Optimization Of Fermentation Process Research Articles

Technological features of fermented beverages production using kombucha

Kombucha is a beverage made by fermenting sweetened brewed tea (substrate) by symbiotic culture of yeast and bacteria. Numerous researches on optimization of fermentation process, determination of the influence of technological factors on physical and chemical properties, formation of taste and flavor profile of the beverages, prevention of industrial product risks are due to the growing popularity of kombucha in Europe and the USA. Technological features of kombucha production are to optimize conditions for the growth of symbiotic culture and substrate fermentation. The duration of the process depends on the composition of the substrate, the ratio of tea mushroom and substrate, temperature, size and shape of fermentation vessel. The aim of the work was to generalize the results of studying the technological features of the production of fermented kombucha type beverages and to identify the factors that affect the chemical composition and safety of the finished beverages. Material and methods. Analytical research was carried out on the main databases for the keyword "kombucha". The criteria for inclusion of articles in the analysis were research articles with open access and presenting detailed technology of kombucha. Results. The technology of kombucha production is based on fermentation of the substrate and obtaining the base of the beverage with high content of organic acids, mainly acetic acid. In order to ensure microbiological safety the acetic acid concentration in the beverage base must be at least 1.2%. The high organic acid content necessitates the use of only glass or stainless steel fermentation equipment approved for food contact. The fermentation temperature ranges from 18 to 32 °C. The fermentation process is monitored according to basic criteria: temperature, pH value, acidity, acetic acid content, ethyl alcohol content, and residual sugar content. Kombucha production process is connected with microbiological, chemical and physical risks which could appear in case of using low quality raw materials, equipment and consumer packaging made of materials which do not correspond to sanitary norms, violating technological regimes, storage conditions of raw materials and ready production. To prevent hazards affecting the quality and safety of the finished product, it is necessary to control the technological process at all stages of production. Conclusion. Following sanitary-hygienic norms and technological regimes allows producing kombucha with a balanced taste and aroma, which meets the safety requirements for fermented beverages.

Optimization of Agave cupreata juice fermentation process for mezcal production using statistical experimental design

Optimization of Agave cupreata juice fermentation process for mezcal production using statistical experimental design

Optimization of Small Peptide Feed from Milk Thistle Residue by Synergistic Fermentation of Multiple Strains and Proteases

In order to improve the utilization rate of the milk thistle residue, this study used the synergistic fermentation of multiple strains and proteases to increase the small peptide content of the fermented feed produced by the milk thistle residue. Taking the small peptide content of the milk thistle residue fermented feed as an indicator, the optimal fermentation process was obtained by single-factor optimization experiments and the response surface methodology. The optimal fermentation process was as follows: fermentation time of 7 days, inoculum size of 15%, inoculation ratio of aerobic strains: anaerobic strains = 1: 2, solid-state fermentation water content of 66%, fermentation temperature of 36℃, and amount of protease was 0.25% acid protease+0.25% bromelain. Under the above process, the small peptide content of the fermented feed from milk thistle residue was greatly improved to 57.86%. These results inferred that the added proteases were beneficial to the growth of fermentative microorganisms, the secretion of protease and the increase of the small peptide content.

Advances in the biosynthesis of pentostatin

Pentostatin is a nucleoside antibiotics with a strong inhibitory effect on adenosine deaminase, and is widely used in the clinical treatment of malignant tumors. However, the high cost hampers its application. In the past 10 years, the biosynthesis of pentostatin were focused on strain breeding, optimization of medium composition and fermentation process. To date, there are no reviews summarizing the elucidated biosynthetic mechanism of pentostatin. This review starts by introducing the various chemical route for production of pentostatin, followed by summarizing the mechanisms of pentostatin biosynthesis in different microorganisms. Finally, challenges for biosynthesis of pentostatin were discussed, and strategies for regulating and improving the microbial synthesis of pentostatin were proposed.

Screening and Identification of Yeasts from Fruits and Their Coculture for Cider Production

Coculturing non-Saccharomyces yeasts with Saccharomyces cerevisiae could enrich the aromatic complexity of alcoholic beverages during cider brewing. Therefore, the present study performed rapid strain screening via selective culture medium and aroma analysis and adopted a response surface methodology to optimize fermentation conditions to produce 2-phenylethyl acetate (PEA), which presents a rose and honey scent. The effects of coculturing yeasts on cider quality were evaluated through hedonic sensory analysis and the check-all-that-apply (CATA) method. Hanseniaspora vineae P5 and S. cerevisiae P1 produced ciders with high levels of PEA and 2-phenylethanol, respectively. The optimal fermentation process consisted of sequential inoculation with a 31 h delay between inoculations, followed by fermentation for 14.5 d at 18.7 °C, yielding 17.41 ± 0.51 mg/L of PEA, which was 4.6-fold higher than that obtained through the unoptimized fermentation process. Additionally, the CATA results revealed that the cider produced through coculturing was associated with descriptors such as “smooth taste”, “honey”, “pineapple”, and “fruity”, which can be attributed to the high ethyl acetate and PEA levels in the cider.

Ultrasound assisted in situ separation of sophorolipids in multi-phase fermentation system to achieve efficient production by Candida bombicola.

Sophorolipids (SLs) are regarded as one of the most promising biosurfactants. However, high production costs are the main obstacle to extended SLs application. Semi-continuous fermentation, which is based on in situ separation, is a promising technology for achieving high SLs productivity. In this study, the sedimentation mechanism of SLs was analyzed. The formation of a hydrophobic mixture of SLs and rapeseed oil was a key factor in sedimentation. And the hydrophobicity and density of the mixture determined SLs sedimentation rate. On this basis, ultrasonic enhanced sedimentation technology (UEST) was introduced, by which the sedimentation rates were increased by 46.9%-485.4% with different ratio of rapeseed oil to SLs. UEST-assisted real-time in situ separation and semi-continuous fermentation were performed. SLs productivity and yield were 2.15gL-1 h-1 and 0.58gg-1 , respectively, simultaneously the loss ratio of cells, glucose, and rapeseed oil were significantly reduced. This study provides a new horizon for optimization of the SLs fermentation process.

Rhodotorula toruloides: an ideal microbial cell factory to produce oleochemicals, carotenoids, and other products.

Requirement of clean energy sources urges us to find substitutes for fossil fuels. Microorganisms provide an option to produce feedstock for biofuel production by utilizing inexpensive, renewable biomass. Rhodotorula toruloides (Rhodosporidium toruloides), a non-conventional oleaginous yeast, can accumulate intracellular lipids (single cell oil, SCO) more than 70% of its cell dry weight. At present, the SCO-based biodiesel is not a price-competitive fuel to the petroleum diesel. Many efforts are made to cut the cost of SCO by strengthening the performance of genetically modified R. toruloides strains and by valorization of low-cost biomass, including crude glycerol, lignocellulosic hydrolysates, food and agro waste, wastewater, and volatile fatty acids. Besides, optimization of fermentation and SCO recovery processes are carefully studied as well. Recently, new R. toruloides strains are developed via metabolic engineering and synthetic biology methods to produce value-added chemicals, such as sesquiterpenes, fatty acid esters, fatty alcohols, carotenoids, and building block chemicals. This review summarizes recent advances in the main aspects of R. toruloides studies, namely, construction of strains with new traits, valorization of low-cost biomass, process detection and optimization, and product recovery. In general, R. toruloides is a promising microbial cell factory for production of biochemicals.

Multivariate batch to batch optimisation of fermentation processes to improve productivity

Increasing the productivity of batch processes presents a complex challenge, with difficulties resulting from, amongst other things, the time-varying and non-linear characteristics that such processes exhibit. This paper presents an innovative optimisation technique which utilises a data-driven Gaussian process regression model, built on time-varying and non-linear historical process data, to iteratively increase batch productivity from one cycle to the next. Specifically, productivity is increased by making appropriate adjustments to batch cycle time and the trajectory of a manipulated variable. The capabilities of the proposed method are demonstrated using two benchmark fermentation simulations, Penicillin production (Pensim) and Saccharomyces Cerevisiae, where it is shown to achieve increases in productivity of between 60% and 97% compared with what was achieved using ‘golden batch’ conditions.

Nematicidal Activity of Cyclopiazonic Acid Derived From Penicillium commune Against Root-Knot Nematodes and Optimization of the Culture Fermentation Process.

Among 200 fungal strains isolated from the soil, only one culture filtrate of Aspergillus flavus JCK-4087 showed strong nematicidal activity against Meloidogyne incognita. The nematicidal metabolite isolated from the culture filtrate of JCK-4087 was identified as cyclopiazonic acid (CPA). Because JCK-4087 also produced aflatoxins, six strains of Penicillium commune, which have been reported to be CPA producers, were obtained from the bank and then tested for their CPA productivity. CPA was isolated from the culture filtrate of P. commune KACC 45973. CPA killed the second-stage juveniles of M. incognita, M. hapla, and M. arearia with EC50–3 days 4.50, 18.82, and 60.51 μg mL–1, respectively. CPA also significantly inhibited egg hatch of M. incognita and M. hapla after a total of 28 days of treatment with the concentrations > 25 μg mL–1. The enhancement of CPA production by P. commune KACC 45973 was explored using an optimized medium based on Plackett–Burman design (PBD) and central composite design (CCD). The highest CPA production (381.48 μg mL–1) was obtained from the optimized medium, exhibiting an increase of 7.88 times when compared with that from potato dextrose broth culture. Application of the wettable power-type formulation of the ethyl acetate extract of the culture filtrate of KACC 45973 reduced gall formation and nematode populations in tomato roots and soils under greenhouse conditions. These results suggest that CPA produced by P. commune KACC 45973 can be used as either a biochemical nematicide or a lead molecule for developing chemical nematicides to control root-knot nematodes.

Biotechnological Approaches to Lowering the Ethanol Yield during Wine Fermentation.

One of the most prominent consequences of global climate warming for the wine industry is a clear increase of the sugar content in grapes, and thus the alcohol level in wines. Among the several approaches to address this important issue, this review focuses on biotechnological solutions, mostly relying on the selection and improvement of wine yeast strains for reduced ethanol yields. Other possibilities are also presented. Researchers are resorting to both S. cerevisiae and alternative wine yeast species for the lowering of alcohol yields. In addition to the use of selected strains under more or less standard fermentation conditions, aerobic fermentation is increasingly being explored for this purpose. Genetic improvement is also playing a role in the development of biotechnological tools to counter the increase in the wine alcohol levels. The use of recombinant wine yeasts is restricted to research, but its contribution to the advancement of the field is still relevant. Furthermore, genetic improvement by non-GMO approaches is providing some interesting results, and will probably result in the development of commercial yeast strains with a lower alcohol yield in the near future. The optimization of fermentation processes using natural isolates is, anyway, the most probable source of advancement in the short term for the production of wines with lower alcohol contents.

Study on synergistic fermentation of bean dregs and soybean meal by multiple strains and proteases

This study was conducted to obtain the optimal fermentation process to improve the nutritional value of bean dregs (BD) and soybean meal (SBM) using single-factor experiments and response surface methodology with small peptide content as the index. The optimal fermentation process was as follows: Bacillus subtilis was selected for aerobic fermentation for 12 h, Saccharomyces cerevisiae + Lactobacillus plantarum + Lactobacillus rhamnosus was selected for anaerobic fermentation, ratio of BD and SBM = 1:1, 0.65% acid protease +0.65% papain, 15% wheat middlings, 5% inoculum size, 34 °C fermentation temperature, and 11 d fermentation time. Following fermentation, the small peptide content increased from 7.35% to 39.58%. The free amino acid content and the organic acid content increased from 2.34 mg/g to 41.39 mg/g and 28.76 mg/g to 158.61 mg/g, respectively. The added proteases greatly improved the overall protease activity of the fermentation medium, promoted the fermenting microorganism growth, amylase secretion, and reducing sugar metabolism, increased the organic acid content, made the pH lower, and improved the fermentation efficiency and the quality of fermented BD and SBM.

Optimization of Fermentation Process for Improving Soy Isoflavones Aglycone Content in Bean Dregs by Lactobacillus plantarum PL70a

Aglycone-type soy isoflavones have higher biological activity than glycoside-type soy isoflavones. Bean dregs are rich in glycoside-type soy isoflavones. In order to improve the biological activity of soy isoflavones in bean dregs, the Lactobacillus plantarum PL70a was screened and the fermentation process of converting glycoside-type soy isoflavones into aglycone-type in bean dregs was optimized by single-factor experiments and the response surface methodology. The optimal fermentation process was as follows: (NH4)2SO4 was added in an amount of 0.17%, glucoamylase was added in an amount of 0.87%, inoculation amount was 17%, sucrose was added in an amount of 1.3%, and fermentation time was 3 days. Under this process, the content of aglycone-type soy isoflavones in bean dregs significantly increased. Trypsin inhibitors and antigen proteins were almost removed. The fermentation process provides a good reference for the low-cost processing of high-quality soy isoflavone aglycone food.

Optimization of Fermentation Process and Evaluation of Quality and Flavor of Quinoa Yogurt Produced by Mixed Lactic Acid Bacteria

In this study, Streptococcus thermophilus 6063, Lactobacillus bulgaricus 6064 and Bifidobacterium animalis B15 were selected to ferment quinoa yogurt, and the puffed quinoa powder and milk were used as raw materials. Fermentation process was optimized by orthogonal experiment on the basis of single-factor experiments. And the effects of puffed quinoa powder on quality and flavor of yogurt were also evaluated. Results indicated that the optimal fermentation conditions were as follows: Streptococcus thermophilus: Lactobacillus bulgaricus: Bifidobacterium animalis=2:1:2, inoculation amount 2%(v/v), quinoa powder 5%(w/v) and fermentation temperature 41 ℃. Under these conditions, quinoa yogurt had good flavor, and the total viable number of lactic acid bacteria reached 109 CFU/mL. From the beginning of fermentation to the end of storage for 21 days, the titratable acidity of quinoa yogurt was always higher than that of plain yogurt, but the total number of viable lactic acid bacteria was opposite trend. Compared with plain yogurt, the contents of protein, polyphenols and flavonoids in quinoa yogurt increased respectively by 88.67%, 166.67%, and 284.62%. The contents of lactic acid, formic acid, acetic acid and pyruvate in quinoa yogurt were 5.80, 1.42, 0.11 and 0.01 mg/g, respectively. 74 kinds of volatile substances were detected in quinoa yogurt by GC-MS. Compared with pure yogurt, 30 kinds of new volatile substances were discovered. The research results would provide a technology support for further research and new product development of quinoa yogurt, promoting the application and development of quinoa.

Optimasi Proses Fermentasi Semi Padat Onggok Singkong Menggunakan Metode Response Surface Methodology (RSM)

The application of semi-solid fermentation has been able to increase the potential for using cassava pulp, an underused biomass from starch processing (tapioca), as foodstuffs which are reflected in an increase in protein content up to 7.07% and a decrease in cyanide content to less than 10 mg/kg (8.78 mg/kg). Further process optimization is required if the cassava pulp fermentation process is to be carried out on an industrial scale. This research was aimed to obtain the optimal fermentation process parameters to produce cassava pulp flour with optimal characteristics as foodstuffs. Optimization of the fermentation process was carried out using the Response Surface Methodology (RSM) with the Central Composite Design model. The optimization results using numerical methods show that the optimal characteristics of fermented cassava pulp flour is obtained in the process parameters: starter concentration 1.58-1.65%, ammonium sulphate concentration 1.00%, and fermentation time 75.01-82.53 hours. The optimal process parameters will produce fermented cassava pulp flour with a protein content of 6.40-6.60%, cyanide content of 7.24-7.61 mg/kg, starch content of 58.14-58.37%, dietary fiber content of 15.83-16.65% and an odour score of 4.50-4.53 (maximum score of 5, like very much) which is very potential to be used as foodstuffs.

Biological tailoring of novel sophorolipid molecules and their derivatives

AbstractA sophorolipid (SL) is a kind of glycolipid surfactant that has been much studied due to its excellent surface activity and physiological properties. However, the mixed structure of SLs and expensive separation costs have limited their application in advanced industries. Developing a tailored strategy to produce targeted SLs, with specific physicochemical properties, for direct application in various industries like agriculture, cleaning, and medicine, has become one of the main objectives of SL biological production. In this review, different characteristics of various SLs with various structures are classified in detail. The classification corresponds to their specific applications in different industries. Microorganisms for the production of specific SLs are also summarized, with emphasis on the metabolism pathways and regulation mechanisms. Strategies applied for SL biological tailoring, including selection of fermenting substrates, fermentation process optimization, metabolic engineering and downstream separation, are comprehensively reviewed. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd

Optimum Design of N Continuous Stirred-Tank Bioreactors in Series for Fermentation Processes Based on Simultaneous Substrate and Product Inhibition

Optimization of the continuous fermentation process is important for increasing efficiency and decreasing cost, especially for complicated biochemical processes described by substrate and product inhibition. The optimum design (minimum volume) of CSTRs in series assuming substrate and product inhibition was determined in this study. The effect of operating parameters on the optimum design was investigated. The optimum substrate concentration in the feed to the first reactor was determined for N reactors in series. The nonlinear, constrained optimization problem was solved using the MATLAB function “fmincon”. It was found that the optimum design is more beneficial at high substrate conversion and at a medium level of feed substrate concentration. The best number of reactors is two to three for optimum arrangements and two for equal-size arrangements. The presence of biomass in the feed to the first reactor reduces the reactor volume, while the presence of product in the feed slightly increases the required total volume. The percentage reduction in the total volume using the optimum design compared to equal-volume design (R%) was determined as a function of substrate conversion and substrate concentration in the feed to the first reactor. The obtained R% values agree with experimental data available in the literature for ethanol fermentation.

Current advances in microbial production of 1,3‐propanediol

Abstract1,3‐Propanediol (1,3‐PDO), an important chemical raw material, has attracted much attention due to its wide use as a monomer of biodegradable polyester materials. Production of 1,3‐PDO from renewable resources, through microbial fermentation, has the advantage of requiring only mild conditions. The process also demonstrates industrial safety and is environmentally friendly. In this review, we have summarized and commented on current progress in screening and breeding strains for 1,3‐PDO production, especially from glycerol or glucose. Advanced strategies, including metabolic engineering, fermentation process optimization, and construction of a microbial consortium system, are introduced and discussed. Current challenges and prospects for more efficient and economical bio‐based 1,3‐PDO production are examined in the context of its industrial application. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd

Fermentation Strategies to Improve Soil Bio-Inoculant Production and Quality.

The application of plant beneficial microorganisms has been widely accepted as an efficient alternative to chemical fertilizers and pesticides. Isolation and selection of efficient microorganisms, their characterization and testing in soil-plant systems are well studied. However, the production stage and formulation of the final products are not in the focus of the research, which affects the achievement of stable and consistent results in the field. Recent analysis of the field of plant beneficial microorganisms suggests a more integrated view on soil inoculants with a special emphasis on the inoculant production process, including fermentation, formulation, processes, and additives. This mini-review describes the different groups of fermentation processes and their characteristics, bearing in mind different factors, both nutritional and operational, which affect the biomass/spores yield and microbial metabolite activity. The characteristics of the final products of fermentation process optimization strategies determine further steps of development of the microbial inoculants. Submerged liquid and solid-state fermentation processes, fed-batch operations, immobilized cell systems, and production of arbuscular mycorrhiza are presented and their advantages and disadvantages are discussed. Recommendations for further development of the fermentation strategies for biofertilizer production are also considered.

Optimization of Fermentation Process of Pomegranate Peel and Schisandra Chinensis and the Biological Activities of Fermentation Broth: Antioxidant Activity and Protective Effect Against H2O2-induced Oxidative Damage in HaCaT Cells.

In this study, the lactobacillus fermentation process of pomegranate (Punica granatum L.) peel and Schisandra chinensis (Turcz.) Baill (PP&SC) was optimized by using the response surface method (RSM) coupled with a Box-Behnken design. The optimum fermentation condition with the maximal yield of ellagic acid (99.49 ± 0.47 mg/g) was as follows: 1:1 (w:w) ratio of pomegranate peel to Schisandra chinensis, 1% (v:v) of strains with a 1:1 (v:v) ratio of Lactobacillus Plantarum to Streptococcus Thermophilus, a 37 °C fermentation temperature, 33 h of fermentation time, 1:20 (g:mL) of a solid–liquid ratio and 3 g/100 mL of a glucose dosage. Under these conditions, the achieved fermentation broth (FB) showed stronger free radical scavenging abilities than the water extract (WE) against the ABTS+, DPPH, OH− and O2− radicals. The cytotoxicity and the protective effect of FB on the intracellular ROS level in HaCaT cells were further detected by the Cell Counting Kit-8 (CCK-8) assay. The results showed that FB had no significant cytotoxicity toward HaCaT cells when its content was no more than 8 mg/mL. The FB with a concentration of 8 mg/mL had a good protective effect against oxidative damage, which can effectively reduce the ROS level to 125.94% ± 13.46% (p < 0.001) compared with 294.49% ± 11.54% of the control group in H2O2-damaged HaCaT cells. The outstanding antioxidant ability and protective effect against H2O2-induced oxidative damage in HaCaT cells promote the potential for the FB of PP&SC as a functional raw material of cosmetics.

Analysis of methods for quantifying yeast cell concentration in complex lignocellulosic fermentation processes

Cell mass and viability are tightly linked to the productivity of fermentation processes. In 2nd generation lignocellulose-based media quantitative measurement of cell concentration is challenging because of particles, auto-fluorescence, and intrinsic colour and turbidity of the media. We systematically evaluated several methods for quantifying total and viable yeast cell concentrations to validate their use in lignocellulosic media. Several automated cell counting systems and stain-based viability tests had very limited applicability in such samples. In contrast, manual cell enumeration in a hemocytometer, plating and enumeration of colony forming units, qPCR, and in situ dielectric spectroscopy were further investigated. Parameter optimization to measurements in synthetic lignocellulosic media, which mimicked typical lignocellulosic fermentation conditions, resulted in statistically significant calibration models with good predictive capacity for these four methods. Manual enumeration of cells in a hemocytometer and of CFU were further validated for quantitative assessment of cell numbers in simultaneous saccharification and fermentation experiments on steam-exploded wheat straw. Furthermore, quantitative correlations could be established between these variables and in situ permittivity. In contrast, qPCR quantification suffered from inconsistent DNA extraction from the lignocellulosic slurries. Development of reliable and validated cell quantification methods and understanding their strengths and limitations in lignocellulosic contexts, will enable further development, optimization, and control of lignocellulose-based fermentation processes.