Optimization Of Fermentation Conditions Research Articles

Response Surface Methodology and Artificial Neural Network Optimization and Modeling of the Saccharification and Fermentation Conditions of the Polyhydroxybutyrate from Corn Stover

In this study, a response surface methodology (RSM) and artificial neural network (ANN) were used for the modeling and optimization of the enzymatic hydrolysis and fermentation conditions of the polyhydroxybutyrate (PHB) production from pretreated corn stover. Using three factors in each process, a face-centered central composite Design (FCD) was employed to optimize the reducing sugar yield (RSY), biomass, and PHB production of the saccharification and fermentation, respectively. The optimal conditions (RSY of 0.539 g/g) for enzymatic saccharification were 9.776% w/v solids loading, 83.656 FPU/g enzyme loading, and 18 h saccharification time. It was found that solids loading had the greatest impact on RSY. On the other hand, the optimum fermentation medium conditions were 19.727 g/g C/N ratio, 18.421 g/g C/P ratio, and 9.623 mL of trace elements solution (TES) per liter of fermentation medium, with a maximum PHB concentration of 7.083 g/L. During the fermentation of corn stover hydrolysate medium, the C/N ratio positively affected the growth and the PHB productivity of the microorganism. Moreover, the reliability of the RSM and ANN methods in modeling and predicting the RSY, biomass, and PHB concentrations were compared. The ANN showed higher accuracy compared to the RSM models. This study proved that the microorganism could synthesize PHB under optimal fermentation conditions using the reducing sugars from the enzymatic saccharification of pretreated corn stover.

Optimization of bioethanol production from sugarcane molasses by the response surface methodology using Meyerozyma caribbica isolate MJTm3

PurposeYeast strains tolerant to a wide range of stress conditions are needed for the production of bioethanol from substrates rich in sugar. In our earlier research findings, Meyerozyma caribbica isolate MJTm3 (OM329077) demonstrated remarkable stress tolerance and fermentative activity. The present study aimed to optimize six fermentation parameters to generate conducive fermentation conditions for ethanol production by M. caribbica isolate MJTm3.MethodThe response surface method (RSM) based on central composite design (CCD) was employed to optimize process conditions for higher bioethanol yield. The optimization process was carried out based on six independent parameters, namely temperature (25–35 °C), pH (5.5–6.5), inoculum size (10–20% (v/v)), molasses concentration (25–35 (w/v)), mixing rate (110–150 rpm), and incubation period (48–72-h). Analysis of ethanol concentration was done by HPLC equipped with a UV detector.ResultThe optimal conditions of the parameters resulting in a maximum predicted ethanol yield were as follows: pH 5.5, an inoculum size of 20%, a molasses concentration of 25 °Bx, a temperature of 30 °C, an incubation period of 72-h, and a mixing rate of 160 revolutions per minute (rpm). Using the above optimum conditions, the model predicted a bioethanol yield of 79%, 92% of the theoretical yield, a bioethanol concentration of 49 g L−1, and a productivity of 0.68 g L−1 h−1. A batch fermentation experiment was carried out to validate the predicted values and resulted in a bioethanol yield of 86%, 95% of theoretical yield, a bioethanol concentration of 56 g L−1, and productivity of 0.78 g L−1 h−1. On the other hand, the surface plot analysis revealed that the synergistic effect of the molasses concentration and the mixing rate were vital to achieving the highest bioethanol yield. These values suggested that the RSM with CCD was an effective method in producing the highest possible output of bioethanol from molasses in actual operation.ConclusionThe study confirmed the potential of using M. caribbica isolate MJTm3 for bioethanol production from sugarcane molasses under the abovementioned optimal fermentation conditions.

Optimization of fermentation conditions for protease production from Bacillus subtilis

In the paper, the fermentation conditions and fermentation medium of bacillus subtilis protease production were optimized to improve the outcome of the protease produced from bacillus subtilis to provide premium raw materials for the subsequent preparation of chitin from crab shell. The optimal fermentation conditions are temperature at 39°C, pH value of 7.5, fermentation time of 60h, inoculum size of 5%, filling volume of 80/250mL, and rotational speed at 180r/min; the optimal medium component ratio is 1.25% for starch mass concentration, 1% for yeast paste mass concentration, and 0.3% for sodium dihydrogen phosphate mass concentration. The activity of protease produced from bacillus subtilis GC021 is 174.87U/mL under the optimal fermentation conditions and at the optimal medium component ratio.

Computation-aided studies related to the induction of specialized metabolite biosynthesis in microbial co-cultures: An introductory overview

Co-cultivation is an effective method of inducing the production of specialized metabolites (SMs) in microbial strains. By mimicking the ecological interactions that take place in natural environment, this approach enables to trigger the biosynthesis of molecules which are not formed under monoculture conditions. Importantly, microbial co-cultivation may lead to the discovery of novel chemical entities of pharmaceutical interest. The experimental efforts aimed at the induction of SMs are greatly facilitated by computational techniques. The aim of this overview is to highlight the relevance of computational methods for the investigation of SM induction via microbial co-cultivation. The concepts related to the induction of SMs in microbial co-cultures are briefly introduced by addressing four areas associated with the SM induction workflows, namely the detection of SMs formed exclusively under co-culture conditions, the annotation of induced SMs, the identification of SM producer strains, and the optimization of fermentation conditions. The computational infrastructure associated with these areas, including the tools of multivariate data analysis, molecular networking, genome mining and mathematical optimization, is discussed in relation to the experimental results described in recent literature. The perspective on the future developments in the field, mainly in relation to the microbiome-related research, is also provided.

Bioactivity of Ganoderma lucidum and optimization of mycelial fermentation conditions

Ganoderma lucidum is a very precious traditional Chinese medicine. It has good pharmacological effects because of its polysaccharides, triterpenoids and other biological activities. Ganoderma lucidum mycelium is rich in Ganoderma lucidum polysaccharides and other substances, but it is difficult to obtain under natural conditions, so it is generally obtained through artificial inoculation or fermentation. Therefore, it is imperative to optimize the mycelium fermentation conditions. The range of fermentation time, temperature and pH of response surface analysis was determined by single factor experiment. The optimal fermentation conditions were fermentation temperature 28℃, pH=7, fermentation time 7 days, and mycelium biomass of (7±0.1) g/L. The results provide data reference for better utilization and development of Ganoderma lucidum.

Chemical structure, properties and potential applications of surfactin, as well as advanced strategies for improving its microbial production

Surfactin, a cyclic lipopeptide produced by microbes belonging to the genus Bacillus, is one of the most effective biosurfactants available in many industrial fields. However, its low production and high cost have intensively constrained its commercial applications. In this review, we first summarize the molecular structure, biological properties, beneficial roles and potential applications of surfactin in the fields of medical care and food safety, highlighting the great medical and commercial values of making its industrial production into reality. Further, genetic regulation for surfactin biosynthesis and advanced strategies for enhancing its microbial production, including optimizing fermentation conditions, rational genetic engineering and synthetic biology combined with metabolic engineering approaches, are elucidated. Finally, prospects for improving surfactin biosynthesis are discussed, and the establishment of suitable chassis hosts for exogenous production of surfactin might serve as an important strategy in future research.

Effect of Time, pH, and Yeast Concentration on Bioethanol Levels in the Ulva sp. Fermentation Process

Bioethanol is a form of renewable energy that is used to reduce dependence on the use of fossil fuels which cause various negative impacts on the environment. Ulva sp. contains high carbohydrates so it has the potential as a raw material for bioethanol production. This study aims to determine the optimum conditions of the fermentation process with the variables used time, pH, and yeast concentration. This study used the results of hydrolysis of Ulva sp. with optimum operating conditions of 0.1 N HCl concentration, 80 mesh particle size, and 450 watt microwave power. Measurement of bioethanol levels was carried out using an alcoholmeter. The results showed that the optimal conditions for fermentation were 7 days of fermentation, pH 5.5, and yeast concentration of 1.5% which resulted in a bioethanol content of 7.55%.

Optimization of Solid-Phase Lactobacillus Fermentation Conditions to Increase γ-Aminobutyric Acid (GABA) Content in Selected Substrates

The purpose of this study was to optimize conditions of solid-phase fermentation of lactic acid bacteria to enhance GABA contents in grains. Optimal solid-phase fermentation conditions that could enhance the GABA content after fermenting Oryza sativa (brown rice) were investigated by changing the Lactobacillus strain, fermentation temperature, fermentation time, and inoculated bacteria number. Avena sativa, Cicer arietinum, and red and brown Lens culinaris were then fermented using the optimal solid-phase fermentation conditions to measure changes in GABA content and antioxidant activity. As a result of the experiment, the optimal solid-phase fermentation conditions to enhance the GABA contents in grains were: fermentation time, 48 h; amounts of bacteria, inoculating 5% of 1 × 107 CFU/mL of lactic acid bacteria; and fermentation temperature, 36 °C. When fermented under this condition, the GABA content increased from 4.64 mg/g to 6.93 mg/g (49.0%) compared to unfermented raw material. The results of the DPPH and ABTS radical scavenging activity assays confirmed that both the GABA content and radical scavenging activity were increased after fermentation. Such solid fermentation conditions developed in this study can be used to support the development of health functional food materials with enhanced GABA content and antioxidant activity.

High-yield production of single-cell protein from starch processing wastewater using co-cultivation of yeasts

Single-cell protein (SCP) from potato starch processing wastewater (PSPW) shows great potential against protein scarcity and unsustainable production of plant and animal proteins. In this study, five yeasts were selected to conduct a series of PSPW fermentation for obtaining high-value SCP by optimizing fermentation conditions. The yeast combination was optimized as Candida utilis, Geotrichum candidum and Candida tropicalis with the volume proportion of 9:5:1. The inoculum size, temperature, rotation speed and initial pH were optimized at 12 %, 24℃, 200 r·min−1 and ∼ 4.13 (natural pH), respectively. At the optimal conditions, SCP yield of 3.06 g·L−1 and water-soluble protein of 17.32 % were obtained with the chemical oxygen demand removal of 56.9 %. A resource-recycling process of PSPW was proposed by coupling yeast fermentation and up-flow anaerobic sludge blanket (UASB) treatment to achieve simultaneous high-level organic removal and SCP production, which could be a promising alternative technology for PSPW treatment.

Development of a whey-based beverage with enhanced levels of conjugated linoleic acid (CLA) as facilitated by endogenous walnut lipase

In this study, optimization of fermentation conditions, and applying endogenous walnut lipase were investigated for the manufacture of a fermented, whey-based beverage containing conjugated linoleic acid (CLA). Among different commercial starter and probiotic cultures, the culture containing Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus showed high potency for CLA synthesis. The fermentation time and the type of walnut oil (lipolyzed or non-lipolyzed) had significant effects on CLA production, as the highest CLA content (36 mg/g fat) was synthesized in the sample containing 1 % lipolyzed walnut oil fermented at 42 °C for 24 h. Moreover, fermentation time had the highest contribution on viable cell counts, proteolysis, DPPH scavenging activity, and final pH. A significant and positive correlation between cell counts and CLA content was also observed (r = +0.823, p < 0.05). This study establishes a cost effective approach for converting cheese whey to a value added beverage enriched with CLA.

Rapid Screening of High-Yield Gellan Gum Mutants of Sphingomonas paucimobilis ATCC 31461 by Combining Atmospheric and Room Temperature Plasma Mutation with Near-Infrared Spectroscopy Monitoring.

In this study, an efficient mutagenesis and rapid screening method of high-yield gellan gum mutant by atmospheric and room temperature plasma (ARTP) treatment combined with Near-Infrared Spectroscopy (NIRS) was proposed. A NIRS model for the on-line detection of gellan gum yield was constructed by joint interval partial least squares (siPLS) regression on the basis of chemical determination and NIRS acquisition of gellan gum yield. Five genetically stable mutant strains were screened using the on-line NIRS detection of gellan gum yield in the fermentation from approximately 600 mutant strains induced by ARTP. Remarkably, compared with the original strain, the gellan gum yield of mutant strain 519 was 9.427 g/L (increased by 133.5%) under the optimal fermentation conditions, which was determined by single-factor and response surface optimization. Therefore, the method of ARTP mutation combined with the NIRS model can be used to screen high-yield mutant strains of gellan gum and other high-yield polysaccharide strains.

Valorization of Citrus Reticulata Peels for Flavonoids and Antioxidant Enhancement by Solid-State Fermentation Using Aspergillus niger CGMCC 3.6189

The bioactive components and bioactivities of citrus peel can be enhanced with microbial fermentation. Accordingly, this study investigated the ability of Aspergillus niger CGMCC3.6189 to accumulate flavonoids in Citrus reticulata peel powder (CRPP) by solid-state fermentation (SSF). Under the optimal SSF conditions including 80% moisture, 30 °C, pH 4.0, 4 × 107 spores/g d.w. CRPP, and 192 h, the total phenolic content (TPC), total flavonoid content (TFC), and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) scavenging activities of fermented CRPP significantly increased by 70.0, 26.8, 64.9, and 71.6%, respectively. HPLC analysis showed that after fermentation, the contents of hesperidin, nobiletin, and tangeretin were significantly increased from 19.36, 6.31, and 2.91 mg/g to 28.23, 7.78, and 3.49 mg/g, respectively, while the contents of ferulic acid and narirutin were decreased under the optimal fermentation conditions. Fermentation time is one of the most important factors that affect the accumulation of flavonoids and antioxidant activity; however, extended fermentation time increased the darkness of CRPP color. Therefore, our study provides a feasible and effective SSF method to increase the bioactive components and the antioxidant activity of CRPP that may be used in food, nutraceutical, and medicinal industries.

Matrine-producing endophytic fungus Galactomyces candidum TRP-7: screening, identification, and fermentation conditions optimization for Matrine production.

Matrine (MA) is an alkaloid extracted from the root of genus Sophora with various pharmacological activities. Production of MA by endophytic fungi offers an alternative challenge to reduce the massive consumption to meet the increasing demand of MA. In the current study, the positive strains with MA producing ability were screened from endophytic fungal isolated from the root of Sophora tonkinensis Gagnep. Chromatographic analyses verified the identity of the produced MA. Among these fungi, Galactomyces candidum strain TRP-7 was the most valuable strain for MA production with the initial yield 8.26mg L-1. The MA production was efficiently maximized up to 17.57mg L-1 of fermentation broth, after optimization of eight process parameters using Plackett-Burman and Box-Behnken designs. The statistical optimization resulted in a 1.127 times increase in MA production as compared to the initial yield of TRP-7. This is the first report to isolate endophytic fungi with MA-producing activity from S. tonkinensis Gagnep., and to identify an endophytic fungus G. candidum TRP-7 as a new promising start strain for a higher MA yield.

Mannitol Production from Fructose by Using Resting Cells of Methylotrophic Yeasts

Background: Mannitol is a polyol sugar widely used in pharmaceutical and food industries which can be produced by bioconversion. Using of resting cells and methanol as a carbon source are strategies to increase the efficiency of mannitol production by increasing NAD(P)H needed in the reduction process. Objectives: This research aimed to optimize bioconversion condition by using resting cells of methylotrophic yeasts with methanol and fructose as carbon source and substrate, respectively. Methods: Several isolates were used including Candida sp, Debaryomyces nepalensis and Debaryomyces hansenii and three species suspected to be yeast isolated from a local paddy field. The methylotrophic characteristic of the yeasts was screened by turbidometry. The optimization of fermentation condition was conducted by varying cultivation time (24-96 hours), resting cell concentration (30-140 mg/mL), fructose concentration (7.5-15%), ammonium sulphate concentration (0.25-0.75%) and aeration condition (50-80%). Quantitative analysis of the mannitol was conducted by HPLC with NH2 column and Refractive Index Detector. Results: D. hansenii showed the highest yield value in mannitol production (23.17%), followed by D. nepalensis, Isolate A and Candida sp. (6.52%, 6.50% and 4.38%, respectively). Variation of bioconversion condition using D. hansenii showed that the highest resting cell concentration (140 mg/mL) incubated for 72 hours, moderate fructose concentration (10%), the highest ammonium sulphate concentration (0.75%) and moderate aeration condition (70%) would result in the highest yield value of mannitol (60%). Conclusion: This finding showed the potency of D. hansenii in mannitol production and gave preliminary information of its optimum fermentation condition.

Isolation, identification and characterization of predominant microorganisms in Swazi traditional fermented porridge (incwancwa) and optimization of fermentation conditions

ABSTRACT The objective of the study was to isolate, identify and characterize the predominant microorganisms during the fermentation of incwancwa and optimize fermentation conditions. The lactic acid bacteria (LAB) load from fermented uncooked samples ranged from 4.6 ± 1.46 to 6.56 ± 0.2 log CFU/g whereas the load for yeast and coliforms ranged from 1.5 ± 0.39 to 2.12 ± 0.43 log CFU/g and 2.14 ± 0.22 to 4.09 ± 0.57 log CFU/g, respectively. LAB were the dominant microorganisms in incwancwa where Lueconostoc lactis was the main. Fermentation time and temperature had significant (p < .05) effect on the sensory perception of the product. The best temperature and time was found to be 32°C to 35°C for 8 to 24 hours. Numerical optimization predicted that the preferred temperature and time combination was 35°C for 15 hours. Thus, it is feasible to produce an acceptable incwancwa product under temperature/time conditions of 35°C for 15 hours using starter cultures derived from the original indegonuos flora of traditional incwancwa.

Optimization of Bacillus subtilis NRC1 growth conditions using response surface methodology for sustainable biosynthesis of gold nanoparticles

Gold nanoparticles (AuNPs) have different unique properties and a wide range of applications in different fields. Thereby, there is a growing urgency for the production of AuNPs using a safe and an economic method. In this study, optimization of fermentation conditions by Bacillus subtilis NRC1 for extracellular AuNPs synthesis using response surface methodology was achieved. The data obtained from Plackett–Burman design followed by Box–Behnken design indicated the accuracy and reliability of the model and it could be used to navigate the design space with a reasonable accuracy. Numerical optimization of Bacillus subtilis NRC1 active extracellular filtrate production, showed the optimum conditions of 0.74% (w/v) casein hydrolysate, 3.99% (w/v) dextrin, 47 × 106 CFU/ml inoculum size at pH 7.76 and 25 ^circC to give the maximum AuNPs biosynthesis. The model was highly valid and the obtained data had a confidence factor of 98.48%. Statistical optimization resulted in a 2.6-fold increase in AuNPs production compared with that of the non-optimized medium.

Optimization of Cordyceps sinensis fermentation Marsdenia tenacissima process and the differences of metabolites before and after fermentation

In this paper, we explored the interaction of factors which influenced the Cordyceps sinensis fermentation Marsdenia tenacissima (Roxb.) Wight et Arn, a Dai (a national minority of China) medicine, and the optimal fermentation conditions. The differences of C. sinensis metabolites in normal state (CN) and products of two-way liquid fermentation of C. sinensis and Marsdenia tenacissima (CM) and Marsdenia tenacissima (MT). The interactive effect of factors was analyzed and the best conditions are obtained through the box-behnken design (BBD) in response surface methodology (RSM). All metabolites were determined by ultra high performance liquid chromatography quadrupole time of flight mass spectrometer (UHPLC-Q-TOF-MS), analyzed and identified by metabonomics technology. Results showed that the optimum fermentation conditions were the concentration of raw medicinal materials is 160 g/L, the fermentation time is 6 days, the inoculation volume is 9.5%, the rotating speed is 170 rpm. 197 metabolites were identified in both positive ion and negative ion. 119 metabolites were significantly different between CN and CM. 43 metabolites were significantly different between CM and MT. Differential metabolic pathways were enriched. In conclusion, this paper optimizes the bidirectional fermentation process of M. tenacissima and C. sinensis through response surface methodology, and analyzes the changes of components from the level of metabonomics, so as to provide reference for exploring medicinal fungi fermentation of traditional Chinese medicine.

Solid-state fermentation produces greater stearidonic acid levels in genetically engineered Mucor circinelloides.

Omega-3 (ω-3) polyunsaturated fatty acids (PUFAs) are important dietary components due to their health benefits and preventative role in cardiovascular disease. Fish-based and plant seed oils are rich in stearidonic acid (SDA; 18:4, n-3), which are readily metabolized into ω-3 PUFAs such as eicosapentaenoic acid. However, these natural sources of SDA are generally low yielding and are unlikely to meet global demands, so new sustainable microbial fermentative sources of SDA need to be identified. Expression of delta15-desaturase in the oleaginous filamentous fungus Mucor circinelloides (McD15D) has been used to construct a recombinant SDA-producing McD15D strain that produces 5·0% SDA levels using submerged fermentation conditions. Switching to solid-state fermentation conditions in the same medium with submerged fermentation resulted in this engineered strain producing significantly higher amounts of SDA. A Box-Behnken design of response surface methodology approach has been used to identify optimal glucose and ammonium tartrate concentrations and temperature levels to maximize SDA production. The use of these optimal solid-state fermentation conditions resulted in the spores and mycelium of the recombinant McD15D producing 19·5% (0·64 mg g-1 ) and 12·2% (1·52 mg g-1 ) SDA content, respectively, which represents an overall increase in SDA yield of 188·0% compared with SDA yields produced using submerged fermentation conditions.

Effective gossypol removal from cottonseed meal through optimized solid-state fermentation by Bacillus coagulans

BackgroundCottonseed meal (CSM) is the main by-product of the cottonseed oil extraction process with high protein content, which is an important protein source for feed industry. However, CSM contains free gossypol (FG), a toxic substance that is detrimental to animal health and greatly limits its application. Microbial fermentation is currently considered to be one of the most effective methods to reduce FG and other anti-nutritional factors in CSM. Previously, yeast and bacteria species are used for degradation of FG in CSM, but showing less detoxification efficiency. Bacillus coagulans combines the properties of both lactic acid bacteria and Bacillus, producing both lactic acid and spores, and is considered a potential probiotic. In this study, we aimed to evaluate and optimize the effect of the solid-state fermentation process using a Bacillus coagulans to gossypol removal contained cottonseed meal.Results36 B. coagulans strains were isolated and found to have the ability to remove free gossypol. Through the evaluation of strains and optimization of fermentation conditions including fermentation temperature, ratio of material to water, inoculation amount, fermentation time and pH, we have established a solid-state fermentation process using a Bacillus coagulans strain S17 on CSM substrate with 1:1 of the material-to-water ratio, 15% (v/w) seed inoculation, 2% expanded corn flour, 1% bran, and 0.3%-0.8% metal irons at 40 °C for 52 h. After fermentation, the FG content in CSM was reduced from 923.80 to 167.90 mg/kg with 81.83% detoxification efficiency. Meanwhile, the crude protein content in CSM increased from 47.98 to 52.82%, and importantly, the spore concentration of strain S17 reached 1.68 × 1010 CFU/g dry material.ConclusionThe study showed that B. coagulans have the potential strong ability to degrade free gossypol through cottonseed meal fermentation. This study presents a feasible process for improving the resource utilization rate and nutritional value of CSM via solid-state fermentation through B. coagulans S17.

A method for efficient conversion of dehydrated cabbage waste liquid into high ester vinegar.

The utilization of wastewater in food processing factory has become one of the foremost essential and challengeable problems. In this study, cabbage wastewater was used for a mixed fermentation to obtain a high ester vinegar. The effect of fermentation conditions on the total acid content and total ester content of vinegar was investigated through single-factor experiments and response surface methodology analysis. Under the optimal fermentation conditions of10.61%inoculation amount, 4.9%initial alcohol content, 29.62°Cfermentation temperature, 75.21hfermentation time, and the exogenous esterification addition amount of 0.6%. The blending vinegar has a total acid content of 3.80g 100mL-1 and a total ester content of 30.52mgmL-1. The significant flavor components in the blending vinegar of the ethyl lactate with a pleasant aroma accounted for 22.15% and the ethyl acetate with a strong fruit aroma accounted for 11.37%.