Study on Solid Fermentation and Antioxidant Function of Natto

[Objectives]To study the optimum conditions of solid fermentation of natto with antioxidant function as an index.[Methods]Single factor experiment and orthogonal experiment were designed to study the effects of temperature,time,initial pH and inoculum amount on the antioxidant activity of natto solid fermentation.The optimum conditions of natto solid fermentation were determined and the antioxidant ac-tivity of natto extract was compared.[Results]The optimal fermentation conditions were as follows:temperature 32℃,initial pH 7.0,inocu-lation amount 8%,fermentation time 32 h.The hydroxyl radical scavenging rate of natto solid fermentation crude extract was the highest,which was 82.7%.The optimized nato fermentation extract showed stronger scavenging ability for-OH and O,:,and showed obvious dose-effect relationship.ICso was 3.63 and 4.24 mg/mL,respectively,and the scavenging efficiency was 1.3 and 1.9 times higher than that of the unoptimized fermentation extract,respectively.[Conclusions]Natto is rich in nattokinase and other functional factors,and its antioxidant ac-tivity can be improved by optimizing fermentation technology,so that natto products can be widely used,including cosmetic raw materials,nat-to skin care soap,health food and medicine,etc.,and have a broader development prospect.

Study on Sporulation Conditions of Trichoderma reesei by Solid Fermentation

[Objective] This study aimed to investigate the sporulation conditions of Tri- choderma reesei by solid fermentation. [Method] With sporulation yield as the response value, single-factor test, Plackett-Burmam design, steepest ascent test, BoxBehnken design and response surface analysis were employed to optimize the con- ditions for sporulation of Trichoderma reesei by solid fermentation. [Result] Based on single-factor test, the most appropriate carbon source for Trichoderma reesei was straw stalk powder and wheat bran with the ratio of 3：2 and optimal amount of 15 g/L; the most appropriate inorganic nitrogen was （NH4）2O4 with the optimal amount of 3 g/L. According to Plackett-Burmam design, moisture content, initial pH and incubation temperature were identified as significant factors affecting the sporulation yield of Trichoderma reeseL The maximum sporulation yield area was approached by steepest ascent test. Based on Box-Behnken design and response surface analysis, the optimal fermentation conditions for the maximum sporulation yield were determined as： straw stalk powder of 6 g/L, wheat bran of 9 g/L, （NH4）2SO4 of 3 g/L, moisture content of 65%, incubation temperature of 29 ℃, fermentation period of 72 h and initial pH of 5.5, under these conditions, the sporulation yield reached 2×10^10 spores/g, which was improved by 1.4 times compared with that before optimization. [Conclusion] In this study, the conditions for sporulation of Trichoderma reesei by solid fermentation were optimized with low-cost straw stalk powder and wheat bran as carbon sources, which was conducive to reducing the production cost of Trichoderma reesei and increasing the sporulation yield, showing certain social and economic significance.

Solid state fermentation of rapeseed cake with Aspergillus niger for degrading glucosinolates and upgrading nutritional value

Background： Rapeseed cake is a good source of protein for animal feed but its utilization is limited due to the presence of anti-nutritional substances, such as glucosinolates （GIs）, phytic acid, tannins etc. In the present study, a solid state fermentation （SSF） using Aspergillus niger was carried out with the purpose of degrading glucosinolates and improving the nutritional quality of rapeseed cake （RSC）. The effects of medium composition and incubation conditions on the GIs content in fermented rapeseed cake （FRSC） were investigated, and chemical composition and amino acid in vitro digestibility of RSC substrate fermented under optimal conditions were determined. Results： After 72 h of incubation at 34℃, a 76.89% decrease in GIs of RSC was obtained in solid medium containing 70% RSC, 30% wheat bran at optimal moisture content 60% （w/w）. Compared to unfermented RSC, trichloroacetic acid soluble protein （TCA-SP）, crude protein and ether extract contents of the FRSC were increased （P〈 0.05） 103.71, 23.02 and 23.54%, respectively. As expected, the contents of NDF and phytic acid declined （P〈 0.05） by 9.12 and 44.60%, respectively. Total amino acids （TAA） and essential amino acids （EAA） contents as well as AA in vitro digestibility of FRSC were improved significantly （P 〈 0.05）. Moreover, the enzyme activity of endoglucanase, xylanase, acid protease and phytase were increased （P 〈 0.05） during SSF. Conclusions： Our results indicate that the solid state fermentation offers an effective approach to improving the quality of proteins sources such as rapeseed cake.

Utilization of winery wastes for Trichoderma viride biocontrol agent production by solid state fermentation

Biocontrol agents are safe and environmental friendly alternatives for pesticides in agriculture application. Trichoderma viride WEBL0703 performed a high level of antagonistic activity toward a broad spectrum of phytopathogens and was determined as a biocontrol agent, which was produced by solid state fermentation using grape marc and wine lees. The maximum yield of T. viride conidia was up to 6.65 × 10^9 CFU/g initial dry substrate （IDS） after 10 d fermentation. As important enzymes for protecting plants from disease, chitinase, β-glucanase, and pectinase yields were 47.8 U/g IDS, 8.32 U/g IDS and 9.83 U/g IDS, respectively. These results show that it is feasible to convert winery wastes to a value-added and environmental friendly biocontrol agent.

In Vitro Probiotic Effect of Pseudostellaria heterophylla Fibrous Roots on Feed Bacillus subtilis and Preliminary Study on Its Solid Fermentation

Traditional Chinese medicine Pseudostellaria heterophylla fibrous roots have been widely studied and applied in non-antibiotic clinical breeding of livestock and poultry. In vitro probiotic effect of P. heterophylla fibrous roots extract on feed probiotics Bacillus subtilis BD-K010 was studied, and the feasibility of solid fermentation of P. heterophylla fibrous roots was preliminarily evaluated. For in vitro probiotic effect, the increased concentration of P. heterophylla fibrous roots extract dependently increased the total biomass of B. subtilis BD-K010;1.0% P. heterophylla fibrous roots extract received the best effect, and the final p H of 1.0% experimental group was closer to neutral. Meantime, B. subtilis BD-K010 with optimum concentration of P. heterophylla fibrous roots showed significantly higher in vitro antibacterial effect than the control group(P<0.01),and the antibacterial effects on Escherichia coli and Staphylococcus aureus were improved by 51.99% and 63.16%, but it was ineffective to Salmonella. For solid fermentation, the profile of substrate complex and appendage flocculent structure on substrate surface at the end of fermenta-tion in experimental groups added with B. subtilis BD-K010 and cellulase plus BD-K010 were more complex;the live bacteria number, polysaccharide content and saponin content at fermentation end-point in two experimental groups were extremely higher than those in the control group(P<0.01).P. heterophylla fibrous roots extract had good in vitro probiotic effect on B. subtilis BD-K010 and promoted its antibacterial effect, and it is feasible to use probiotics for solid fermentation of P. heterophylla fibrous roots and to improve effective components. It is of great significance to further de-velop and utilize P. heterophylla fibrous roots resources in modern animal husbandry.

Effect of selected fungi on the reduction of gossypol levels and nutritional value during solid substrate fermentation of cottonseed meal

The objective of this work was to investigate the effect of six individual strains of fungi on the reduction of gossypol levels and nutritional value during solid substrate fen＇aentation of cottonseed meal （CSM）. Six groups of disinfected CSM substrate were incubated for 48 h after inoculation with either of the fungi C. capsuligena ZD- 1, C. tropicalis ZD-3, S. cerevisae ZD-5, A. terricola ZD-6, A. oryzae ZD-7, or A. niger ZD-8. One not inoculated group （substrate） was used as a control. Levels of initial and final free gossypol （FG）, crude protein （CP）, amino acids （AA） and in vitro digestibility were assayed. The experiment was done in triplicate. The experimental results indicated that microbial fermentation could greatly decrease （P〈0.05） FG levels in CSM. The detoxification efficiency differed between the species of microorganisms applied. From the perspective of reducing CSM potential toxicity, C. tropicalis ZD-3 was most successful followed by S. cerevisae ZD-5 and A. niger ZD-8. They could reduce FG levels of CSM to 29.8, 63.07 and 81.50 mg/kg based on DM （dry matter）, respectively, and their detoxification rates were 94.57%, 88.51% and 85.16%, respectively. If crude protein, amino acids content and their in vitro digestibility were also taken into account, Aniger ZD-8 may be the best choice. The CP content of CSM substrate fermented by C. tropicalis ZD-3 and A. niger ZD-8 were improved by 10.76% and 22.24%; the TAA （total amino acids） contents were increased by 7.06% and 11.46%, and the EAA （essential amino acids） were raised by 7.77% and 12.64%, respectively. Especially, the levels of methionine, lysine and threonine were improved greatly （P〈0.05）. The in vitro CP digestibility of CSM fermented by C. tropicalis ZD-3 and A. niger ZD-8 was improved by 13.42% and 18.22%, the TAA were increased by 17.75% and 22.88%, and the EAA by 16.61% and 21.01%, respectively. In addition, the in vitro digestibility of methionine, lysine and threonine was also improved greatly （P〈0.05）.

Paddy Husk as Support for Solid State Fermentation to Produce Xylanase from Bacillus pumilus

To optimize culture conditions for xylanase production by solid state fermentation （SSF） using Bacillus pumilus, with paddy husk as support, solid medium contained 200 g of paddy husk with 800 mL of liquid fermentation medium [xylan, 20.0 g/L; peptone, 2.0 g/L; yeast extract, 2.5 g/L; K2HPO4, 2.5 g/L; KH2PO4, 1.0 g/L; NaCl, 0.1 g/L; （NH4）2SO4, 2.0 g/L, CaCl2-2H2O, 0.005 g/L; MgCl2.6H2O, 0.005 g/L; and FeCI3, 0.005 g/L] at pH 9.0 was applied. The highest xylanase activity （142.0 ±0.47 U/g DM] was obtained on the 6th day at 30℃ The optimized paddy husk to liquid fermentation medium ratio was 2：9, and the optimized culture temperature was 40℃. When commercial Birchwood xylan was replaced with different concentrations of corncob, xylanase production was maximized （224.2 U/g DM） in the medium with 150 g/L corncob. Xylanase production was increased by sucrose, fructose and arabinose, whereas reduced by glucose, galactose, lactose and amylose. When organic nitrogen sources were replaced with locally available nitrogen sources such as groundnut powder or sesame seedcake powder or coconut seedcake powder or soy meal powder, the highest xylanase production （290.7 U/g DM） was obtained in the medium with soy meal powder and 16.0 g/L of soy meal powder was the optimum （326.5±0.34 U/g DM）. Based on the optimization studies, B. pumilus produced 2.3 times higher xylanase activity. The medium cost was reduced from 2 458.3 to 178.3 SLR/kg and the total activity which could be obtained from 1 kg of the medium was increased from 48 624 to 220 253 Units.

Cellulase production by Aspergillus unguis in solid state fermentation

Lignocellulosic substrates are a good carbon source and provide rich growth media for a variety of microorganisms which prodLuce industrially important enzymes. Cellulases are a group of hydrolytic enzymes such as filter paperase (FPase), carboxymethyl cellulase(CMCase) andβ-glucosidase-responsible for release of sugars in the bioconversion of the lignocellulosic biomass into a variety of value-added products. This study examined cellulase production by a newly isolated Aspergillus unguis on individual lignocellulosic substrates in solid state fermentation (SSF). The maximum peak production of enzymes varied from one substrate to another, however,based on the next best solid support and local availability of groundnut fodder supported maximum enzyme yields compared with other solid supports used in this study.Groundnut fodder supported significant production of FPase (5.9 FPU/g of substrate), CMCase (1.1 U/g of substrate) andβ-glucosidase activity (6.5 U/g of substrate) in SSF. Considerable secretion of protein (27.0 mg/g of substrate) on groundnut fodder was recorded. Constant increment of protein content in groundnut fodder due to cultivation of A. unguis is an interesting observation and it has implications for the improvement of nutritive value of groundnut fodder for cattle.

Manganese peroxidase production from cassava residue by Phanerochaete chrysosporium in solid state fermentation and its decolorization of indigo carmine

Bioconversion of lignocellulosic wastes to higher value products through fungal fermentation has economic and ecological benefits. In this study, to develop an effective strategy for production of manganese peroxidase(Mn P)from cassava residue by Phanerochaete chrysosporium in solid state fermentation, the stimulators of Mn P production were screened and their concentrations were optimized by one-at-a-time experiment and Box–Behnken design. The maximum Mn P activity of 186.38 nkat·g-1dry mass of the sample was achieved after 6 days of fermentation with the supplement of 79.5 mmol·L-1·kg-1acetic acid, 3.21 ml·kg-1soybean oil, and 28.5 g·kg-1alkaline lignin, indicating that cassava residue is a promising substrate for Mn P production in solid state fermentation. Meanwhile, in vitro decolorization of indigo carmine by the crude Mn P was also carried out, attaining the ratio of 90.18% after 6 h of incubation. An oxidative mechanism of indigo carmine decolorization by Mn P was proposed based on the analysis of intermediate metabolites with ultra-high performance liquid chromatography and gas chromatography tandem mass spectrometry. Using the crude Mn P produced from cassava residue for indigo carmine decolorization gives an effective approach to treat dyeing effluents.

Mechanism of Solid State Fermentation in Reducing Free Gossypol in Cottonseed Meal and the Effects on the Growth of Broiler Chickens

[Objective] This study aims to reduce the free gossypol(FG) and improve utilization rate of cottonseed meal(CSM) by solid state fermentation(SSF). [Method]Bacillus subtilis GJ00141 and Saccharomyces cerevisiae GJ00079 were applied for the SSF and the optimal carbon source, nitrogen source, inorganic salt, moisture content, inoculum level, fermentation temperature, and fermentation time were investigated. The detoxifying effects of different products of GJ00141 were examined with gossypol as substrate. A total of 90 one-day-old broilers were randomized into group A [control, basal diet with 36% soybean meal(SM)], group B(basal diet with 18% SM and 18% CSM), and group C [basal diet with 18% SM and 18% fermented CSM(FCSM)] and thereby the influence of FCSM on the growth of broilers was explored. [Results] The maximum reduction rate(59%) of FG was achieved under the following fermentation conditions: solid medium composed of 96% CSM, 1%glucose, 1% ammonium sulfate, and 2% corn grits, 45% moisture content, 20%inoculum, fermentation at 30 °C for 60 h. Both the viable and inactivated cells of GJ00141 can reduce the content of gossypol, but the reduction rates were only about 20% after 72 h of incubation. Cellular contents and supernatant demonstrated strong detoxifying activity, which achieved the reduction rates of about 95% after 48 h, and the removal was free from the influence of proteinase K, heat, or EDTA. In the 42 d feeding experiment on broilers, the ratios of feed to gain were insignificantly different between the group C and group A. [Conclusion] This method achieved high rate of removing FG in CSM. The reason was the likelihood that the stable compounds in the cellular contents and supernatant of GJ00141 adsorb or bind to FG. Broilers grew well with the FCSM. Thus, it was an efficient detoxifying method for CSM.

Optimization of Solid State Fermentation Conditions Using a Mixture of Bean Curd Residue and Marc with Bacillus natto

[Objective] The aim was to optimize the appropriate solid state fermentation(SSF)conditions.[Method] The optimization of solid state fermentation using a mixture substrate of bean curd residue and the marc with Bacillus natto was developed.[Result] The best fermentation condition optimized by the test of single factor and the orthogonal design respectively was mixing ratio of bean curd residue to marc 2∶1,substrate pH value 6,fermentation temperature 39 ℃,inoculum volume 10% and fermentation time 48 h.Under this optimized fermentation condition,the content of crude fiber in the substrate decreased from 107.8 mg/g before SSF to 56.2 mg/g after SSF,and the degeneration rate of crude fiber was 47.87%.[Conclusion] The bean curd residue in its palatability was enormously improved by SSF with Bacillus natto strain,which could be expected to be widely used as raw material of health foodstuff.

Production of iturin A through glass column reactor (GCR) from soybean curd residue (okara) by <i>Bacillus subtilis</i>RB14-CS under solid state fermentation (SSF)

The present study was conducted with an aim to scale up the production of iturin A using soybean curd residue (okara). Iturin A was produced by indigenous bacterial strain Bacillus subtilis RB14-CS through glass column reactor (GCR) under solid state fermentation (SSF) was characterized. The enhanced iturin A production was observed with respect to enhanced substrate bed height when SSF was conducted in Erlenmeyer flask. To check the effect of substrate bed height on iturin A production under SSF of okara, GCR was introduced. Substrate bed height of 15 cm was suitable for iturin A production which was about 2700 mg/kg wet substrate. The observed iturin A production by the aerobic bacteria Bacillus subtilis in nearly anaerobic condition in such high substrate bed for SSF is a wonderful finding for development of SSF system in future.

Production of Amylase Enzyme through Solid State Fermentation by Aspergillus niger

Traditionally, coconut dregs will be used as animal feed after the extraction of coconut oil and coconut milk from the copra. This study was carried out to discover the commercial value of coconut dregs as a solid substrate in the production of amylase through solid state fermentation （SSF） since this agro-waste is fairly rich in nutrients, providing the necessary nutrients supplementation for better microbial activity to produce enzymes. In this study, amylase is to be produced from coconut dregs by Aspergillus niger through solid state fermentation （SSF）. Three parameters were covered, which are incubation time, initial moisture content of substrate and inoculum sizes. SSF was carried out by using incubator at 37 ~C to test for enzyme activity at these following parameters： incubation time： 24, 48, 72, 96 and 120 hours; substrate moisture content： 64, 66, 68, 70 and 72% （w/w）; inoculum sizes： 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 mL spore suspension （5.5 × 10^6 spores/mL）. Enzyme activities were measured through the estimation of liberated reducing sugars after the assay of amylase enzyme by using DNS （3, 5 dinitrosalicylic acid） method. Highest enzyme activities were obtained at these following parameters： incubation time： 72 hours （31.76 U/gds）; initial moisture content ofsubstrate： 66% （26.66 U / gds） and inoculum sizes： 2.0 mL （30.56 U/gds）.

Optimization of Solid-State Fermentation with Lactobacillus brevis and Aspergillus oryzae for Trypsin Inhibitor Degradation in Soybean Meal

The aim of the present study was to optimize trypsin inhibitor degradation in soybean meal by solid-state fermentation （SSF） with Lactobacillus brevis and Aspergillus oryzae, and to determine the effect of SSF on phytic acid, crude protein, crude fat, and amino acid profile. Response surface methodology （RSM） with Box-Behnken design was used to optimize SSF. The optimal conditions derived from RSM for L. brevis fermentation were： pH=5. 1; inoculum size=10%; duration=72 h; substrate to water ratio=1.5. The minimum content of trypsin inhibitors was 6.4 mg g^-1 dry matter. The optimal conditions derived from RSM for A. oryzae fermentation were： substrate to water ratio= 0.8 1; inoculum size=4%; duration=120 h. The minimum content of trypsin inhibitors was 1.6 mg g^-1 dry matter. Both L. brevis and A. oryzae decreased trypsin inhibitors dramatically （57.1 and 89.2% respectively）. L. brevis fermentation did not affect phytic acid （0.4%） and crude fat （5.2%） considerably, whereas A. oryzae fermentation degraded phytic acid （34.8%） and crude fat （22.0%） contents to a certain extent. Crude protein content was increased after both fermentation （6.4 and 12.9% for L. brevis and A. oryzae respectively）. Urease activity was reduced greatly （83.3 and 58.3% for L. brevis and A. oryzae respectively）. In conclusion, SSF with A. oryzae and L. brevis reduced trypsin inhibitor content and modified major macronutrients in soybean meal.

Multi-enzymes Production Studies in Single Tray Solid State Fermentation with Opened and Closed System

The robustness ofA. awamori and A. oryzae as enzyme producers is exploited in fungal fermentation on agricultural solid waste. High-level production of extracellular glucoamylase, protease, cellulase and xylanase has been achieved. Three different types of ＇waste＇ solids （wheat bran, soybean hulls and rapeseed meal） have been used in studies of solid state fermentation （SSF）. The enzymes could be produced in significant levels by continuously supplying oxygen （02） through the tray system known as ＂closed＂ and ＂opened＂ tray systems. A perforated tray system was developed in this study that permits direct access to 02. Testing the tray system with different perforated mesh aperture sizes in this study did not yield different results in growth performance of A. awamori and A. oryzae. A. awamori and A. oryzae can be very versatile in producing various enzymes with different substrates with different starch, protein, hemiceilulose and cellulose contents. These studies indicate that A. awamori is more suitable for the efficient production of multiple enzymes in the closed system including xylanase and cellulase, while the production of glucoamylase and protease is superior in the opened system. A. oryzae is more suitable for the efficient production of protease and cellulase in the closed system, while the production of protease is more favourable the opened system. A. awamori efficiently consumed starch in wheat bran medium and produced very high glucoamylase activity, and after that, the fungus efficiently produced other enzymes to degrade other complex nutrients such as protein, hemicellulose and cellulose. Meanwhile, A. oryzae efficiently consumed protein in rapeseed meal and produced very high protease activity. The ability of both filamentous fungi, to convert biomass through SSF bioconversion will have a great impact on food and agro-industry in every aspect of life from food and medicine to fuel.

Bidirectional solid fermentation using Trametes robiniophila Murr. For enhancing efficacy and reducing toxicity of rhubarb (Rheum palmatum L.)

Objective:To investigate the potential of bidirectional solid fermentation of rhubarb (Rheum palmatum L.) for reducing its toxicity and enhancing its medicinal efficacy.Methods:The fungus Trametes robiniophila Murr.was inoculated into rhubarb.The chemical ingredients as well as antioxidant,antibacterial,and anticancer activities of fermented and unfermented rhubarb extracts were then determined.Results:After fermentation,levels of anthraquinone glycosides (purgative ingredients) decreased significantly,while the level of anthraquinone aglycone increased.The level of gallic acid was also reduced after fermentation.Ethanol extract of rhubarb (0.8 mg/mL) exhibited DPPH-scavenging activity of 7.6% ± 0.8% while the blank control (0.8 mg/mL rhubarb)showed 31.3% ± 2.0% activity.Antibacterial activities in fermented samples were found to be enhanced compared with unfermented samples and anticancer activity was evident at concentrations of 2000 and 5000 μg/mL.Conclusion:Bidirectional solid fermentation appears to be an effective processing method that can be used to improve the efficacy and reduce the toxicity of rhubarb.

Production of chitinolytic enzymes with Trichoderma longibrachiatum IMI 92027 in solid substrate fermentation

Thirty Trichoderma strains representing 15 species within the genus have been screened for extracellular production of chitinolytic enzymes in solid substrate fermentation (SSF). T.longibrachiatum IMI 92027 (=ATCC 36838) gave the highest yield (5.0 IU/g dry matter of substrate) after 3 days of fermentation on wheat bran-crude chitin (9:1 mixture) medium. The optimum moisture content (66.7%), chitin content (20%), initial pH of the medium (2-5) and time course (5 d) of SSF were determined for strain IMI 92027. No significant effect of different N and P additives was found on the chitinase yield in wheat bran-chitin mixture medium. Cellulase, xylanase, alpha-amylase and beta-xylosidase activities were also detected. The pH and temperature optima of chitinase complex of T.longibrachiatum IMI 92027 was found to be at 4.5 and 55 ℃, respectively. The enzyme totally lost its activity at 70 ℃ in 5 min in the absence of the substrate but retained about 15% of its initial activity even at 70 ℃ after incubation of 60 min in the presence of SSF solids (residual substrate and fungal mycelium). Purification of protein extract from the SSF material revealed high chitinolytic activities between pI 5.9.-4.8 where N-acetyl-β-D-hexosaminidase and chitinase peaks have been found in the same pI range. Chitinase peaks could be described at least at four pI values: pI 5.9; 5.6; 5.3 and 4.8 while at least four main N-acetyl-β-D-hexosaminidase peaks could be separated at pI 6.0 and 5.1 and at more basic isoelectric points of 7.2 and 8.0. Two chitinases with 43.5 kDa and 30 kDa were purified at acidic isoelectric point.

Properties of crude laccase from Trametes versicolor produced by solid-substrate fermentation

A low-cost process for the production of laccases is necessary for a sustainable enzymatic wastewater treatment. Therefore, it is necessary to establish an easy and low-cost procedure for the production of laccase. In the present study the properties of crude laccase from Trametes versicolor produced by solid-substrate fermentation is investigated. The application of the enzyme for dye decolorization is also studied. Crude laccase from the studied culture established maximal activity at 45&#186;C. The enzyme retained over 90% of its activity in the temperature range 40- 47&#186;C and pH 4.5. The kinetic constants of the crude enzyme was also determined. In the presence of KCl, NaCl, CaCl2, MnSO4 and MgSO4, laccase demonstra- ted high stability—over 50% of its initial activity was still retained after 4-month incubation. Complete loss of enzymatic activity was observed in the presence of CuCl2, FeCl2, FeCl3 and NaN3 after 30 min of incubation. 100% decolorization by investigated crude laccase was completed in the case of Indigo Carmine for 4 h, Remazol Brilliant Blue R—for 6 h, Orange II— for 48 h and Congo Red—for 13 d.

The variation of two extracellular enzymes and soybean meal bitterness during solid-state fermentation of Bacillus subtilis

The debittering effect of extracellular enzymes from Bacillus subtilis ACCC 01746 was studied using soybean meal as a substrate for solid-state fermentation(SSF).Results showed that B.subtilis produces proteases and carboxypeptidase in the early stage of SSF(0–8 h).Proteases are dominant and can hydrolyze the soybean protein into long-chain peptides with mild bitterness.Carboxypeptidase production is dominant at 8–16 h SSF,at which point soybean protein is further hydrolyzed and bitterness is enhanced.The strain then produces additional carboxypeptidase after 16 h,and bitterness is reduced.We compared the amino acid composition of the hydrolysates from soybean protein isolates to that of the fermented liquid of SSF.In the hydrolysates from soybean protein isolates that exhibit strong bitterness,62.81%of amino acids are hydrophobic and occur in the form of peptides.In the fermented liquid from soybean meal,16.22%of amino acids are hydrophobic and are mainly present in the form of free amino acids.The bitterness of fermented soybean hydrolysate is reduced from 5 to 0 when fermented for 24 h,suggesting that B.subtilis can effectively reduce bitterness,possibly due to the carboxypeptidase.Enzyme analysis shows that B.subtilis excretes carboxypeptidase during growth.The amino acids phenylalanine,alanine,tyrosine,and leucine at the C-terminal of the soybean bitter peptides in hydrolysates are cleaved in the presence of carboxypeptidase,resulting in complete debitterness.

Consideration and development of anaerobic fermentation equipment on solid organic rejectamenta

This article, based on investigation and analysis, existed anaerobic fermentation equipment, with a view to the production of high-latitude area, pointed out the thought of exploiting efficient anaerobic fermentation equipment, including： the settting independent equipment of acidogenic phase and methanogenic phase; the applying conbination of AF and UASB in methanogenic phase; adopting efficient sludge inverse flowing equipment and the technique of flora enrichment, and efficient method of saving energy and thermal retardation; adopting autocontrol which could make the equipment run efficiently and stably.