs and low production yield make large-scale application difficult. The aim of this work was to evaluate the effects of successive batch culture before fermentation on the ability to increase the capacity of bacterial cellulose biosynthesis by a low-producing strain. The Komagataeibacter hansenii strain ATCC 23,769 was initially cultivated in fermentation broth for two periods of 35 or 56 days under static conditions. At the end of each period of time, they were transferred to new broth to be cultivated again (new batch culture cycle) for 35 or 56 days and carried out in parallel with a 10-day fermentation to determine the quantity of BC produced. As a result, a greater increase was observed after the end of the second and third batch cultures of 56 days (increases of 137% and 187% in relation to the nonbatch cultured strain, respectively). The produced samples presented higher crystallinity and thermal properties but lower water holding capacity. Through this work, it was concluded that the longer the batch culture time was, the greater the increase in the capacity of cellulose biosynthesis, which also depended on the number of successive batch culture cycles carried out.

Nutritional Supplementation with Amino Acids on Bacterial Cellulose Production by Komagataeibacter intermedius: Effect Analysis and Application of Response Surface Methodology.

Bacterial cellulose (BC) is a biopolymer mainly produced by acetic acid bacteria (AAB) that has several applications in the medical, pharmaceutical, and food industries. As other living organisms, AAB require sources of chemical elements and nutrients, which are essential for their multiplication and metabolite production. So, the knowledge of the nutritional needs of microorganisms that have important industrial applications is necessary for the nutrients to be supplied in the appropriate form and amount. Considering that the choice of different nutrients as nitrogen source can result in different metabolic effects, this work aimed to verify the effects of amino acid supplementation in the culture media for BC production by an AAB strain (Komagataeibacter intermedius V-05). For this, nineteen amino acids were tested, selected, and optimized through a Plackett and Burman factorial design and central composite design to determine the optimal concentrations of each required amino acid. Membranes produced under optimal conditions were characterized in relation to chemical structure and properties by X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), infrared spectroscopy (FT-IR), and hydrophilic properties. Three amino acids had a significant positive effect and were required: aspartic acid (1.5 g L-1), phenylalanine (1.5 g L-1), and serine (3.0 g L-1). Conversely, all sulfur and positively charged amino acids had a negative effect and reduced the production yield. After optimization and validation steps, a production level of 3.02 g L-1 was achieved. Membranes produced from optimized media by this strain presented lower crystallinity index but greater thermal and hydrophilic properties than those produced from standard HS medium.

Organic production of vinegar from mango and papaya.

The study describes the transformation of mangoes of the local variety "Assabonou" and papaya solo No.8 into alcohol and then into vinegar through the process of directed fermentation. Indeed, mango and papaya juices extracted from ripe fruits contained in vials are first subjected to an alcoholic fermentation with Saccharomyces cerevisiae in anaerobic conditions and secondly to an acetic fermentation with strains of acetic acid bacteria cultivated from unpasteurized cider vinegar. To assess the quality of the vinegars produced, their profile and composition in organic acid and volatile compounds were compared to those of an unpasteurized cider vinegar from France and a vinegar produced in Côte d'Ivoire. The ethanol content for both juices is more or less high with 9.24 ± 0.04 g/L for mango and 12.68 ± 0.39 g/L for papaya. The concentration of acetic acid is the highest of the organic acids for the four vinegars ranging from 37.46 ± 4.6 g/L to 55.85 ± 9.94 g/L. The acetic acid contents of mango and papaya vinegars are close to that of unpasteurized cider vinegar from France but higher than that of vinegar produced in Côte d'Ivoire. Thus, this study allowed the production of "Assabonou" mango and papaya vinegars from two consecutive fermentations (alcoholic then acetic). This process is fast, less expensive and easily applicable. This application case could be an alternative for the processing of seasonal fruits to reduce postharvest losses.

Effective assay for olive vinegar production from olive oil mill wastewaters.

In this work, an effective and simple approach for vinegar production from olive oil press-mill wastewaters (OMW) is presented. Effects of sterilization and yeast presence on the acetic acid production were investigated. Sugar addition and inoculum of selected yeast starter have been crucial for a satisfactory acidification. In the obtained olive vinegar, the pH and total acidity were 2.92 and 5.6%, respectively. A considerable high level of ash (2%) and total phenols (3600mg/L as GAE) characterized olive vinegar, in comparison with samples of apple, wine and balsamic commercial vinegars. Moreover, a high presence of hydroxytyrosol (1019mg/L) was obtained. This abundant presence of antioxidants makes olive vinegar a promising nutraceutical and environmentally-friendly product, based upon a waste material such as OMW.

Metabolite profiling and volatiles of pineapple wine and vinegar obtained from pineapple waste.

Vinegar is an inexpensive commodity, and economic considerations require that a relatively low-cost raw material be used for its production. An investigation into the use of a new, alternative substrate - pineapple waste - is described. This approach enables the utilization of the pineapple's (Ananas comosus) peels and core, which are usually discarded during the processing or consumption of the fruit. Using physical and enzymatic treatments, the waste was saccharified, and the resulting substrate was fermented with Saccharomyces cerevisiae for 7-10days under aerobic conditions at 25°C. This resulted in an alcohol yield of approximately 7%. The alcoholic medium was then used as a seed broth for acetic fermentation using Acetobacter aceti as the inoculum for approximately 30days at 32°C to obtain 5% acetic acid. Samples were analyzed at the beginning and end of the acetification cycle to assess the volatile and fixed compounds by GC-MS and UHPLC-QTOF-MS. The metabolomic analysis indicated that l-lysine, mellein, and gallic acid were significantly more concentrated in the pineapple vinegar than in the original wine. Higher alcohols, aldehydes, and ketones characterized the aroma of the final pineapple vinegar, whilst off-flavors were significantly reduced relative to the initial wine. This study is the first to highlight the metabolite profile of fruit vinegar with a slight floral aroma profile derived from pineapple waste. The potential to efficiently reduce the post-harvest losses of pineapple fruits by re-using them for products with added food values is also demonstrated.