Optimization Of Fermentation Process Research Articles

Isolation, functional evaluation, and fermentation process optimization of probiotic Bacillus coagulans.

Bacillus coagulans is a probiotic agent widely used in various industries. In this study, we isolated a novel strain of B. coagulans, X26, from soil and characterized its properties. X26 exhibited superior enzyme, acid, and biomass yields when compared with other bacterial probiotics and an antibiotic. Moreover, X26 significantly improved the body weight of rats, highlighting its potential for industrial development as a supplement for animals. To optimize the fermentation process of this bacterium, we adopted the response surface design. When X26 was cultured in a medium with 16.5 g/L maltose, 25.00 g/L yeast extract, and 3.5 g/L K2HPO4, the optimal yield was predicted to be 5.1 × 109 CFU/mL. Consistent with the prediction, the yield of X26 in a 500-mL flask culture was (5.12 ± 0.01) × 109 CFU/mL, and in a 30-L fermenter was (5.11 ± 0.02) × 109 CFU/mL, accounting for a 9.9-fold higher field than that with a basal medium before optimization. We further optimized the fermentation process in the 30-L and a 10-T fermenter, generating yields of (7.8 ± 0.2) × 109 CFU/mL (spore rate: 96.54%) and (8.7 ± 0.1) × 109 CFU/mL (spore rate: 97.93%), respectively. These yields and spore rates were achieved at 45-55°C, the typical fermentation temperature of B. coagulans. Our findings indicate that B. coagulans X26 is a promising probiotic with considerable potential for cost-effective industrial fermentation.

Visual Tools for Food Safety Assessment of Biotechnological Products

Food biotechnology, a revolutionary discipline, has transformed the way we produce, process and consume our food. It has enabled the development of new methods of crop genetic improvement, the creation of functional foods with health benefits, and the optimization of fermentation and food production processes. It has also provided innovative solutions to address the global challenges of food security and sustainability, while opening up new possibilities for nutrition and human health.

A microbial flora with superior pollutant removal efficiency and its fermentation process optimization

Microbial flora plays an important role in microorganism-enhanced technology. The pollutant degradation ability and viable counts of these agents are crucial to guarantee their practical application. In this study, an efficient pollutant-degrading microbial flora was screened, its medium components and culture conditions were optimized, and its effect was verified in zeolite trickling filter towers. After a 24 h culture under the optimal conditions, the viable count reached 4.76 × 109 cfu/mL, with the degradation rates of ammonia nitrogen (NH4+-N), nitrate nitrogen (NO3−-N), total nitrogen (TN), total phosphorus (TP), and chemical oxygen demand (COD) increased to 93.5%, 100%, 68.3%, 32.6%, and 85%, respectively. After optimizing the feeding strategy, the concentration of viable bacteria reached 5.80 × 109 cfu/mL. In the application effect verification experiment, the degradation rates of NH4+-N, TN, TP, and COD in the experimental group reached 96.69%, 75.18%, 73.82%, and 90.83%, respectively, showing a significant improvement compared to the results of the control group. The main components in the control group were Dokdonella, Brevundimonas, Alishewanella, Rhodobacter, Pseudoxanthomonas, and Thauera, whereas those in the experimental group were Dokdonella, Proteocatella, Rhodobacter, Dechlomonas, and Nitrospira. Proteocatella, Dechlomonas, and Nitrosra, which were unique to the experimental group, are common bacteria used for nitrogen and phosphorus removal. This explains the difference in the sewage treatment capacity between the two groups. This study provides an alternative sewage treatment microbial flora with a reasonable production cost and high degradation efficiency for NH4+-N, TN, TP, and COD.

Enhanced production of L-serine in Escherichia coli by fermentation process optimization and transcriptome sequencing

In this study, the performance of Escherichia coli fermentation for L-serine production was improved by fermentation process optimization and transcriptomic analysis. The induction point, induction temperature, dissolved oxygen level and nitrogen source addition in the fed batch fermentation were studied separately to determine the optimal fermentation process. And transcriptome sequencing was applied to the fermentation process to reveal the key metabolic pathways affecting L-serine production. The results showed that the highest titer of L-serine reached 45.66 g/L with a yield of 0.39 g/g when the induction point, induction temperature, dissolved oxygen level and nitrogen source addition were OD600 = 15, 39 ℃, 40% and 10%, respectively. Transcriptome sequencing results showed that cysteine and methionine metabolism were closely related to L-serine synthesis, and the addition of L-cysteine to the medium promoted cell growth and sustained accumulation of L-serine.

Enhancing Acetic Acid Production in In Vitro Rumen Cultures by Addition of a Homoacetogenic Consortia from a Kangaroo: Unravelling the Impact of Inhibition of Methanogens and Effect of Almond Biochar on Rumen Fermentations

A homoacetogenic consortium was cultivated from feces from a nursing joey red kangaroo and inoculated into an in vitro ruminal culture. The in vitro ruminal culture was treated with methanogenic inhibitor 2-bromoethanesulfonate (BES), followed by two different homoacetogenic inoculation strategies. Initial observations showed inhibitory effects of BES, with stabilization of the acetic acid concentrations without any increase in concentration, even with the homoacetogenic inoculation. When homoacetogenic bacterial culture was added after the BES addition had ceased, acetic acid production was increased 2.5-fold. Next-generation sequencing showed an increased population of Bacteroidetes after inoculation with the homoacetogenic consortia, along with a slight decrease in diversity. An Almond Shell biochar (AS) addition resulted in a 28% increase in acetic acid concentration if tested directly on the homoacetogenic kangaroo consortia. However, when applied to the rumen culture, it did not enhance acetate production but further promoted other reductive pathways such as methanogenesis and propiogenesis, resulting in increased concentrations of methane and propionic acid, respectively. These findings demonstrate that bioaugmentation with homoacetogenic bacteria can improve acetic acid production of an in vitro rumen culture when methanogenesis has been eliminated. Such advancements can potentially contribute to the optimization of rumen fermentation processes and may have practical implications for improved livestock feed efficiency and methane mitigation strategies.

Optimization of the Ginkgo Wine Fermentation Process and Influence of Fermentation Starter Types on the Brewing Flavor

Ginkgo biloba seed (GBS) contains rich nutrients, such as starch, protein, oil, and trace components, such as flavonoids and terpene lactones. Due to its high protein content, it can be used as a raw material for fermentation and brewing. In this study, GBS was selected as the object of a fermentation process optimization test. Six kinds of fermentation starter were selected to brew ginkgo wine. The results showed that different fermentation starters have significant impacts on the composition of the wine. The yeast group had higher total sugar content and comprehensive evaluation scores than the Jiuqu group, while the total acid and total free amino acid contents showed the opposite result. The total flavonoid and total terpene lactone contents of the yeast group were 21.0% and 12.8% higher than those of the Jiuqu group, respectively. However, the 4′-O-methylpyridoxine (MPN) and 4′-O-methylpyridoxine-5′-glucoside (MPNG) contents of the yeast group were also 12.6% and 2.3% higher than those of the Jiuqu group, respectively. The common volatile components in the two groups of samples were isoamyl alcohol, phenethyl alcohol, ethyl octanoate, and phenethyl acetate. The antioxidant capacity of ginkgo wine fermented by yeast was significantly higher than that of the Jiuqu group sample.

Multi-omics study of sulfur metabolism affecting functional microbial community succession during aerobic solid-state fermentation

Microbial-mediated sulfur metabolism is closely related to carbon and nitrogen metabolism in natural biological systems. In this study, the effects of sulfur metabolism on microbial communities and functional enzyme succession were investigated based on integrated multi-omics by adding sulfur-containing compounds to aerobic fermentation systems. Sulfur powder was oxidized to S2O32- and subsequently to SO42- by the microbial sulfur-oxidizing system, which lowered the pH to 7.5 on day 7. The decrease in pH resulted in Planifilum (secreted S8, M17 and M32 proteases) losing its competitive advantage, whereas Novibacillus (secreted M14 and M19 metalloproteases) became dominant. Structural proteomics indicated that the surface of Novibacillus proteases has more negatively charged amino acid residues that help maintain protein stability at low pH. These findings aid understanding of the effects of sulfur metabolism on fermentation and the mechanism of microbial adaptation after pH reduction, providing new perspectives on the optimization of fermentation processes.

Optimization of Fermentation Process for Apricot Vinegar

To study the optimal fermentation conditions of Prunus armeniaca L. (apricot), single factor experiments and orthogonal experiments were implemented. The experimental results demonstrate that the optimum alcoholic fermentation conditions are: sugar degree a 9%, inoculation quantity of yeast at 0.7%, fermentation temperature at 30 ºC. The alcohol degree could reach 7.56%; the optimum acetic fermentation conditions are: alcohol degree at 7%, inoculation quantity of acetic acid bacillus at 0.8%, fermentation temperature at 32 ºC, fermentation time at 7 days, and the total acid content could be obtained as 6.78 g/100 mL. Under such conditions, the fruit vinegar has rich Prunus armeniaca L. flavor and pure taste.

Research progress on the fibrinolytic enzymes produced from traditional fermented foods.

Cardiovascular diseases (CVDs) are a global health problem and leading cause of death worldwide. Thrombus formation, one of the CVDs, is essentially the formation of fibrin clots. The existing thrombolytic agents have the disadvantages of high price, short half-life, and high bleeding risk; hence, there is an urgent need to find the alternative thrombolytic agents. In recent years, traditional fermented foods have been widely investigated for their outstanding effects in the prevention and treatment of thrombus formation. In this review, we have focused on fibrinolytic enzymes produced by microorganisms during the fermentation of traditional fermented foods and their potential use for treating CVDs. First, we discussed about the sources of fibrinolytic enzymes and microbial strains that produce those enzymes followed by the optimization of fermentation process, purification, and physicochemical properties of fibrinolytic enzymes. Finally, we have summarized the thrombolytic effects of fibrinolytic enzymes in humans and mice. Fibrinolytic enzymes produced by microorganisms during the fermentation of traditional fermented foods not only lyse thrombi but also acts as anti-atherosclerotic, anti-hyperlipidemia, and neuroprotection agents. Therefore, fibrinolytic enzymes from traditional fermented foods have great potential for the prevention and treatment of CVDs.

High-titer production of staurosporine by heterologous expression and process optimization.

Staurosporine is the most well-known member of the indolocarbazole alkaloid family; it can induce apoptosis of many types of cells as a strong protein kinase inhibitor, and is used as an important lead compound for the synthesis of the antitumor drugs. However, the low fermentation level of the native producer remains the bottleneck of staurosporine production. Herein, integration of multi-copy biosynthetic gene cluster (BGC) in well characterized heterologous host and optimization of the fermentation process were performed to enable high-level production of staurosporine. First, the 22.5kb staurosporine BGC was captured by CRISPR/Cas9-mediated TAR (transformation-associated recombination) from the native producer (145mg/L), and then introduced into three heterologous hosts Streptomyces avermitilis (ATCC 31267), Streptomyces lividans TK24 and Streptomyces albus J1074 to evaluate the staurosporine production capacity. The highest yield was achieved in S. albus J1074 (750mg/L), which was used for further production improvement. Next, we integrated two additional staurosporine BGCs into the chromosome of strain S-STA via two different attB sites (vwb and TG1), leading to a double increase in the production of staurosporine. And finally, optimization of fermentation process by controlling the pH and glucose feeding could improve the yield of staurosporine to 4568mg/L, which was approximately 30-fold higher than that of the native producer. This is the highest yield ever reported, paving the way for the industrial production of staurosporine. KEYPOINTS: • Streptomyces albus J1074 was the most suitable heterologous host to express the biosynthetic gene cluster of staurosporine. • Amplification of the biosynthetic gene cluster had obvious effect on improving the production of staurosporine. • The highest yield of staurosporine was achieved to 4568mg/L by stepwise increase strategy.

Improvement of ε-Poly-l-lysine Production by Co-Culture Fermentation Strategy

ε-poly-l-lysine (ε-PL) has been routinely used as a natural and safe preservative for many years in the food industry. However, most existing production methods struggle to achieve low cost and high production simultaneously. In this work, we present a co-culture fermentation strategy to enhance ε-PL production. Specifically, we screened a strain from five different strains that could be co-cultured with Streptomyces albulus to raise the production of ε-PL. Subsequently, a single factor experiment and response surface design were used to optimize the conditions of co-culture fermentation to further improve the production of ε-PL. Moreover, the optimal fermentation process was successfully verified in a 2-L fermentor with fed batch fermentation. The production of ε-PL reached 27.07 ± 0.47 g/L by 144 h. Compared with single strain (S. albulus) fermentation, the production of ε-PL was increased by 31.47%. At the same time, the amount of bacteria increased by 19.62%, which means that the ε-PL synthesis ability of bacteria had been improved. All the obtained results showed great potential for co-culture fermentation in large-scale ε-PL production and provide a new fermentation strategy for ε-PL biosynthesis.

Genetic modification of acetogens and optimization of fermentation process in C1-gas bioconversion

The current linear economy model relies on fossil energy and increases CO2 emissions, which contributes to global warming and environmental pollution. Therefore, there is an urgent need to develop and deploy technologies for carbon capture and utilization to establish a circular economy. The use of acetogens for C1-gas (CO and CO2) conversion is a promising technology due to high metabolic flexibility, product selectivity, and diversity of the products including chemicals and fuels. This review focuses on the physiological and metabolic mechanisms, genetic and metabolic engineering modifications, fermentation process optimization, and carbon atom economy in the process of C1-gas conversion by acetogens, with the aim to facilitate the industrial scale-up and carbon negative production through acetogen gas fermentation.

Analysis of the contribution of koji-making with Z. rouxii on volatile compounds of soy sauce

The co-inoculation fermentation of different microorganisms plays a crucial role in soy sauce fermentation in terms of enriching the composition of the volatile compounds. Therefore, the present study sought to investigate the effect of co-inoculation fermentation of Aspergillus oryzae and Zygosaccharomyces rouxii on the dynamics of volatile compounds in soy sauce using the combination of gas chromatography-mass spectrometry (GC-MS) and multivariate correlation analysis. A total of 124 volatile compounds were identified by A. oryzae and Z. rouxii inoculation alone and co-inoculation, including hydrocarbons, fatty acids, phenols, fatty esters, and benzamides. The content of phenylethyl alcohol, ethyl linoleate, and ethyl palmitate was significantly increased, and the metabolic pathways of multiple volatile compounds were affected in soy sauce inoculated with Z. rouxii. The present study results potentially contribute to the optimization of soy sauce fermentation processes.

Dynamic changes of active substances of rice, Pueraria and yam fermentation by Monascus ruber

Monascus spp., a fungus of medicine food homology, produces various beneficial secondary metabolites such as monacolin K (MK) during fermentation. In this study, the mixed fermentation of Monascus with rice, Pueraria, and yam has been systematically investigated. Single-factor and response surface methodology (RSM) were carried out to maximize MK content, and the optimized fermentation results showed that the content of MK reached 1.40 ± 0.04 mg/g. The optimal fermentation process determined the ratio of 8: 1: 1 for rice, Pueraria, and yam, respectively, the inoculation amount was 106 spores/mL, fermentation time was 15 days. Further analysis of the content of active substance in the fermentation process revealed that the β-glycosidase activity increased, the amylase enzyme activity decreased, the dioscin content decreased by 19.5%, and the diosgenin content increased by 175%, suggesting that there was a dynamic equilibrium relationship among the changes of active substances. This study aims at provide a basis and reference for the research of Monascus fermented foods by medicine food homology raw materials.

Fermentation process optimization and efficacy evaluation of functional yoghurt supplemented with Inonotus obliquus polysaccharide

Fermentation process optimization and efficacy evaluation of functional yoghurt supplemented with Inonotus obliquus polysaccharide

Advances in biosynthesis of higher alcohols in Escherichia coli.

In recent years, the development of green energy to replace fossil fuels has been the focus of research. Higher alcohols are important biofuels and chemicals. The production of higher alcohols in microbes has gained attention due to its environmentally friendly character.Higher alcohols have been synthesized in model microorganism Escherichia coli, and the production has reached the gram level through enhancement of metabolic flow, the balance of reducing power and the optimization of fermentation processes. Sustainable bio-higher alcohols production is expected to replace fossil fuels as a green and renewable energy source. Therefore, this review summarizes the latest developments in producing higher alcohols (C3-C6) by E. coli, elucidate the main bottlenecks limiting the biosynthesis of higher alcohols, and proposes potential engineering strategies of improving the production of biological higher alcohols.This review would provide a theoretical basis for further research on higher alcohols production by E. coli.

Sensory and microbial analyses on naturally lacto-fermented cucumbers

A solution of 2.5% salt with 15% crystal sugar was used for developing naturally fermented cucumbers. Fermented food sensory characteristics, color difference, and microbial analyses have not been yet investigated. To clarify this puzzle, changes in naturally fermented cucumber characteristics through the aging period were analyzed in this study. The results show that sensory evaluation and color difference in the fermented product improved significantly through the optimal fermentation process. Both total plate count and lactic acid bacteria count significantly and time-dependently increased. Importantly, Leuconostoc mensenteroides were identified as the dominant lactic acid bacteria. Leuconostoc mensenterosides significantly increased from 33.64% to 80.72% through the 8-days optimal aging process. Detrimental Enterobacter unclassified bacteria markedly decreased from 35.45% to 3.34%. Based on the overall changes in sensory evaluation, color difference and microbiota, naturally lacto-fermented cucumbers were developed and may be further exploited in the food industry.

Evaluation of fermentation properties, antioxidant capacity in vitro and in vivo, and metabolic profile of a fermented beverage made from apple and cantaloupe

This work is aimed at developing a fermented beverage (FB) with excellent antioxidant capacity from apple and cantaloupe using lactic acid bacteria (LAB) and yeast. The optimal fermentation process was as follows: the apple-cantaloupe juice adding 21% sugar inoculated with 9% yeast was fermented at 27 °C for 11 d, and then inoculated with 9% LAB at 36 °C for 16 d. The antioxidant activity of FB was investigated using in vitro and in vivo models. The total phenols content (TPC) and total flavonoids content (TFC), DPPH and ABTS radical scavenging activity, and Fe3+ reducing power of FB enhanced during in vitro simulated digestion. The in vivo studies indicated that 6.25% FB prolonged the lifespan of Caenorhabditis elegans, enhanced SOD and GSH-Px activity, decreased MDA content, and had significant anti-stress, but did not damage the growth, reproduction and locomotion of Caenorhabditis elegans. Untargeted metabolomics were performed to reveal the changes in metabolites of juice before and after fermentation. A total of 624 metabolites were identified. The significant differentially regulated metabolites were concentrated mainly in lipids and lipid-like molecules, organic acids and derivatives, and organic heterocyclic molecule. Thus, a bioactive food product with antioxidant properties was obtained by fermentation.

Impact of Curved‐Blade Impellers on Gas Holdup and Liquid Homogenization Dynamics in Stirred Tanks

AbstractDesign and optimization of aerobic fermentation processes in stirred tanks must factor in specific features, such as the formation of gas cavities on the rear of impeller blades and the need for high power input. Here, the ability of a curved‐blade impeller to reduce these drawbacks, which are typical of flat‐blade impellers, is investigated. The analysis is based on gas holdup distributions and liquid homogenization dynamics collected by electrical resistance tomography in a pilot‐scale stirred tank of geometry similar to typical industrial aerated fermenters. A wide range of gas flow rates and impeller speeds in single‐impeller and multiple‐impeller configurations are considered and the differences arising when a Rushton turbine is replaced with a Bakker turbine are discussed.

Efficient production of α-pinene through identifying the rate-limiting enzymes and tailoring inactive terminal of pinene synthase in Escherichia coli

α-Pinene has been indicated as an ideal biofuel or fuel precursors. The higher energy value and broad application of pinene dimers has recently been evaluated as a promising high-density jet fuel. In this work, the microbial de novo synthesis of α-pinene inEscherichia coliwas optimized by applying a systematic approach. Firstly, a complete biosynthetic process to α-pinene was constructed by bioprospecting the key enzymes pinene synthase (PtPS1Q457L) and geranyl diphosphate synthase (AgGPPS). Subsequently,the appropriate N-terminal truncated sites of pinene synthase were determined by analyzing the hydrophilicity/hydrophobicity of PtPS1Q457L. The accumulation of extracellular α-pinene was further increased 2.5 times by tailoring an appropriate length of inactive terminal of pinene synthase. Fine-tuning of IPTG concentration and induction point led to the synthesis of α-pinene at the yield of 541.8 mg/L at the shake flask level.Finally, further optimization of the fed-batch fermentation process enabled a α-pinene titer of 1035.1 mg/L in a 1.3L bioreactor, which is the highest according to currently available reports.