Optimization Of Fermentation Conditions Research Articles

Fermentation of brown seaweeds Alaria esculenta and Saccharina latissima for new product development using Lactiplantbacillus plantarum, Saccharomyces cerevisiae and kombucha SCOBY

Two seaweed species were examined (Alaria esculenta and Saccharina latissima) as a fermentation feedstock for the development of a beverage. Three microbial groups were selected for experimentation; a single-species bacterium; Lactiplantibacillus plantarum, a single-species yeast; Saccharomyces cerevisiae and a multi-species culture; kombucha SCOBY (Symbiotic Culture of Bacteria and Yeast). Results showed SCOBY cultures were more successful in fermenting A. esculenta than S. latissima due to the lowered glucose content (4.069 ± 0.174 mg / mL and 12.224 ± 2.249 mg / mL, respectively). Likewise, L. plantarum played a major role in fermenting S. latissima, over A. esculenta, resulting in a lowered pH in the former but not the latter (6.44 ± 0.040 and 4.825 ± 0.045, respectively). S. cerevisiae does not appear to have been suitable as a fermentation medium for these two seaweed species under these conditions due to the lack of pH lowering, glucose reduction and acid production. All treatments showed an increased production of lactic acid, especially the SCOBY treated samples, which is an indicator of fermentation. There is potential for optimization of the seaweed fermentation process through strain selection, fermentation conditions optimization (temperature, time, pH) and seaweed biomass pretreatment. Glutamic acid, the amino acid responsible for umami flavour, was found in greater quantities in the S. cerevisiae treated seaweed, indicating that fermentation using S. cerevisiae cultures may improve the umami flavour profile of a seaweed fermented beverage product. In order to see if the seaweed species used had an impact on the SCOBY microbial makeup, the DNA profiles of the two SCOBYs used were analyzed. There were significant differences between the two SCOBYs. The A. esculenta SCOBY showed slightly rarer species of fungi and the species abundance of fungi was greater than that of S. latissima SCOBY. Furthermore, the number of fungal operational taxonomic units (OTUs) in A. esculenta SCOBY was higher than that in S. latissima SCOBY. This study shows the potential of using brown seaweed species as a fermentation substrate to develop a novel, fermented beverage.

Novel Strain of Paenibacillus phyllosphaerae CS-148 for the Direct Hydrolysis of Raw Starch into Glucose: Isolation and Fermentation Optimization.

The conventional process for converting starch to glucose is energy-intensive. To lower the cost of this process, a novel strain of Paenibacillus phyllosphaerae CS-148 was isolated and identified, which could directly hydrolyze raw starch into glucose and accumulate glucose in the fermentation broth. The effects of different organic and inorganic nitrogen sources, the culture temperature, the initial pH, and the agitation speed on the yield of glucose were optimized through the one-factor-at-a-time method. Nine factors were screened by Plackett-Burman design, and three factors (raw corncob starch, yeast extract and (NH4)2SO4) had significant effects on glucose yield. Three significant factors were further optimized using Box-Behnken design. Under the optimized fermentation conditions (raw corncob starch 40.4 g/L, yeast extract 4.27 g/L, (NH4)2SO4 4.39 g/L, KH2PO4 2 g/L, MgSO4`7H2O 2 g/L, FeSO4`7H2O 0.02 g/L, NaCl 2 g/L, KCl 0.5 g/L, inoculums volume 4%, temperature 35 °C, agitation rate 150 rpm, and initial pH 7.0), the maximum glucose yield reached 17.32 ± 0.46 g/L, which is 1.33-fold compared to that by initial fermentation conditions. The maximum conversion rate and glucose productivity were 0.43 ± 0.01 g glucose/g raw corn starch and 0.22 ± 0.01 g/(L·h), respectively. These results implied that P. phyllosphaerae CS-148 could be used in the food industry or fermentation industry at a low cost.

Valorization of Different Dairy By-Products to Produce a Functional Dairy–Millet Beverage Fermented with Lactobacillus paracasei as an Adjunct Culture

Fermented dairy products not only have a long shelf-life but also have beneficial nutritional values. The products are deficient in dietary fiber and certain bioactive compounds. Adding grains to dairy products is a widespread practice to improve the nutritional and economic aspects. In this work, we studied the effect of fermented millet–milk beverages (FMBs) using pearl millet grains and three different dairy by-products (sweet whey, sweet buttermilk, and skimmed milk). A control treatment prepared with water was also manufactured for comparison. Samples were continuously prepared and fermented using a commercial yogurt starter culture (YC-381) containing L. delbrueckii subsp. bulgaricus, Streptococcus thermophilus, and a pure strain of L. paracasei subsp. Paracasei. Four FMBs (water based: WB-FMB, whey based: WHB-FMB, buttermilk based: BMB-FMB, and skimmed milk based: SMB-FMB) were analyzed during cold storage at 4 °C for up to 15 days for chemical, microbiological properties, minerals content, antioxidant properties, glycemic index, and glycemic load on days 1, 8, and 15. The sensory characteristics of the FMBs were also evaluated during cold storage (4 °C/15 days). In general, the progression of acidity was slower in SMB-FMB and WHB-FMB samples during fermentation compared to in the BMB-FMB sample. The longest fermentation time was for the SMB-FBM sample (3 h), while the shortest was for the BMB-FMB sample (1.5 h). Reflecting the good manufacturing practices, all samples were free of coliform, mold, and yeast. No bacterial growth was detected in the WB-FMB sample at days 8 and 15 of storage, while the growth of Lactobacillus spp. and S. thermophilus was significantly higher (9.97 ± 0.01 and 9.48 ± 0.06, respectively) in the BMB-FMB sample compared to in the other three FMBs. The FMBs produced using dairy by-products had more antioxidant properties. All samples were better perceived during sensory evaluation by panelists than the water-based sample, except for the BMB-FMB sample, in which a bitter taste appeared. In the BMB-FMB sample, the proteolytic degree was significantly higher (4.8 ± 0.09) after 3 h of fermentation by about 460% than in the fresh sample. All samples had a low glycemic index and glycemic load. In addition, acidity progression was slower in SMB-FMB and WHB-FMB samples during fermentation and storage compared to the WB-FMB sample. Therefore, it could be recommended that it is more beneficial to prepare fermented millet–milk beverages using dairy by-products and suitable starter cultures under optimal fermentation conditions instead of using water to maximize the nutritional and economic aspects.

Effects of Zn2+ and Mn2+ on the photo-fermentative performance of HY01 in biohydrogen production from xylose fermentation

ABSTRACT The addition of specific ions has a significant effect on the characteristics and kinetics of hydrogen production by photofermentation (PFHP). In this article, a new basic research investigated by us find that adjusting the addition ratio of Zn2+ and Mn2+ ions in the R. sphaeroides HY01 system can effectively improve their biohydrogen production from xylose. The largest biohydrogen yield can be obtained as high as 219.2 mL/g xylose at concentration levels of 12 mg/L Zn2+ and 8 mg/L Mn2+. The shortest lag time is 5.76 h, along with most of the organic energy in the substrate transferred to H2. To evaluate the effect of Zn2+ and Mn2+, the Gompertz model with appropriately modification is applied on the photosynthetic bacteria R. sphaeroides HY01, and the corresponding constants are obtained by fitting the model, which is of great guiding significance for the optimization of fermentation conditions.

Optimization strategy for inulinase production by Aspergillus niger URM5741 and its biochemical characterization, kinetic/thermodynamic study, and application on inulin and sucrose hydrolysis.

Inulinases are enzymes of great interest in the food industry, especially due to their application in the synthesis of fructose and fructo-oligosaccharides. Moreover, some inulinases (I) also present invertase activity (S), making them useful for sucrose hydrolysis processes. In the present study, the production of inulinase by Aspergillus niger URM5741 was evaluated and optimized using two statistical approaches. First, the composition of the cultivation medium was determined through a simplex centroid mixture design, followed by the selection of optimal fermentation conditions using the Box-Behnken design. Based on these experimental designs, the maximum activities of inulinase (16.68 U mL-1) and invertase (27.80 U mL-1) were achieved using a mixture of wheat, soy, and oat brans (5g), along with 2.5% inulin and 40% moisture. The inulinase exhibited optimum temperature and pH of 60°C and 4.0, respectively, displayed a high affinity for both substrates, as evidenced by very-low Michaelis constant values (1.07-1.54mM). A relative thermostability was observed at 55-60°C as indicated by half-lives values (I: 169.06-137.27min; S: 173.29-141.52min) and D-values (I: 561.61-456.00min; S: 575.65-470.11min) which were further confirmed by the high activation energy (123.01 and 143.29kJmol-1). The enzyme demonstrated favorable results in terms of inulin and sucrose hydrolysis, being a maximum release of reducing sugars of 6.04 and 15.80g L-1, respectively. These results indicate that the sequential statistical approach proved to be beneficial to produce inulinase by A. niger URM5741, with the obtained enzyme considered promising for long-term industrial applications.

Optimizing the Fermentation Conditions of Cudrania tricuspidata Fruit Using Bacillus amyloliquefaciens for Anti-Inflammatory Activity and GC-MS-Based Volatile Component Characteristics.

The aim of this study is to optimize the performance conditions used for maximum anti-inflammatory activity and to clarify in vitroanti-inflammatory properties of fermented C. tricuspidata fruit. Based on the single-factor experiment and Box-Behnken design, the optimized fermentation conditions of C. tricuspidata fruit for maximum anti-inflammatory activity were 3.8 d fermentation period, 8.4% (v/w) inoculation concentration, and 29.2°C fermentation temperature. Under optimal conditions, anti-inflammatory activity-based nitric oxide of fermented C. tricuspidata fruit reached 93.9%. Moreover, this study provides a theoretical basis and experimental data containing β-hexosaminidase and reactive oxygen species for the medical use and industrialization of C. tricuspidata fruit fermentation. Interestingly, the results of GC-MS analysis confirmed that fermented C. tricuspidata fruits detect volatile components different from unfermented C. tricuspidata fruits. We suggested that this volatile component may have been involved in the anti-inflammatory reaction, but scientific verification of this is needed later. Therefore, an in-depth study of volatile components detected from fermented C. tricuspidata fruits will need to be conducted later.

Box–Behnken design to determine optimal fermentation conditions for apple-fortified mulberry wine using Saccharomyces bayanus

Wine is a fermented product of fruit juice. Mulberry and apple juice can also be used to produce wine. Several factors influence the alcoholic fermentation of the must; therefore, the optimization of the mulberry wine fermentation conditions with the dry yeast strain Saccharomyces bayanus (concentration varied from 0.15 to 0.25 g/L), fermentation conditions as pH value (from 3.5 to 4.5), and total soluble solid (TSS) content (24–28°Brix) were performed in this study. To evaluate the influence of these factors, a Box–Behnken design was used to minimize the number of factor combinations required, which allows the determination of optimal fermentation conditions (pH, TSS content, and dry yeast concentration) to produce wines with high alcohol and bioactive compounds (total anthocyanin (TAC) and polyphenol content (TPC)). Based on the analysis of experimental data, the second-order response surface models were developed to describe the relationship between initial pH value, TSS, and dry yeast concentration on wine quality acquisition (ethanol content and bioactive compounds). The results of the analysis of variance (ANOVA) showed that the model setup by response surface quadratic regression was suitable for predicting the wine quality. It was observed that the quality of the apple-fortified mulberry wine was significantly affected by all variables. The optimal contents of ethanol, total anthocyanin, and total polyphenol were achieved at 12.97% (v/v), 171.85 mg/L, and 87.17 mgGAE/L, respectively, when fermented in juice medium with optimal values of pH, TSS, and yeast concentration of 3.9, 26°Brix, and 0.22 g/L, respectively.

Purification and characterization of the low molecular weight xylanase from Bacillus cereus L-1.

Xylanase is widely used in various industries such as food processing, paper, textiles, and leather tanning. In this study, Bacillus cereus L-1 strain was isolated and identified as capable of producing low molecular weight xylanase through 16s rRNA sequencing. Maximum xylanase yield of 15.51 ± 2.08 U/mL was achieved under optimal fermentation conditions (5% inoculum, 20g/L xylan, pH 6.0, for 24h). After purification via ammonium sulfate precipitation and High-S ion exchange chromatography, electrophoretic purity xylanase was obtained with a 28-fold purification and specific activity of 244.97 U/mg. Xylanase had an optimal pH of 6.5 and temperature of 60°C and displayed thermostability at 30°C and 40°C with 48.56% and 45.97% remaining activity after 180min, respectively. The xylanase retained more than 82.97% of its activity after incubation for 24h at pH 5.0 and was sensitive to metal ions, especially Mg2+ and Li+. Purified xylanase showed a molecular weight of 23kDa on SDS-PAGE, and partial peptide sequencing revealed homology to the endo-1,4-beta-xylanase with a molecular weight of 23.3kDa through LC/MS-MS (liquid chromatography-tandem mass spectrometry). This study suggests that the purified xylanase is easier to purify and enriches low molecular weight xylanases from bacteria source.

Preparation and Improvement of Physicochemical and Functional Properties of Dietary Fiber from Corn Cob Fermented by Aspergillus niger.

Corn cobs were fermented with Aspergillus niger to produce soluble dietary fiber (SDF) of high quality and excellent food safety. In this work, the fermentation process was optimized by single-factor test and response surface methodology (RSM). The optimal fermentation conditions were determined to be a material-liquid ratio of 1:30, an inoculum concentration of 11%, a temperature of 32°C, a time of 6 days, and a shaking speed of 200 r/min. Under these conditions, the SDF yield of corn cob increased from 2.34% to 11.92%, and the ratio of soluble dietary fiber to total dietary fiber (SDF/TDF) reached 19.08%, meeting the requirements for high-quality dietary fiber (SDF/TDF of more than 10%). Scanning electron microscopy (SEM) and Fourier-transformed infrared spectroscopy (FT-IR) analysis revealed that the fermentation effectively degraded part of cellulose and hemicellulose, resulting in the formation of a loose and porous structure. After fermentation the water swelling capacity, water-holding capacity, and oil-holding capacity of the corn cob SDF were significantly improved and the adsorption capacity of glucose, cholesterol, and nitrite ions all increased by more than 20%. Moreover, the total phenolic content increased by 20.96%, which correlated with the higher antioxidant activity of SDF. Overall, the fermentation of corn cobs by A. niger increased the yield and enhanced the functional properties of dietary fiber (DF) as well.

Engineering Corynebacterium glutamicum for the efficient production of N-acetylglucosamine

N-acetylglucosamine (GlcNAc) is significant functional monosaccharides with diverse applications in medicine, food, and cosmetics. In this study, the GlcNAc synthesis pathway was constructed in Corynebacterium glutamicum and its reverse byproduct pathways were blocked. Simultaneously the driving force of GlcNAc synthesis was enhanced by screening key gene sources and inhibiting the GlcNAc consumption pathway. To maximize carbon flux, some competitive pathways (Pentose phosphate pathway, Glycolysis pathway and Mannose pathway) were weakened and the titer of GlcNAc reached 23.30 g/L in shake flasks. Through transcriptome analysis, it was found that dissolved oxygen was an important limiting factor, which was optimized in a 5 L bioreactor. Employing optimal fermentation conditions and feeding strategy, the titer of GlcNAc reached 138.9 g/L, with the yeild of 0.44 g/g glucose. This study significantly increased the yield and titer of GlcNAc, which lay a solid foundation for the industrial production of GlcNAc in C. glutamicum.

Rewiring Bacillus subtilis and bioprocess optimization for oxidoreductive reaction-mediated biosynthesis of D-tagatose

D-tagatose holds significant importance as a functional monosaccharide with diverse applications in food, medicine, and other fields. This study aimed to explore the oxidoreductive pathway for D-tagatose production, surpassing the contemporary isomerization-mediated biosynthesis approach in order to enhance the thermodynamic equilibrium of the reactions. Initially, a novel galactitol dehydrogenase was discovered through biochemical and bioinformatics analyses. By co-expressing the galactitol dehydrogenase and xylose reductase, the oxidoreductive pathway for D-tagatose synthesis was successfully established in Bacillus subtilis. Subsequently, pathway fine-tuning was achieved via promoter regulation and dehydrogenase-mediated cofactor regeneration, resulting in 6.75-fold higher D-tagatose compared to that produced by the strain containing the unmodified promoter. Finally, optimization of fermentation conditions and medium composition produced 39.57 g/L D-tagatose in a fed-batch experiment, with a productivity of 0.33 g/L/h and a yield of 0.55 mol/mol D-galactose. These findings highlight the potential of the constructed redox pathway as an effective approach for D-tagatose production.

Optimization of fermentation condition to produce liquid organic fertilizer (LOF) from rotten vegetable waste using response surface methodology

This study aims to optimize fermentation process of vegetable waste into liquid organic fertilizer (LOF). Materials used in this study are rotten vegetables obtained from the local market and bio-activator from the biogas pilot plant. Level of variables for LOF fermentation such as fermentation time and activator volume were adjusted by central composite design (CCD) and response surface methodology (RSM) was used to optimize process variables using JMP Pro ver. 13 software. This study observed except for yield of phosphorus (P) which is significantly correlated with fermentation time and bio-activator volume, other parameters such as pH, nitrogen (N), potassium (K), and carbon (C) are associated with time significantly but less significant with bio-activator volume. RSM predicted the best fermentation time to produce LOF was 11.17 days using bio-activator volume of 5.15 mL and pH level should be around 6 to 7.5. The LOF product under those optimum condition was predicted containing N, P K, and C approximately 0.15%, 0.042%, 0.27% and 0.58% respectively. Experimental verification had been carried out and t-test was used to compare the means of the observed and predicted data in this study. The experimental values were found significantly in agreement with the predicted N and P, but less significant for K with respect to t-Table. The t-test value indicates the predictive models were accepted. © 2001 Elsevier Science. All rights reserved.

Hermetia illucens Fermented with Lactobacillus plantarum KCCM12757P Alleviates Dextran Sodium Sulfate-Induced Colitis in Mice.

Inflammatory bowel disease (IBD) can severely affect humans and animals and is difficult to treat. Black soldier fly (Hermetia illucens; Hi) larvae (BSFL) are a sustainable source of protein. However, no studies exist on the antioxidant and anti-inflammatory functions of BSFL or fermented BSFL with respect to IBD. In this study, riboflavin-producing Lactobacillus plantarum KCCM12757P was isolated from a fish farm tank, and in conjunction with hot water-extracted Hi (HeHi) (termed HeHi_Lp), was used to determine optimal fermentation conditions to increase vitamin B2 concentration. This in vivo study investigated the therapeutic effects and mechanistic role of HeHi_Lp in chronic colitis-induced murine models. Histological changes, inflammatory cytokine levels, and intestinal barrier function were explored. Gut microbial communities and gene expression in the nuclear factor (NF)-κB signaling pathway were also studied. HeHi_Lp remarkably reduced the disease activity index, inflammatory cytokine (inducible nitric oxide synthase, cyclooxygenase 2, tumor necrosis factor α, interleukin (IL-6 and IL-1β) levels, and increased body weight and colon length. HeHi_Lp administration significantly raised zonula occludens 1, occludin and claudin 1 and improved the composition of the gut microbiota and beneficial intestinal bacteria. These results suggest that HeHi_Lp can be used as a dietary supplement in pet food to alleviate colitis.

Optimization of culture conditions for the production, antifungal activity and characterization of secondary metabolites of <i>Trichoderma longibrachiatum</i>

The present study was intended to optimize the culture conditions for secondary metabolite production by endophytic fungi. Based on the morphology and phylogeny, the fungus was identified as Trichoderma longibrachiatum isolated from brinjal leaf based on morphological characterization. The antifungal activity was evaluated against phytopathogens such as Macrophomina phaseolina, Phytopthora infestans, Colletotrichum falcatum and Colletotrichum gloeosporioides through the overlapping method, culture filtrate and organic fraction from Potato dextrose both as a growth medium. The organic fraction exhibited a significant antifungal activity, while modifications in medium composition may possess a major impact on the quantity and quality of secondary metabolites production. To achieve maximum metabolite production, the growth of the culture was optimized with screening of basal media, carbon, nitrogen, pH, trace elements and incubation period. The final optimized fermentation conditions were Minimal ereavis broth as basal media; glucose and sucrose as carbon source; Peptone and Yeast extract as nitrogen source, sodium nitrate as precursor; pH as 6; and incubation period as 7 days at 28°C. This optimization resulted in antifungal activity of 47.19-60.67% against M. phaseolina, P. infestans, C. falcatum, and C. gloeosporioides which was higher than that before optimization (43.80%). GCMS revealed distinct metabolites of T. longibrachiatum, comprising antifungal metabolites and molecules with additional bioactivities. These results strengthen ongoing research on disease control in agriculture by emphasizing the biocontrol potential of T. longibrachiatum isolated from brinjal phyllosphere against plant pathogenic fungi.

Genomic insights into antimicrobial potential and optimization of fermentation conditions of pig-derived Bacillus subtilis BS21.

Bacillus spp. have been widely used as probiotic supplements in animal feed as alternatives to antibiotics. In the present study, we screened a Bacillus subtilis strain named BS21 from pig feces. Antimicrobial activities, whole genome mining and UHPLC-MS/MS analysis were used to explore its antimicrobial mechanism. Strain BS21 showed Significant growth inhibition against a variety of animal pathogens, including Escherichia coli, Salmonella enterica Pullorum, Salmonella enterica Typhimurium, Citrobacter rodentium, Shigella flexneri and Staphylococcus aureus. Seven gene clusters involved in antimicrobial biosynthesis of secondary metabolites were encoded by strain BS21 genome, including four non-ribosomal peptides (bacillibactin, fengycin, surfactin and zwittermicin A), one ribosomal peptide (subtilosin A), one dipeptide (bacilysin) and one polyketide (bacillaene). Among them, production of surfactin, fengycin, bacillibactin, bacilysin and bacillaene was detected in the supernatant of B. subtilis strain BS21. To develop the potential application of BS21 in animal production, medium components and fermentation parameters optimization was carried out using response surface methodology (RSM). Production of antimicrobial secondary metabolites of strain BS21 was increased by 43.4%, and the best medium formula after optimization was corn flour 2%, soybean meal 1.7% and NaCl 0.5% with optimum culture parameters of initial pH 7.0, temperature 30°C, rotating speed at 220 rpm for 26 h. Our results suggested that strain BS21 has the potential for large-scale production and application as a potential source of probiotics and alternative to antibiotics for animal production.

Highly efficient production of polyhydroxybutyrate using an open dual one-pot fermentation by Halomonas alkalicola M2

The high cost associated with polyhydroxybutyrate (PHB) production demands immediate attention to advance its commercial viability. Herein, we innovatively construct highly efficient production of PHB from low-cost lignocellulosic biomass (LCB) using an open one-pot fermentation by the alkali-halophilic Halomonas alkalicola M2 developed in our previous work. We first develop alkaline pretreatment of LCB to achieve open one-pot fermentation and efficient conversion. Multi-objective optimization of fermentation conditions produces 103.421 mg/L of PHB with a content of 14.437 % and effectively promotes saccharification with cellulose and xylan enzymatic efficiencies of 82.948 % and 73.710 %, respectively. We then develop an open dual one-pot fermentation process, involving the conversion of lignin- and lignin-derived compounds-enriched slurry in the first pot and subsequent polysaccharide conversion in the second pot, to achieve efficient whole LCB components conversion, yielding a record 9.57 g/L of PHB. More importantly, we extend an open dual one-pot-fed-batch fermentation, producing 0.80 g/L of PHB with 27.69 % content in the first pot and 20.08 g/L of PHB with 61.86 % content in the second pot, showing significantly higher than many reported strains. Overall, this work demonstrates the effectiveness of utilizing cheap LCB in a newly designed fermentation process to produce PHB efficiently, representing a significant advancement in this field.

Fermentative production of 2,3-butanediol from cheese whey by a non-engineered mutant strain of Lactococcus lactis

Cheese manufacturing generates huge amounts of whey, part of it being disposed of as waste, posing serious environmental problems. However, whey is a valuable resource that can be valorized in a cost-effective and sustainable way, being fermentation processes a suitable option. The non-engineered mutant strain Lactococcus lactis 43103, a non-pathogenic microorganism, was found to efficiently produce 2,3-butanediol (2,3-BDO) from lactose. Culture of this strain in a whey-based medium adapted to its nutritional requirements under optimized fermentation conditions resulted in 2,3-BDO productions close to 18 g/L, representing 76.8 % of the maximum theoretical yield, which reached 94.7 % when acetoin, its immediate precursor in the metabolic pathway, was included. The fermentation performance was not very far from that of the best producers (natural or engineered) and was the best one among the non-pathogenic and non-engineered bacteria. These results open up the possibility of valorizing whey through fermentation to 2,3-BDO, a valuable platform chemical.

Comparing the differences of physicochemical properties and volatiles in semi-dry Hakka rice wine and traditional sweet rice wine via HPLC, GC–MS and E-tongue analysis

This study aimed to explore effects of indica rice addition, rice soaking time and rice soup addition on total sugar and alcohol content of semi-dry Hakka rice wine (HRW) and compare its difference in physicochemical properties and volatiles with traditional sweet rice wine (TSRW) via HPLC, GC–MS and E-tongue. The optimal fermentation conditions of semi-dry HRW were 50 % indica rice addition, 12 h rice soaking time and 85 % rice soup addition. The total sugar (16.13 mg/mL) of semi-dry HRW was significantly lower than that of TSRW (135.79 mg/mL), especially the trehalose, glucose, sucrose and maltose. Its alcohol content was significantly higher than that of TSRW. There were significant differences in volatile components between semi-dry HRW and TSRW, especially esters, alcohols and ketones, but no significant differences in organic acids and amino acids. Results obtained could provide reference data for improving the fermentation process and quality of semi-dry HRW.

Optimization of Fermentation Conditions and Product Identification of a Saponin-Producing Endophytic Fungus.

Some fungal endophytes isolated from P. ginseng may present a new method of obtaining saponins. This experiment aimed to optimize the total saponin yield produced through in vitro fermentation by an endophytic fungus and analyze its saponin species in the fermented extract. Fermentation protocols were optimized with a uniform design and verified through regression analysis to maximize the total saponin yield. The saponin types under optimal fermentation conditions were then identified and analyzed using Liquid Chromatography-Mass Spectrometry. The Trametes versicolor strain NSJ105 (gene accession number: OR144428) isolated from wild ginseng could produce total saponins. The total saponin yield could be increased more than two-fold through the optimization of fermentation conditions. The concentration of the total saponins achieved by the verified protocol 105-DP was close to the predicted value. The fermentation conditions of the 105-DP protocol were as follows: potato concentration 97.3 mg/mL, glucose concentration 20.6 mg/mL, inoculum volume 2.1%, fermentation broth pH 2.1, fermentation temperature 29.2 °C, and fermentation time 6 d. It was detected and analyzed that the fermented extract of 105-DP contained the ginsenosides Rf and Rb3. The endophytic fungus Trametes versicolor strain NSJ105 has potential application value in saponin production.

Optimization of fermentation conditions to improve the functional and structural characteristics of rapeseed meal with a mutant Bacillus subtilis species

This investigation aimed to provide the optimum solid-state fermentation (SSF) conditions to enhance the functional and structural characteristics of rapeseed meal (RM). Response Surface Methodology (RSM) was used to optimize the experimental fermentation conditions (temperature, incubation time, and inoculum size) on the protease activity, peptide content, and DPPH activity of RM with Central Composite Design (CCD). The quadratic models of the investigated responses were developed, and their coefficients were observed from the multiple-regression analysis. ANOVA indicated that incubation time was highly significant (p < .01) in all experimental responses. The optimized fermentation conditions of protease activity, peptide content, and DPPH activity were accessed at 92 h, 44 °C, and 8 mL, and the predicted data for these responses were 212.59 U/g, 192.35 mg/g, and 93.46%, respectively. The verification experiment indicated that the measured values of the three responses were insignificant (p > 0.05) with the predicted results, suggesting that the CCD model was fittingly used in predicting such responses. Scanning electron microscopy (SEM), atomic force microscopy (AFM), and Raman spectroscopy outcomes showed remarkable alteration in RM morphology, surface topography, and secondary conformation after 92 h of fermentation. Correlational analysis indicated that β-turn had a strong interrelationship with the functional properties (i.e., DPPH, total phenol content, and Emulsifying properties) of FRM. The improved parameters obtained displayed their effectiveness in improving the bioactive and structural properties of FRM.