Post about "fermentation"

Isolation, Identification and Liquid Culture of Antagonistic Actinomycetes to Penicillium Expansum

Patulin is a mycotoxin having ability in carcinogenesis, teratogenesis, mutagenesis and immunosupression. Penicillium expansum was proved to be the most important patulin-producing fungus in apple and apple products. Microorganisms that have ability in inhibiting Penicillium expansum have great potential in biocontrol of. P. expansium. The study aimed at searching antagonistic actinomycetes and evaluating their potential in biocontrol of P. expansium. Stability and conditions for production of the active components were also studied to get further information on practical application. Main contents and results of the study were listed as followings:(1)154 strains of actinomycetes were isolated from soil of apple orchard, kiwifruit orchard and vegetable orchard in Yangling Shaanxi province. Four strains of antagonistic actinomycetes named P50,C11,C16,C60 respectively were selected by prescreening for further screening, because they had high ability in inhibiting the growth of three strains of patulin-producing pecillium on the agar medium. Strain C16 was finally sreened out from four strains for further study on production and properties of active components because it showed the greatest inhibition ability to three patulin-producing P. expansium, and its average inhibitory diameter is 2.33cm in agar plate tests.(2)Actinomycetes C16 was classified and identified on the basis of morphologic and physi-biochemical characteristics and the analysis of 16 SrDNA sequence. It was identified as as a new species of the Genus of Micropolyspora, the Family of Micromonosporaceae, and the Order of Actinomycetale. It was named as Micropolyspora.C16 and patented as the code of CCTCC M207210.(3)The compositiona of media for cultivation seed of Actinomycetes CCTCC M207210 was optimized at 20.0 maltose g/L, 2.0 yeasty protein g/L, 1.0 K2HPO4 g/L, 1.0 MgSO4 g/L, and 1.0 NaCl g/L. Nutrients of the media for fermentation were optimized by using the central composite design. Results showed the highest value of cell growth was obtained at 2.70 maltose g/100mL,0.26 yeast protein g/100mL,0.17 K2HPO4 g/100mL,0.14 MgSO4 g/100mL,and 0.15 NaCL g/100mL. (4)Conditions for liquid cultivation of Actinomycetes CCTCC M207210 were optimized by using the Box-Behnken design. Response Surface Designs was used to analyze the data. The optimal conditions were obtained at inoculum’s amount of 13.5%(v/v), initial pH of 7.4, rotation speed of 180rpm, temperature of 27.6℃, and medium volume of 125mL in 250mL shake flask. Under the optimal conditions, the highest value of dry cell weight (DCW) was predicted as 6.27 g/L.( 5 ) In order to investigate the stability of active components for inhibiting patulin-producing Penicillium, the cell-free liquid culture of Actinomycetes CCTCC M207210 was tested on its ability in inhibiting the growth of P. expansium and patulin production in agar media after being treated for a period at different temperature, pH, and ultraviolet radiation.The cell-free liquid culture was also used in apple fruits and apple juice inoculated with P. expansium to test its potential in biological controller. The liquid culture was very stable at 28oC and pH 5.7 (the nature pH) but not stable at higher temperatures and when pH was too acidic or too alkaline. The inhibiting ability of the liquid culture declined by 39.5% when it was kept at 100oC for 30min and was completely destroyed when the treatment was prolonged to 60min. Comparatively, alkaline condition (pH8 to 10) showed higher inhibiting ability than acidic condition (pH2 to 4). The liquid culture lost the inhibiting ability when it was exposed to ultraviolet radiation for 90min. The liquid culture showed the highest inhibition of rotten ratio by 25% in apple fruit which was sprinked with the liquid culture 120h after inoculation of P. expansium. The patulin production was reduced by 90% when the liquid culture was added in apple juice at ratio of 40%(v/v). Therefore, the liquid culture had great potential in inhibiting the growth and patulin production of P. expansium.

Mechanism of Ethanol Tolerance Improvement of Free Yeast Cells in Wood-chips-packing System

Preliminary research revealed that the content of trehalose and the specific glucose consumption rate of free yeast cells were significantly improved by inoculating wood chips with yeast cells immobilized onto them. But the reason and mechanism of this phenomenon have not been explored.In this study, the ethanol tolerance of yeast cells was evaluated directly to examine the deduction in the preliminary research. It was found that the viability of free yeast cells in wood-chips-packing system was twice as high as that for no-packing system, which verified the previous deduction that the ethanol tolerance of free yeast cells in wood-chips-packing system was improved.Effects of inoculation and fermented broth as well as extract from the wood chips were further investigated to explore the mechanistic reason for this phenomenon. It was indicated that the increase of ethanol tolerance was not due to the difference of inoculation. The result demonstrated that the ethanol tolerance of the free yeast cells was improved by some compounds in the broth but the compound(s) was not from wood chips. Experiment results revealed that the ethanol tolerance of the yeast cells was improved by some compounds in the broth released from immobilized yeast cells, which might be related to some microorganism multi-cellular behavior.The effect of ethanol stress on the release of the compound(s) was further investigated. It was observed that the specific glucose consumption rates of yeast cells in the wood-chips-packing and no-packing systems were quite close to each other when the initial ethanol concentration in the medium was controlled at 0% or 4% (v/v). The specific glucose consumption rate of yeast cells in the wood-chips-packing system was about 10% higher than that in the no-packing system for an initial ethanol concentration of 8% (v/v). No significant difference was found in the viability of yeast cells between two systems under low ethanol condition (1.6%, v/v). These results revealed that the behavior that immobilized cells released some compounds to increase their ethanol tolerance is stress (ethanol)-dependent. This behavior of yeast cells might be an active response to the condition of ethanol stress.The effect of carrier on the release of the compound(s) was also investigated. The phenomenon of ethanol tolerance increasing for wood-chips-packing system was not observed when standard Ceramic Raschig Rings were used as carrier. The structure of wood chips was further analyzed using scanning electron microscope (SEM). It was suggested that the structure of yeast cell population might play an important role in the release of the compound(s) that can increase the ethanol tolerance of yeast cells. This feature is similar to those reported on microorganism multi-cellular behavior.Finally, the contents of trehalose and ergosterol (including free ergosterol and total ergosterol) and the plasma membrane ATPase activities of yeast cells in two systems were compared to investigate the mechanism of ethanol tolerance improvement. It was found that the contents of trehalose and the plasma membrane ATPase activities of yeast cells in two systems were close to each other at a low ethanol condition (1.6%, v/v). The contents of trehalose and ergosterol (including free ergosterol and total ergosterol) and the plasma membrane ATPase activities of yeast cells in wood-chips-packing system was higher than those in no-packing system at a high ethanol condition (11.6%, v/v). It was supposed that stress response pathways already opened was further activated by the compound(s) released from immobilized yeast cells, which caused the improvement of ethanol tolerance of free yeast cells in the system.

Improvement of Guanosine Producer Bacillus Subtilis JSIM-G518 and Studies on Optimization of Its Fermentation Conditions

Guanosine as known as 9-13-D-ribofuranosyl-guanine, is an important intermediate of foods and medicines. It can be used to synthesis 5′-disodium guanylate, disodium nucleotide and nucleoside antiviral drugs such as ribavirin, acyclovir. And it is the main material to manufacture Sodium Guanosine Triphosphate. As more and more enterprises are going to produce acyclovir, ribavirin and guanosine 5′-acid, the demand of guanosine is increasing quickly.With the goal of increasing the yield of guanosine, this study shows a mutant JSIM-GU-124-19 selected from Bacillus subtilis JSIM-G518, obtained from a production strain with protoplast mutation, which produced guanosine in a high yield after optimizing the fermentation condition. And the fed-batch fermentation and regulation of guanosine were studied. The main research and results are as follows:1. A fast and reliable method of obtaining protoplasts from JSIM-G518 which can produce guanosine is studied. The conditions of protoplast formation and the regeneration were determined through the analysis of enzyme concentration and temperature. The high-yield of protoplast is in 40 minute, 2.4 mg/mL (the final lysozyme concentration) at 36℃. The method of protoplasts mutagenesis is simple and effective, it can improve the production capacity and performance of bacteria in a short time. The paper electrophoresis display that fermentation both contain guanosine and guanine, so in order to obtain a high-yield guanosine strain we have to gain a mutant which lacks nucleoside hydrolyase through protoplasts mutagenesis. At the same time a mutant with SGr, Psir was obtained, the mutant could produce guanosine 24.0 g/L, which increased by 30% of the original strain.2. The optimizations of medium and fermentation conditions for the production of guanosine by the mutant JSIM-GU-124-19 were carred out on the basis of single factor experiments and response surface methodology. The optimal conditions were: pH 6.4, temperature 36℃, dissolved oxygen 40%, inoculation time 10 h. The optimized medium was: glucose 12.5%, yeast powder 1.4%, (NH4)2SO4 1.5%, MgSO4 0.5%, KH2PO4 0.4%, Sodium Glutamate (MSG) 1.0%, CaCl2 0.2%, soybean digest 4.0 mL/dL, corn steep liquor1.7 mL/dL, CaCO3 2.0%. The yield of guanosine was increased to 28.3 g/L after optimization.3. The fed-batch fermentation and regulation of guanosine were studied and the flow mode and concentration of Sodium Glutamate and Dioxane were established. The experiments show that adding 0.25%Sodium Glutamate can reduce the cost of raw materials. In 30 h adding the final concentration of 100 mg/L Dioxane can short the fermentation period.

Isolation and Characters Research of Wild Yeast Strains Which Produce Ethanol by Xylose-Fermenting

Strain No. 3 and No. 621 were two of 35 strains which isolated from nature. Their characters of morphological and fermentation of been systemic studied. Both strains have typical morphological characters of yeast, reproduction as budding and use familiar carbon resource, such as Glucose, lactose and so on. Strain No. 3 utilizes ammonium nitrogen and nitrate nitrogen. Strain No. 621 utilizes ammonium nitrogen but not nitrate nitrogen. Strain No. 3 grows at pH from 4.4 to 7.6, best of all between 6.6-7.0. Temperature ranged from 20℃-45℃, further between 28℃-30℃. Strain No. 3 grows at pH from 3.4 to 8.4, best of all between 5.2-6.4. Temperature ranged from 20℃-45℃, further between 28℃-30℃. Through 18S rDNA sequence analysis, strain No.3 is characterized as Candida intermedia and the other strain No. 621 shows highly identical 99.0% with Candida tropicalis.In conditions 28℃, 120 r/min, 72 h, strain 3 produced 6.480 g/L ethanol from 70 g/L xylose and 43.70 % theoretical production of ethanol from 30 g/L xylose. It can produce up to 21.225 g/L ethanol when incubation time prolong to 156 h from 80 g/L xylose. It also can ferment 130 g/L glucose produce 47.647 g/L ethanol and reach 76.90 % of theoretical ethanol production, respectively. Compared to CK, ethanol productivity can be improve 9.91 % when add 80 g/L xylose in three times as 30 g/L,20 g/L and 30 g/L, respectively. Glucose can be first utilized in the mixture sugar medium. Xylose-fermenting can be improve when glucose exist. Ethanol yield of mixture with 60 g/L xylose and 20 g/L glucose is 25 % more than the total yield by ferment them separate.In conditions 28℃, 120 r/min, 72 h , strain 621 produced 6.059 g/L ethanol from 90 g/L xylose and 35.08 % theoretical production of ethanol from 30 g/L xylose, and 15.593 g/L ethanol from 80 g/L xylose when incubation time prolong to 156 h. It also can ferment 110 g/L glucose produce 47.647 g/L ethanol in same conditions. Glucose can be first utilized from the mixture of xylose and glucose. Xylose-fermenting can be improve when glucose exist. Ethanol yield of mixture with 20 g/L xylose and 60 g/L glucose is 22 % more than the total yield by ferment them separate. Compared with add 80 g/L xylose in one time, ethanol productivity can be improve 11.00 % when add 80 g/L xylose in three times as 30 g/L, 20 g/L and 30 g/L, respectively. Results of Gas Chromatography analysis to the distilled products fermented from xylose, glucose or mixture of them, showed these two strains have high efficiency production of ethanol in all of them. It judged from curve direction that ethanol yield improved when aeration level in shake flask meliorate by increase of speed of shaker.Those two wild yeast strains were found to have tolerance to high osmotic pressure. Strain 3 can grow in liquid medium with up to 12 % NaCl, 6 % ethanol or 58 % glucose, while Strain 621 can grow in liquid medium with up to 16 % NaCl, or 4 % ethanol or 61 % glucose, respectively. 10 % NaCl effected the fermentation from xylose weakly.

Breeding of L-Glutamic Acid Hyper-producer and Optimization of Its Fermentation

In this paper, the fermentation principles of metabolism control were applied into original strain improvement of Corynebacterium melassecola GL-3 for the overproduction of L-glutamic acid. Then the compositions of medium and the conditions in fermentation were studied. The main research contents and results were as follows:Through examination the accuracy of the biological sensing method , combining the experimental specific circumstances, bio-sensing method for breeding strains detected L-glutamic in experiments was established. The reclaim of average bio-sensing of this method was 99.7%. This method was simple, rapid and economical.The L-glutamic producer was derived from the original strain Corynebacterium melassecola GL-3 by chemical and physical mutation methods, the plate screening with: High osmotic pressure, succinate as sole carbon sourse, NaF, SG, Gln. A strain N77-124(High osmotic pressure tolerance,Sucg,NaFr,SGr,Glnr) which could accumulate 110g/L L-glutamic acid.under un-optimization condition was acquired.The optimization of medium contents and fermentation conditions for N77-124 was conducted. The optimum seed medium conditions were pH 7.2 and the optimum medium volume was 30mL/250mL. The optimum fermentation medium contains glucose 161g/L, corn steep liquor 3.0g/L, K2HPO4·3H2O 2.0g/L, MgSO4·7H2O 0.8g/L,Urea 5.5. The optimum fermentation conditions were 500mL contains 20mL broth, initial pH7.5, inoculated time 8 h, culturing at 30±1℃on reciprocating shaker, shaking speed 100r/min, seed volume 10%, fermentation time 36h. After optimization, the production of L-glutamic was up to 114g/L with high conversion efficiency of 71%.N77-124 strains flask fed-batch fermentation of the preliminary was studied. The optimum initial glucose concentration was 80g/L. The lowest glueose concentration maintained was 10-20g/L. The optimum feeding glucose concentration was 600g/L. The control of fermentation temperature in this way: 0-10 h 34℃, 10-20 h 36℃, 20 h 38℃. The production of L-glutamic acid was up to 117g/L and conversion rate was up to 72% after 32 h.

Breeding of L-Histidine Producer and Optimization of Its Fermentation Conditions

According to the theory of metabolic control fermentation, the paper focuses on the breeding of L-Histidine hyper-producer WH1263, the suitable fermentation condition of shaking flask, the effect of calcium gluconate on L-Histidine fermentation. The main research contents and results are as follows:The methods of breeding L-Histidine producer from Corynebacterium glutamicum were decided based on the relationship with biosynthesis process of nucleotide and fed-back regulatory mechanism of L-Histidine biosynthesis. The L-Histidine producer was derived from the original strain Corynebacterium glutamicum CLW0506 by stepwise mutagenic treatments with ultraviolet (UV), N-methyl-N-nitro-N-nitrosoguanidine (NTG) and diethyl sulfate (DES). The objective mutant strain which absent AMP deaminase, IMP synthetase, IMP dehydrogenase and histidinase was obtained. The L-Histidine producing strain was also endued with other two genetic markers: 6-MPR, 5-FUR. The final mutant WH1263 could accumulate L-Histidine 8.50g/L which was about as 160% as the quantity produced by the parental strain.The WH1263 strain was passed down over ten generations for 72h fermentation the acid production was little changed. That proved the strain with a genetic stability characteristic.Using single factor, orthogonal experiment and response surface methods, Come to the best source of carbon is glucose, nitrogen source is ammonium sulfate, the best medium are (g/L): glucose 99.00, (NH4)2SO4 29.30, K2HPO4·3H2O 1.25, MgSO4·7H2O 0.50, CaCO3 20.00. The best concentrations of Zn2+, Mg2+, Fe2+ and Mn2+ are 2.2mmol/L, 1.8mmol/L, 1.2mmol/L and 0.27mmol/L. The initial pH7.0, vaccination of 6.7 percent, with volume of 15mL/250mL triangular flask, temperature 30°C, flask speed 100/min. The fermentation period is 72h. The mutant strain could accumulate L-Histidine 10.30g/L.By adding calcium gluconate to increase gluconic acid kinase activity, leading to the improvement of hexose monophosphate(HMP) shunt flux and its specific activity greatly. The mutant strain could accumulate L-Histidine 10.50g/L.

Breeding of L-Serine Producing Mutant and Study of Conditions in Fermentation

This paper is about L-Serine production by fermentation method which mainly investigated contents were breeding of L-Serine producing mutant and optimization of medium composition and fermentation conditions on L-Serine production in flask.The concentrations of L-Serine and glycine in broth were qualitatively and quantitatively determined with paper chromatography and spectrophotometer. The determination conditions of L-Serine and glycine were established. The relationship between the content of L-Serine in broth and the absorbency could be described by an expression. It was showed that the method has a high accuracy and precision in the determination of L-Serine and glycine. The method was also easy to operate and suitable for the screening of strains producing L-Serine.The L-Serine producing mutant ZC-8(D-SerR,GlyHR,MthR,SGR,Met-)was derived from Pseudomonas flava LJW-01(D-SerR,GlyR,MthR) seprated from the preserved mutant of the lab by combination treatment with diethylsulfate(DES) and N-methyl-N’-nitro- N-nitrosoguanidine (NTG). It could accumulate 6.2 g/L L-Serine.Compared with the original strain. ZC-8 has an improvement about 100% in the ability of accumulating L-Serine. It has a good stability of descendiblity of L-Serine producing.The effects of medium composition and fermentation conditions on L-Serine production in flask were considered. The seed medium compositions were optimized as follows(g/L): glucose 20, corn steep liquor 20, (NH4)2SO4 20, KH2PO4 1, MgSO4·7H2O 0.2. The optimal fermentation medium compositions were selected as follows(g/L):glycine 35, glucose 5, corn steep liquor 14, (NH4)2SO4 22, KH2PO4 1, MgSO4·7H2O 0.8, CaCO3 20. The optimum fermentation conditions were 250mL contains 25mL broth, original pH8.0~8.5, culturing at 30±1℃on reciprocating shaker, shaking speed 100r/min, seed volume 10%, fermentation time 72h. After optimization, the produc- tion of L-Serine was up to 9.82g/L.

Study on Improvement of 1, 3-Propanediol-producing Strains by Mutation and Its Fermentation

1,3-propanediol is acknowledged as one of six new petrochemical products currently in the world. Its main function is as an important monomer to synthesize a new type of polyester,polyether,polyurethane. 1,3-Propanediol is produced by two ways:chemical synthesis and microbial conversion. Producing 1,3-propanediol by microbial fermentation have many obvious advantages and become the focuses of research.Klebsiella sp. was used as the original strain for further research. A high 1,3-Propanediol-producing strain was obtained by UV and (0.5mg/mL)NTG-ultrasound (200W, 50kHz, 20min) inducing mutagenesis. In batch fermentation of mutant,the production of 1,3- propanediol was increased to 23.31 g/L (by 36.72%). The mutant strain showed genetic stability after 10 generations. The by-product, acetate, was increased, and ethanol was decreased, respectively. The amount of enzyme was not found changed significantly, but the activity of GDHt rises by 21% and the activity of PDOR also rise in a certain extent.The fermentation condition for Klebsiella sp. mutant producing 1,3-propanediol was preliminary optimized by single factor experiment. Different concentration of glycerol, yeast extract, KH2PO4 and other factors influencing the glycerol conversing to 1,3-propanediol was studied respectively. A further study on the fermentation medium composition was by orthogonal test. The optimum medium for mutant was as follows: glycerol 60g/L, yeast extract 6g/L, KH2PO4 3g/L、MgSO4·7H2O 1g/L. In flask fermentation, the production of 1,3- propanediol was increased to 27.03 g/L(by 9.92%).Effects on 1,3-propanediol production of Klebsiella sp. mutant by addition of reductant(VC, GSH, Cys, DTT)were studied.The yield of 1,3-propanediol can reach 29.77 g/L, 29.32 g/L, 29.87 g/L by adding 0.35 mmol/L DTT, 0.35 mmol/L Cys, 0.45mmol/L GSH singlely. They were all exceeded the value of control(27.01 g/L). The yield of 1,3-propanediol is 30.01 g/L(rise by 11.11%)by adding 0.25 mmol/L VC. Studying on the concentration variation of side products by adding VC, the results showed that the final concention of acetic acid, ethanol is increased by 3.77%, 3.35% accordingly. Experimental results also showed that addition of VC had an inhibitory effect on cell growth, but increased 1,3-propanediol production per cell considerably.Effects on 1,3-propanediol production of Klebsiella sp. by addition of ATP were studied. The result showed that addition of ATP had an inhibitory effect on cell growth. Adding 0.04 g/L ATP had a remarkable inhibitory effect on cell growth, the value of OD600 decreased by 26.5%. The yield of 1,3-propanediol is 30.05 g/L(rise by 11.26%)by adding 0.06 g/L ATP. Addition of ATP increased 1,3-propanediol production per cell and the conversion of side product acetate.Comparing to the control, the yield of acetic acid rised by 8.7% by adding 0.06 g/L ATP. Adding 0.06 g/L ATP to flasks at different fermentation stage(0h、4h、18h), the highest yield of 1,3-propanediol is 30.13 g/L(by 11.26%) by adding 0.06 g/L ATP at 4h. The value of 1,3-PD/OD is maximum (rise by 25.84%)by adding 0.06 g/L ATP at 0h, respectively.

Study on Production of Glucose Oligosaccharide by Biological Method

The objective of this work focused on using biological method to produce a glucose oligosaccharide, which provided new technology for the industrialization of glucose oligosaccharide.Firstly, dextran produced by Leuconostoc mesenteroides was stdutied. According to the growth curve of Leuconostoc mesenteroides and the time course of growth in shake flask, logarithmic growth phase of Leuconostoc mesenteroides was between 26 h and 36 h, and stationary phase was between 36 h and 60 h; after 26 h dextran was synthesised in fermentation broth. Fermentation experiments had been taken to determine the optimum fermentation liquid medium:sucrose 100 g/L, peptone 5.0 g/L, CaCO3 0.8 g/L, MgSO4 0.02 g/L, (NH42SO4 0.02 g/L; the optimum fermentation conditions in the shaker: temperature is 25℃, the inocating rate of actitivation solution is 5 %, the culture medium of fermentation liquid is 100/250 mL, the rotation speed of shaking table is 150 r/min, the starting pH of fermentation liquid is pH 7.5. At optimum medium and optimum conditions, the conversion rate of sucrose in shake flask and in fermentor was 62.58 % and 70.25 %, respectively.Secondly,the deproteinization and decoloration of fermentation liquid; the extraction and the precipitation of dextran were studied. The method of TCA was the best to remove proteins, 0.1 % TCA was used for deproteinization, the rate of deproteinization reached 81.5 % while the rate of dextran losing was only 10.2 %. The decoloration effect is better by the method of active carbon, the rate of decoloration reached 80.19 % while the rate of dextran losing was 19.24 %.Then three extraction methods’effects of the dextran had been compared, NaCl, KCl, NaOH. The results showed that the method of 0.6 mol/L KCl was the best for extraction at 60℃, the yield rate of dextran is 43.57 g/kg. The effect of ethanol precipitation dextran was examined , the results showed that 60 % ethanol terminal concentration was more effective to deposite dextran at 60℃, the yield rate of dextran is 41.28 g/kg.Thirdly, the production of glucose oligosaccharide by the pullulanase (Optimax EC 3.2.1.41) enzymolysising dextran was studied. Through the enzymolysis experiment, optimum conditions for enzymolysis dextran were: pH 4.4, the temperature 54℃, the reaction time 0.5 h, the enzyme concentration 2000 ASPU/g. The results showed that 94.11% dextran can be degradated to low molecular weight carbohydrate.Finally, glucose oligosaccharide’structure and nature were preliminary discussed.The highly effective liquid chromatography (HPLC) indicated that glucose oligosaccharide was 74.55% in enzymatic hydrolysate, with higher active ingredient than Ismalto-oligosaccharides IMO500 in sales.The infrared chromatograph indicated that the glucose oligosaccharide included alpha pyranose glucoside linkage. Through the glucose oligosaccharide relative viscosity’s determination, it was discovered that glucose oligosaccharide viscosity decreased while temperature increaseing; and increased while pH decreaseing; and in the pH 48 scope the viscosity increased faster; glucose oligosaccharide had the equivalent thermostability as well as other oligosaccharides. Through the glucose oligosaccharide relative solubility determination, it was discovered that the glucose oligosaccharide relative solubility was the biggest, reaching 82 % at 60℃; the solubility of product by the freeze-drying was the best, and the relative solubility reached 7985 %.

Hydrolysis of Jerusalem Artichoke by Inulinase Degrading Microorganism

In this dissertation , the optimium conditions for inulinase production and hydrolysis from Aspergillus niger SL-09 were carefully investigated. Flask liquid-state fermentation experiments were carried out. The results showed that the carbon source, nitrogen source, surfactants and the medium pH affected the production of inulinase production significantly. Under the optimum culture condition: 30℃, pH 6.0, 200 r/min, 3 d, the optimum component of the medium for enzyme production was (g/L): inulin 30, corn steep 20, sucrose ester 6, MnSO4·H2O 0.25. The highest inulinase activity reached 45.9 U/mL.The conditions for inulinase characterization were investigated. The following study shown that the optimized catalyze temperatures, substrate concentration and pH were 55℃, 40g/L and pH4.5, respectively.The favorable enzymolysis conditions were 50℃, 10% (v/v) whole liquid culture of Aspergillus niger. When 85.2 g/L total sugar of Jerusalem artichoke was used as the substrate, the highest hydrolytic rate of 99.6% was obtained at 12 h.Succinic acid fermentation from Jersulem artichoke using Aspergillus niger SL-09 and Actinobacillus succinogenes SF-09 was also studied. In the 5 L fermenter with enzymolysis syrup (53.5 g/L) as the substrate, the succinic acid concentration, productivity, and sugar conversion efficiency were 43.8 g/L,,1.22 g/(L·h) and 99.0% at 36 h, respectively.The cells of Aspergillus niger SL-09 were entrapped by barium alginate for inulin hydrolysis and treated by glutaraldehyde after immobilization. The activity yield of the immobilized cells was 49.39%. Various characteristics of immobilized cells were assessed.The optimal pH, temperature, inulin concentration were 4.0, 60℃,20 g/L, respectively. The conversion yield was above 70% throughout the 8 days, meanwhile, the storage stability and the operational stability were greatly improved after immobilization.