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1.
Biotransformation of steriodal saponins in Dioscorea zingiberensis C. H. Wright to diosgenin by Trichoderma harzianum 总被引:1,自引:0,他引:1
Lin Liu Yue-Sheng Dong Shan-Shan Qi Hui Wang Zhi-Long Xiu 《Applied microbiology and biotechnology》2010,85(4):933-940
Diosgenin is an important starting material in the steroidal hormone industry. Traditionally, diosgenin is mainly produced
by acid hydrolysis of Dioscorea zingiberensis C. H. Wright (DZW) tubers. This method yields numerous byproducts that can cause serious pollution. In this study, diosgenin
was obtained by biotransformation of steroidal saponins in DZW afforded by Trichoderma harzianum CGMCC 2979. The medium was optimized for maximum diosgenin production. The addition of phosphate buffer, surfactant Tween-85,
and Fe2+ increased the yield of diosgenin by 50.28%, 33.35%, and 22.07%, respectively. The optimum medium obtained by response surface
methodology was composed of 60 mmol l−1 phosphate buffer, 0.07% (w/v) Tween-85, and 0.93 mmol l−1 Fe2+. Under these conditions, a maximum diosgenin yield of 30.05 ± 0.59 mg g−1 was achieved, which was slightly higher than that obtained from traditional acid hydrolysis. By hydrolyzing the un-transformed
steroidal saponins after biotransformation, the total diosgenin yield increased by 35% compared to traditional method. Moreover,
chemical oxygen demand and residual reduced sugar in the wastewater produced by this integrated process were only 3.72% and
0.3%, respectively, that of the traditional acid hydrolysis method. 相似文献
2.
A β-glucosidase effectively releasing diosgenin from spirostanosides of Dioscorea zingiberensis C. H. Wright (DZW), named AfG, was purified from a strain of Aspergillus fumigates. The molecular weight of AfG was 113 kDa. Analysis of protein fragments by ESI-Q-TOF indicated that AfG was a β-glucosidase.
The circular dichroism spectrum suggested that the main secondary structure of AfG in Milli-Q water was α-helixes. Atomic
force microscopy revealed that it was a globular protein. AfG maintained high activity from pH 3.6 to 5.0 and from 50 to 90°C.
With the strong heat stability, AfG retained 55% of its original activity at 65°C for 120 h. AfG utilized muti-3-O-glycosides
of various steroidal saponins from DZW as substrate, such as trillin, diosgenin diglucoside, dioscin, deltonin and gracillin,
to yield diosgenin, suggesting the possibility of producing diosgenin from total saponins of DZW using a single enzyme. 相似文献
3.
J Hou J Xue C Wang L Liu D Zhang Z Wang W Li Y Zheng C Sung 《World journal of microbiology & biotechnology》2012,28(4):1807-1811
In the present investigation, we successfully employed a cell-free extract of Esteya vermicola CNU 120806 to convert ginsenoside Rg3 to Rh2. Three important factors including pH, temperature and substrate concentration
were optimized for the preparation of Rh2. The optimal condition was obtained as follows: 50°C, pH 5.0 and substrate concentration of 3 mg ml−1. The yield of conversion was up to 90.7%. In order to identify the specificity of the β-glucosidase activity of Esteya vermicola CNU 120806, ginsenoside Re (protopanaxatriol saponins) was treated under the same reaction system. Interestingly, no new
metabolite was generated, which elucidated that the enzymatic process only occurred by hydrolysis of the terminal glucopyranosyl
moieties at the C-3 carbon of ginsenoside Rg3. The crude enzyme extract can be used for commercial ginsenoside Rh2 preparation. 相似文献
4.
Feng B Hu W Ma BP Wang YZ Huang HZ Wang SQ Qian XH 《Applied microbiology and biotechnology》2007,76(6):1329-1338
It has been previously reported that a glucoamylase from Curvularia lunata is able to hydrolyze the terminal 1,2-linked rhamnosyl residues of sugar chains at C-3 position of steroidal saponins. In
this work, the enzyme was isolated and identified after isolation and purification by column chromatography including gel
filtration and ion-exchange chromatography. Analysis of protein fragments by MALDI-TOF/TOF™ proteomics Analyzer indicated
the enzyme to be 1,4-alpha-D-glucan glucohydrolase EC 3.2.1.3, GA and had considerable homology with the glucoamylase from Aspergillus oryzae. We first found that the glucoamylase was produced from C. lunata and was able to hydrolyze the terminal rhamnosyl of steroidal saponins. The enzyme had the general character of glucoamylase,
which hydrolyze starch. It had a molecular mass of 66 kDa and was optimally active at 50°C, pH 4, and specific activity of
12.34 U mg of total protein−1 under the conditions, using diosgenin-3-O-α-L-rhamnopyranosyl(1→4)-[α-L-rhamnopyranosyl (1→2)]-β-D-glucopyranoside (compound II) as the substrate. Furthermore, four kinds of commercial glucoamylases from Aspergillus niger were investigated in this work, and they had the similar activity in hydrolyzing terminal rhamnosyl residues of steroidal
saponin.
This project was supported by the National Natural Science Foundation of China (NSFC; 30572333). 相似文献
5.
《Process Biochemistry》2010,45(5):752-756
Diosgenin is an important starting material in the steroidal hormone industry. The yield of diosgenin obtained from the fermentation of Dioscorea zingibernsis C. H. Wright (DZW) by Trichoderma harzianum is higher than that typically obtained from acid hydrolysis. In this paper, the extraction of steroids in the culture broth was studied. A novel three-liquid-phase system (TLPS) consisted of petroleum ether, ethanol, ammonium sulphate and water was used to separate diosgenin and steroidal saponins in the culture broth. The partition behaviors of various steroidal saponins, diosgenin and glucose were investigated. From this, an optimized TLPS was obtained, which composed of 30% ethanol (w/w), 17% (NH4)2SO4 (w/w) and 40% (w/w) petroleum ether. In the optimized TLPS, almost all of the diosgenin was extracted into the top phase giving a recovery of 97.24%, whereas the steroidal saponins were mainly extracted into the middle phase, with recoveries of zingibernsis newsaponin, deltonin and diosgenin-diglucoside reaching almost 100%. The recoveries of trillin and diosgenin-triglucoside were 96.03% and 98.82%, respectively. Glucose tended to remain in the bottom phase, giving a recovery of 72.01%. The three-liquid-phase extraction (TLPE) successfully resulted in the simultaneous separation of diosgenin, untransformed steroidal saponins and glucose. 相似文献
6.
Vishal Gupta Manoj Kumar Puja Kumari C. R. K. Reddy Bhavanath Jha 《Journal of applied phycology》2011,23(2):209-218
This study reports on the optimization of protoplast yield from two important tropical agarophytes Gracilaria dura and Gracilaria verrucosa using different cell-wall-degrading enzymes obtained from commercial sources. The conditions for achieving the highest protoplast
yield was investigated by optimizing key parameters such as enzyme combinations and their concentrations, duration of enzyme
treatment, enzyme pH, mannitol concentration, and temperature. The significance of each key parameter was also further validated
using the statistical central composite design. The enzyme composition with 4% cellulase Onozuka R-10, 2% macerozyme R-10,
0.5% pectolyase, and 100 U agarase, 0.4 M mannitol in seawater (30‰) adjusted to pH 7.5 produced the highest protoplast yields
of 3.7 ± 0.7 × 106 cells g−1 fresh wt for G. dura and 1.2 ± 0.78 × 106 cells g−1 fresh wt for G. verrucosa when incubated at 25°C for 4–6 h duration. The young growing tips maximally released the protoplasts having a size of 7–15 μm
in G. dura and 15–25 μm in G. verrucosa, mostly from epidermal and upper cortical regions. A few large-size protoplasts of 25–35 μm, presumably from cortical region,
were also observed in G. verrucosa. 相似文献
7.
Based on the response surface methodology, an effective microbial system for diosgenin production from enzymatic pretreated
Dioscorea zingiberensis tubers with Trichoderma reesei was studied. The fermentation medium was optimized with central composite design (35) depended on Plackett–Burmann design which identified significant impacts of peptone, K2HPO4 and Tween 80 on diosgenin yield. The effects of different fermentation conditions on diosgenin production were also studied.
Four parameters, i.e. incubation period, temperature, initial pH and substrate concentration were optimized using 45 central composite design. The highest diosgenin yield of 90.57% was achieved with 2.67% (w/v) of peptone, 0.29% (w/v) of
K2HPO4, 0.73% (w/v) of Tween 80 and 9.77% (w/v) of substrate, under the condition of pH 5.8, temperature 30 °C. The idealized incubation
time was 6.5 days. After optimization, the product yield increased by 33.70% as compared to 67.74 ± 1.54% of diosgenin yield
in not optimized condition. Scale-up fermentation was carried out in a 5.0 l bioreactor, maximum diosgenin yield of 90.17 ± 3.12%
was obtained at an aeration of 0.80 vvm and an agitation rate of 300 rpm. The proposed microbial system is clean and effective
for diosgenin production and thus more environmentally acceptable than the traditional acid hydrolysis. 相似文献
8.
Production of diosgenin from Dioscorea zingiberensis tubers through enzymatic saccharification and microbial transformation 总被引:1,自引:0,他引:1
Yu-Ling Zhu Wen Huang Jin-Ren Ni Wei Liu Hui Li 《Applied microbiology and biotechnology》2010,85(5):1409-1416
In order to develop a clean and effective approach for producing the valuable drug diosgenin from Dioscorea zingiberensis tubers, two successive processes, enzymatic saccharification and microbial transformation, were used. With enzymatic saccharification,
98.0% of starch was excluded from the raw herb, releasing saponins from the network structure of starch. Subsequently, the
treated tubers were fermented with Trichoderma reesei under optimal conditions for 156 h. During microbial transformation, glycosidic bonds, which link β-d-glucose or α-l-rhamnose with aglycone at the C-3 position in saponins, were broken down effectively to give a diosgenin yield of 90.6 ± 2.45%,
42.4% higher than that obtained from bioconversion of raw tubers directly. Scaled up fermentation was conducted in a 5.0-l
bioreactor and gave a diosgenin yield of 91.2 ± 3.21%. This is the first report on the preparation of diosgenin from herbs
through microbial transformation as well as utilizing other available components in the raw material, providing an environmentally
friendly alternative to diosgenin production. 相似文献
9.
A bifunctional cellulase–xylanase of a new Chryseobacterium strain isolated from the dung of a straw‐fed cattle 下载免费PDF全文
Hao Tan Renyun Miao Tianhai Liu Lufang Yang Yumin Yang Chunxiu Chen Jianrong Lei Yuhui Li Jiabei He Qun Sun Weihong Peng Bingcheng Gan Zhongqian Huang 《Microbial biotechnology》2018,11(2):381-398
A new cellulolytic strain of Chryseobacterium genus was screened from the dung of a cattle fed with cereal straw. A putative cellulase gene (cbGH5) belonging to glycoside hydrolase family 5 subfamily 46 (GH5_46) was identified and cloned by degenerate PCR plus genome walking. The CbGH5 protein was overexpressed in Pichia pastoris, purified and characterized. It is the first bifunctional cellulase–xylanase reported in GH5_46 as well as in Chryseobacterium genus. The enzyme showed an endoglucanase activity on carboxymethylcellulose of 3237 μmol min?1 mg?1 at pH 9, 90 °C and a xylanase activity on birchwood xylan of 1793 μmol min?1 mg?1 at pH 8, 90 °C. The activity level and thermophilicity are in the front rank of all the known cellulases and xylanases. Core hydrophobicity had a positive effect on the thermophilicity of this enzyme. When similar quantity of enzymatic activity units was applied on the straws of wheat, rice, corn and oilseed rape, CbGH5 could obtain 3.5–5.0× glucose and 1.2–1.8× xylose than a mixed commercial cellulase plus xylanase of Novozymes. When applied on spent mushroom substrates made from the four straws, CbGH5 could obtain 9.2–15.7× glucose and 3.5–4.3× xylose than the mixed Novozymes cellulase+xylanase. The results suggest that CbGH5 could be a promising candidate for industrial lignocellulosic biomass conversion. 相似文献
10.
Introduction – Asparagus officinalis L. has several biological activities including antifungal, antiviral and antitumoral activities due to the steroidal saponins. Normally diosgenin and sarsasapogenin are analysed separately by thin‐layer chromatography or high‐performance liquid chromatography (HPLC‐UV or HPLC‐ELSD), which is time‐consuming and expensive, so we need to find a rapid solution to this problem. Objective – To develop a sensitive, rapid and validated TLC method for simultaneous detection and quantification of diosgenin and sarsasapogenin. Methodology – Samples were prepared by extraction of A. officinalis with 70% aqueous ethanol to get steroidal saponins, and then hydrolysed using 36 mL 2 m hydrochloric acid for 3 h. The hydrolysis product was extracted with chloroform, and then analysed by TLC, the results of which were verified by HPLC and HPLC‐MS. Results – The retention factor (Rf) of diosgenin and sarsasapogenin on TLC plate were 0.49 and 0.6, respectively. After calculation from the regression equation of the standard curve, the contents of diosgenin and sarsasapogenin in the A. officinalis extract were 0.27–0.46 and 0.11–0.32%, respectively. Conclusion – The study showed that thin‐layer chromatography can be applied for the determination of diosgenin and sarsasapogenin in the oldest tissue of A. officinalis, and also can be conducted for screening of sapogenin in other plant or extracts. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
11.
《Biochemical Engineering Journal》2010,48(1-3):80-86
In order to enhance the thermostability and efficiency of cellulase in the extraction of diosgenin from Dioscorea zingiberensis C.H. Wright, we applied polyethylene glycol (PEG) (400, 1000, 2000, and 4000) to modify cellulase. The modified cellulase, α-amylase and β-glycosidase were used to hydrolyze the material. The results show that the thermostability of modified cellulase is better than that of natural cellulase, the optimum pH value and temperature of modified cellulase are wider than that of natural cellulase, the activity of cellulase modified by activated PEG2000 is higher than that of cellulase modified by other modifiers, and its remaining activity is 58% of its initial value. With this technique, the purity of the product reaches 96%, the melting point is 201–204 °C, the yield rate and the extraction rate of the diosgenin reaches 2.80% and 96.6%, respectively. IR spectra and 1H NMR spectroscopy were used to confirm the structure of the product. 相似文献
12.
Pathways and kinetics analysis of biotransformation of Dioscorea zingiberensis by Aspergillus oryzae
《Biochemical Engineering Journal》2011,53(2-3):123-130
In this paper, the pathways and kinetics for the production of diosgenin via biotransformation of Dioscorea zingiberensis C.H. Wright by Aspergillus oryzae CICC 2436 were analyzed. After 120 h of biotransformation at 30 °C, the concentration of diosgenin in the culture reached 36.87 ± 1.27 μmol/g raw herb, which was 21.2 times its initial concentration. A number of steroidal compounds were also isolated as minor products from the biotransformation, and one of these was identified as a novel compound named 3-O-β-d-glucopyranosyl (1 → 3) – β-d-glucopyranosyl (1 → 4) – β-d-glucopyranosyl-diosgenin (diosgenin-triglucoside). The biotransformation consisted of two stages: the release of steroids from the herb (accompanied by fungal growth) and hydrolysis of the steroids by glycosidases. Kinetic analysis and mathematical modelling showed that the process of biotransformation could be described by first-order kinetics under the condition of high Km/[S] values. It consisted of a cascade of consecutive and parallel reactions involving three kinds of enzymes, five steroid saponins and their sapogenin. The main hydrolysis reactions that led to the production of diosgenin were also discussed. 相似文献
13.
In-Hye Park Jie Chang Yong-Seok Lee Shu-Jun Fang Yong-Lark Choi 《The protein journal》2012,31(3):238-245
The bacterial strain Paenibacillus xylanilyticus KJ-03 was isolated from a sample of soil used for cultivating Amorphophallus konjac. The cellulase gene, cel5A was cloned using fosmid library and expressed in Escherichia coli BL21 (trxB). The cel5A gene consists of a 1,743 bp open reading frame and encodes 581 amino acids of a protein. Cel5A contains N-terminal signal
peptide, a catalytic domain of glycosyl hydrolase family 5, and DUF291 domain with unknown function. The recombinant cellulase
was purified by Ni-affinity chromatography. The cellulase activity of Cel5A was detected in clear band with a molecular weight
of 64 kDa by zymogram active staining. The maximum activity of the purified enzyme was displayed at a temperature of 40 °C
and pH 6.0 when carboxymethyl cellulose was used as a substrate. It has 44% of its maximum activity at 70 °C and retained
66% of its original activity at 45 °C for 1 h. The purified cellulase hydrolyzed avicel, CMC, filter paper, xylan, and 4-methylumbelliferyl
β-d-cellobiose, but no activity was detected against p-nitrophenyl β-d-glucoside. The end products of the hydrolysis of cellotetraose and cellopentaose by Cel5A were detected by thin layer chromatography,
while enzyme did not hydrolyze cellobiose and cellotriose. 相似文献
14.
《Process Biochemistry》2010,45(8):1383-1392
It is known that the sugar chain linked to steroidal frame plays an important role in physiological and pharmacological activities. In the previous research, we found and confirmed that the terminal C3-O-α-1,2-rhamnosyl moiety linked to the C-3 of steroidal saponin is the key group of platelet aggregation and cytotoxicity. In order to make a complete approach for the structure–activity relationship, we have tried to find the specific enzymes modifying the structure of C3-sugar chain. In the present paper, we describe a novel enzyme from, Klerzyme-150 (K-150), which is specifically capable of hydrolyzing the α-1,4-glycosyl residues at C-3 postion of steroidal saponins. 15 steroidal saponins with different monosaccharides at C3-sugar chains were chosen as substrates to investigate the substrate specificity of K-150. The results showed, based on TLC, HPLC and spectra data analyses, that all products were determined as secondary saponins with the α-1, 4-glycosyl residues removed, which indicated that the enzyme exhibited strict regioselectivity and stereoselectivity. The novel enzyme was purified from K-150 to apparent homogeneity and its structure was identified as rhamnogalacturonan lyase A (Rgl A). The molecular mass of the purified enzyme was 52.08 kDa. 相似文献
15.
β-Glucosidase is frequently used to supplement cellulase preparations for hydrolysis of cellulosic and lignocellulosic substrates
in order to accelerate the conversion of cellobiose to glucose. Typically, commercial cellulase preparations are deficient
in this enzyme and accumulation of cellobiose leads to product inhibition. This study evaluates the potential for recycling
β-glucosidase by immobilization on a methacrylamide polymer carrier, Eupergit C. The immobilized β-glucosidase had improved
stability at 65 °C, relative to the free enzyme, while the profile of activity versus pH was unchanged. Immobilization resulted
in an increase in the apparent Km from 1.1 to 11 mm and an increase in Vmax from 296 to 2430 μmol mg−1 min−1. The effect of immobilized β-glucosidase on the hydrolysis of cellulosic and lignocellulosic substrates was comparable to
that of the free enzyme when used at the same level of protein. Operational stability of the immobilized β-glucosidase was
demonstrated during six rounds of lignocellulose hydrolysis.
Received 22 August 2005; Revisions requested 20 September 2005; Revisions received 8 November 2005; Accepted 10 November 2005 相似文献
16.
In this study, the cellulase gene celD from Clostridium thermocellum was cloned into expression vectors pET-20b(+) and pHsh. While high expression can be achieved by means of both these expression
systems, only the pHsh expression system gives soluble proteins. By weakening the mRNA secondary structure and replacing the
rare codons for the N-terminal amino acids of the target protein, the expression level of CelD was increased from 4.1 ± 0.3 to 6.4 ± 0.4 U ml−1 in LB medium. Recombinant CelD was purified by heat treatment followed by Ni–NTA affinity. The purified CelD exhibited the
highest activity at pH 5.4 and 60°C, and retained more than 50% activity after incubation at 70°C for 1 h. The cellulase activity
of CelD was significantly enhanced by Ca2+ but inhibited by EDTA. The favorable properties of CelD offer the potential for genetic modification of strains for biomass
degradation. Presently, one of the major bottlenecks for industrial cellulase users is the high cost of enzyme production.
The high level expression of soluble enzymes from the pHsh expression system offers a novel approach for the production of
cellulases to be used in various agro-industrial processes such as chemical, food and textile. 相似文献
17.
Shakuntala Ghorai Sumana Mukherjee Suman Khowala 《Biotechnology and Bioprocess Engineering》2011,16(2):297-304
Increased production, secretion, and activity of β-glucosidase in the filamentous fungus Termitomyces clypeatus was achieved in presence of the glycosylation inhibitor 2-deoxy-d-glucose (0.05%, w/v) during submerged fermentation. Enzyme activity increased to 163 U/mL by adding mannose (2 mg/mL) to
the medium. Such a high enzyme activity has not been achieved without mutation or genetic manipulation. The Km and Vmax of the enzyme in culture medium were determined to be 0.092 mM and 35.54 U/mg, respectively, with p-nitrophenyl β-d-glucopyranoside as substrate, confirming its high catalytic activity. The enzyme displayed optimum activity at pH 5.4 and
45°C. The enzyme was fairly stable between acidic to alkaline pH and retained about 75 ∼ 65% residual activities between pH
4 and 10.6 and demonstrated full activity at 45°C for 3 days. The enzyme was also stable in the presence of Zn2+ and Mg2+ and 80% of the residual activity was observed in the presence of Mn2+, Ca2+, K+, Cu2+, EDTA, and sodium azide. Around 70% of the activity was retained in the presence of 2 M guanidium HCl and 3 M urea, whereas
the activity was 5 and 2 times higher in the presence of 4 mM beta-mercaptoethanol and 50 mM DTT, respectively. The enzyme
obtained from the culture filtrate showed potential cellulose saccharifying ability which increased further when supplemented
with commercial cellulase. Thus, this enzyme could be used without any additional downstream processing for commercial cellulase
preparation and production of bioethanol or for other biotechnological applications. 相似文献
18.
Dan Zhang Yanqing Luo Shaohua Chu Yuee Zhi Bin Wang 《Preparative biochemistry & biotechnology》2016,46(6):575-585
Biological pretreatment of rice straw and production of reducing sugars by hydrolysis of bio-pretreated material with Streptomyces griseorubens JSD-1 was investigated. After 10 days of incubation, various chemical compositions of inoculated rice straw were degraded and used for further enzymatic hydrolysis studies. The production of cellulolytic enzyme by S. griseorubens JSD-1 favored the conversion of cellulose to reducing sugars. The culture medium for cellulolytic enzyme production by using agro-industrial wastes was optimized through response surface methodology. According to the response surface analysis, the concentrations of 11.13, 20.34, 4.61, and 2.85 g L?1 for rice straw, wheat bran, peptone, and CaCO3, respectively, were found to be optimum for cellulase and xylanase production. Then the hydrolyzed spent Streptomyces cells were used as a nitrogen source and the maximum filter paper cellulase, carboxymethylcellulase, and xylanase activities of 25.79, 78.91, and 269.53 U mL?1 were achieved. The crude cellulase produced by S. griseorubens JSD-1 was subsequently used for the hydrolysis of bio-pretreated rice straw, and the optimum saccharification efficiency of 88.13% was obtained, indicating that the crude enzyme might be used instead of commercial cellulase during a saccharification process. These results give a basis for further study of bioethanol production from agricultural cellulosic waste. 相似文献
19.
Mark S. Ou Lonnie O. Ingram K. T. Shanmugam 《Journal of industrial microbiology & biotechnology》2011,38(5):599-605
Lactic acid is used as an additive in foods, pharmaceuticals, and cosmetics, and is also an industrial chemical. Optically
pure lactic acid is increasingly used as a renewable bio-based product to replace petroleum-based plastics. However, current
production of lactic acid depends on carbohydrate feedstocks that have alternate uses as foods. The use of non-food feedstocks
by current commercial biocatalysts is limited by inefficient pathways for pentose utilization. B. coagulans strain 36D1 is a thermotolerant bacterium that can grow and efficiently ferment pentoses using the pentose-phosphate pathway
and all other sugar constituents of lignocellulosic biomass at 50°C and pH 5.0, conditions that also favor simultaneous enzymatic
saccharification and fermentation (SSF) of cellulose. Using this bacterial biocatalyst, high levels (150–180 g l−1) of lactic acid were produced from xylose and glucose with minimal by-products in mineral salts medium. In a fed-batch SSF
of crystalline cellulose with fungal enzymes and B. coagulans, lactic acid titer was 80 g l−1 and the yield was close to 80%. These results demonstrate that B. coagulans can effectively ferment non-food carbohydrates from lignocellulose to l(+)-lactic acid at sufficient concentrations for commercial application. The high temperature fermentation of pentoses and
hexoses to lactic acid by B. coagulans has these additional advantages: reduction in cellulase loading in SSF of cellulose with a decrease in enzyme cost in the
process and a reduction in contamination of large-scale fermentations. 相似文献
20.
He Jun Yu Bing Zhang Keying Ding Xuemei Chen Daiwen 《Indian journal of microbiology》2009,49(2):188-195
The strain of Trichoderma reesei Rut C-30 was subjected to mutation after treatment with N-methyl-N′-nitro-N-nitrosoguanidine (NG) for 6 h followed by UV irradiation for 15 min. Successive mutants showed enhanced cellulase production,
clear hydrolysis zone and rapid growth on Avicel-containing plate. Particularly, the mutant NU-6 showed approximately two-fold
increases in activity of both FPA and CMCase in shake flask culture when grown on basal medium containing peptone (1%) and
wheat bran (1%). The enzyme production was further optimized using eight different media. When a mixture of lactose and yeast
cream was used as cellulase inducer, the mutant NU-6 yielded the highest enzyme and cell production with a FPase activity
of 6.2 U ml−1, a CMCase activity of 54.2 U ml−1, a β-glucosidase activity of 0.39 U ml−1, and a fungal biomass of 12.6 mg ml−1. It deserved noting that the mutant NU-6 also secreted large amounts of xylanases (291.3 U ml−1). These results suggested that NU-6 should be an attractive producer for both cellulose and xylanase production. 相似文献