scholarly journals Xylanase activity from Cellulomonas flavigena extracts as affected by temperature and its degradation under in vitro ruminal conditions

2011 ◽  
Vol 5 (8) ◽  
pp. 961-964 ◽  
Author(s):  
A Hernaacute ndez P ◽  
R Baacute rcena J ◽  
D Mendoza G ◽  
C Montes M ◽  
S Gonzaacute lez S ◽  
...  
Keyword(s):  
Xylanase Activity ◽  
Cellulomonas Flavigena

scholarly journals Stability of feed enzymes in physiological conditions assayed by in vitro methods

1993 ◽  
Vol 2 (2) ◽  
pp. 125-132
Author(s):  
Johan Inborr ◽  
Anne Grönlund
Keyword(s):  
Proteolytic Enzymes ◽  
Wheat Gluten ◽  
Xylanase Activity ◽  
Initial Value ◽  
Enzyme Preparations ◽  
Neutral Ph ◽  
Feed Enzymes ◽  
The Stability ◽  
Upper Gastrointestinal

A series of in vitro incubations were carried out to investigate the stability of two enzyme preparations in conditions similar to those in the upper gastrointestinal tract of monogastric animals. The two enzyme products, one crude xylanase from Trichoderma longibrachiatum (Multifekt K) and the other a specifically manufactured feed enzyme (Avizyme SX®), were subjected to incubations at low and neutral pH with and without proteolytic enzymes (pepsin and pancreatin). Wheat gluten was employed together with the crude xylanase to investigate its potential as a stabilising agent. Due to the buffering effect of Avizyme SX®, incubations were carried out with (pH 2.5) and without (pH 3.2) addition of either citric or hydrochloric acid. Incubation of the crude xylanase at low pH followed by incubation at neutral pH resulted in negligible loss of xylanase activity whereas β-xylosidase recovery fell to 57 per cent of the initial value (P

Partial Characterization of the Streptomyces lividans xlnB Promoter and Its Use for Expression of a Thermostable Xylanase from Thermotoga maritima

1998 ◽  
Vol 64 (11) ◽  
pp. 4217-4225 ◽  
Author(s):  
Chih-Cheng Chen ◽  
Janet Westpheling
Keyword(s):  
Genomic Library ◽  
Glucose Repression ◽  
Signal Sequence ◽  
Thermotoga Maritima ◽  
Protein Localization ◽  
Xylanase Activity ◽  
Upstream Region ◽  
Supernatant Fraction ◽  
Thermostable Xylanase

ABSTRACT Xylanase activity assays were used to screen a Streptomyces coelicolor genomic library in Escherichia coli, and a xylanase gene that is 99% identical to the xylanase B gene (xlnB) of S. lividans (GenBank accession no. M64552 ) was identified. The promoter region of this gene was identified by using a transcriptional fusion between the upstream region of the S. coelicolor xlnB gene and thexylE reporter gene. Transcription from the xlnBpromoter was found to be induced by xylan and repressed by glucose. A single apparent transcription start site was identified by both primer extension analysis and in vitro run off transcription assays. Analysis of deletions of the promoter identified a region required for glucose repression. By using the transcriptional and protein localization signals of the Streptomyces xlnB gene, an in-frame translational fusion between the end of the xlnB signal sequence and the ATG of the Thermotoga maritima xynA gene was constructed. The xynA gene encodes a thermostable xylanase that has been demonstrated to be useful in the bleaching of Kraft pulp. The xlnB-xynA gene fusion was expressed inStreptomyces, and the activity of the protein produced was thermostable and was localized to the supernatant fraction of harvested cells.

scholarly journals Effect of nitrate and its reduction products on the growth and activity of the rumen microbial population

1988 ◽  
Vol 59 (2) ◽  
pp. 301-313 ◽  
Author(s):  
J. P. Marais ◽  
Joha J. Therion ◽  
R. I. Mackie ◽  
A. Kistner ◽  
C. Dennison
Keyword(s):  
Redox Potential ◽  
Volatile Fatty Acids ◽  
Microbial Population ◽  
Clinical Symptoms ◽  
Xylanase Activity ◽  
In Vitro Digestibility ◽  
Rumen Bacteria ◽  
Cellulolytic Bacteria ◽  
Rumen Microbes

1. The nature of the digestion-inhibiting substance in Kikuyu grass (Pennisetum clandestinum, Hochst), containing high levels of nitrate, was investigated using in vitro digestibility techniques.2. Nitrite, which accumulated during the reduction of nitrate to ammonia, seemed to be the primary factor reducing digestibility. Nitrate and ammonia did not affect digestion in vitro.3. Nitrite caused a reduction in the cellulolytic, xylanolytic and total microbial population, with a concomitant reduction in cellulase and xylanase activity of the digesta.4. The mode of action of nitrite on rumen microbial growth was investigated.5. The possibility that the growth of cellulolytic rumen microbes was depressed by a reduction in concentration of essential branched-chain volatile fatty acids by nitrite was discounted.6. Although nitrite caused a marked increase in the redox potential, due to its oxidizing properties, the more-positive redox potential did not reduce the digestibility of the grass.7. The growth of three of the four major cellulolytic bacteria commonly found in the rumen was severely depressed by nitrite, while some rumen bacteria were relatively insensitive to nitrite.8. Growth inhibition seemed to depend primarily on the extent to which these microbes derive their energy from electron-transport-mediated processes.9. It was suggested that, due to the sensitivity of some rumen bacteria to nitrite, digestibility and therefore animal performance could be affected long before clinical symptoms of nitrite toxicity become apparent.

scholarly journals Statistical optimization of xylanase production, using different agricultural wastes by Aspergillus oryzae MN894021, as a biological control of faba bean root diseases

2020 ◽  
Vol 30 (1) ◽  
Author(s):  
Sherien M. M. Atalla ◽  
Nehad E. Ahmed ◽  
Hassan M. Awad ◽  
Nadia G. El Gamal ◽  
Aliaa R. El Shamy
Keyword(s):  
Biological Control ◽  
Antifungal Activity ◽  
Rice Straw ◽  
Sea Water ◽  
Xylanase Activity ◽  
Agricultural Wastes ◽  
Fungal Isolate ◽  
Main Body ◽  
Xylanase Production

Abstract Background Xylanase enzyme plays an important role in nature as being a part of protecting the environment from pollution. It has also various industrial applications. Main body of abstract Marine fungal isolate was recovered from red sea water at Sharm El-Sheikh province, Egypt, and tested for xylanase activity, using different agricultural wastes as a substrate. It was found that rice straw was the best substrate for xylanase production (0.37 U/ml). Thus, it was subjected for identification by 18S rDNA gene. The phylogenetic analysis results indicated that this fungal isolate belonging to Aspergillus species with a similarity of 99% and named as A. oryzae SS_RS-SH (MN894021). The regular two-level factorial design was used to optimize the important medium components, which significantly affected the xylanase production. The model in equation suggested optimal conditions of 2% of rice straw, 8 g/l of yeast extract, 4 g/l of (NH4)2SO4, 2 g/l K2HPO4, and 2.5 g/l MgSO4.7H2O for a maximum xylanase yield. The antifungal activity of crude xylanase on mycelial growth of some pathogenic fungi isolated from different hosts was investigated. The results showed that xylanase T1 had a potent antifungal activity than control. Greenhouse experiments indicated that all treatments with xylanase at different concentrations significantly decreased infection occurrence of beans, which have been effectively infected with root rot pathogens, compared to unprocessed control treatments. Short conclusion Xylanase yield increased 2.43-folds than initial screening. The xylanase had a potential antifungal activity both in vitro and under greenhouse conditions. The outcome of this study ensured that this fungal strain could be used as biological control for plant disease.

Effect of Overexpression of the HAC1 Genes from Pichia pastoris and Saccharomyces cerevisiae on the Heterologous Phytase and Xylanase Production by P. pastoris

2019 ◽  
Vol 35 (6) ◽  
pp. 57-66
Author(s):  
L.N. Borshchevskaya ◽  
A.N. Kalinina ◽  
S.P. Sineoky ◽  
M.D. Kashirskaya
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Pichia Pastoris ◽  
Xylanase Activity ◽  
Ministry Of Education ◽  
Transcription Activator ◽  
Xylanase Production ◽  
Codon Composition ◽  
The Russian Federation ◽  
Encoding Genes

Effect of overexpression of the HAC1 genes from Pichia pastoris and Saccharomyces cerevisiae on the production of heterologous enzymes, Escherichia coli phytase and Paenibacillus brasilensis xylanase, in P. pastoris cells has been studied. Codon composition of the phytase and xylanase encoding genes was optimized, and the genes were expressed in P. pastoris under the control of AOX1 promoter. The obtained multi-copy strains produced in vitro 927 U/mL phytase and 1,401 U/ml xylanase activity. Overexpression of the HAC1 gene from P. pastoris was shown to increase the phytase and xylanase production by 46% and 41%, respectively. Overexpression of HAC1 from S. cerevisiae increased the phytase production by 28% and xylanase by 20%. Data obtained could be helpful in the construction of industrial enzyme-producing strains based on P. pastoris. phytase, xylanase, Нас1р transcription activator, UPR, Pichia pastoris, Saccharomyces cerevisiae The work was carried out using Multipurpose Scientific Installation All-Russian Collection of Industrial Microorganisms National Bioresource Center, NRC «Kurchatov Institute» -GosNIIgenetika. The authors are grateful to A.V. Nikulin (Sintol LLC, Russia) for the assistance in the real-time PCR experiments. The work was financially supported by the Ministry of Education and Science of the Russian Federation (Unique Identifiers of the Projects are RFMEFI57917X0145 and RFMEFI60717X0180).

Cellulase and xylanase activity of the rumen anaerobic fungi grown on untreated and sodium hydroxide treated barley straw

1999 ◽  
Vol 1999 ◽  
pp. 152-152
Author(s):  
M. Rezaeian ◽  
D. S. Parker ◽  
G. W. Beakes
Keyword(s):  
Sodium Hydroxide ◽  
Dry Matter ◽  
Nutritive Value ◽  
Culture Media ◽  
Xylanase Activity ◽  
Barley Straw ◽  
Anaerobic Fungi ◽  
Dry Matter Loss ◽  
The World

The treatment of straw with sodium hydroxide in order to upgrade its nutritive value and to increase the utilisation of its energy by ruminants has been widely employed in many parts of the world. The aim of the experiment was to assess the fibrolytic activity of the anaerobic fungi in vitro using either untreated or NaOH treated barley straw.Anaerobic fungi were isolated from the rumen of a sheep fed with a diet of hay and lucerne pellets using medium C based on that described by Davies et al. (1993) and as modified by Rezaeian (1996). The Isolates were inoculated into two series of culture media containing either sodium hydroxide treated (TS) or untreated milled straw (US). Five replicate cultures were prepared and incubated at 39 °C over a period of 12 days. The dry matter loss of the substrates and changes in pH of the medium cultures were measured.

scholarly journals Characterisation and effects of a xylanase enzyme preparation extracted from Thermomyces lanuginosus cultures

2001 ◽  
Vol 49 (2) ◽  
pp. 175-184 ◽  
Author(s):  
J. Kutasi ◽  
Á. Bata ◽  
E. Brydl ◽  
P. Rafai ◽  
V. Jurkovich
Keyword(s):  
Thermal Resistance ◽  
Wheat Bran ◽  
Dry Matter ◽  
Enzyme Preparation ◽  
Xylanase Activity ◽  
Thermomyces Lanuginosus ◽  
Xylanase Enzyme ◽  
Oat Straw ◽  
Lignocellulolytic Activity

This paper describes the production of an enzyme preparation from the fungus Thermomyces lanuginosus. Thermal resistance, pH stability and lignocellulolytic activity of the enzyme preparation high in xylanase were studied on a variety of grains and forages. The enzyme preparation preserved more than 70% of its original xylanase activity for 4 and 1 h at 60 and 70 °C, respectively. The xylanase activity remained over 80% when the preparation was incubated for 30 min at pH 4.5. In vitro digestibility studies indicated that the enzyme digested 7.5, 8.5 and 8.0% of the dry matter (DM) of barley meal, wheat bran and oat meal samples, respectively. When applying 60-min incubation, 7.5, 7.3 and 8.4% of DM of the oat straw, alfalfa hay and triticale straw was digested, respectively. When the time of digestion was increased to 360 min, the sunflower hull showed 15.8% DM digestibility.

Correlative Analysis of Cochliobolus sativus Pathogenicity and in vitro Xylanase Activity

2009 ◽  
Vol 158 (6) ◽  
pp. 444-447 ◽  
Author(s):  
Yasser Bakri ◽  
Mohammed Jawhar ◽  
Mohammed Imad Eddin Arabi
Keyword(s):  
Xylanase Activity ◽  
Cochliobolus Sativus ◽  
Correlative Analysis

Efficacy of exogenous xylanases for improving in vitro fermentation of forages

2014 ◽  
Vol 153 (3) ◽  
pp. 538-553 ◽  
Author(s):  
Z. X. HE ◽  
L. Y. YANG ◽  
W. Z. YANG ◽  
K. A. BEAUCHEMIN ◽  
S. X. TANG ◽  
...  
Keyword(s):  
Volatile Fatty Acids ◽  
Xylanase Activity ◽  
Ammonia Nitrogen ◽  
Positive Control ◽  
Linear Increase ◽  
Gas Production ◽  
Pennisetum Purpureum ◽  
Ruminal Fermentation ◽  
Positive Effects

SUMMARYBatch cultures of mixed rumen micro-organisms were used to evaluate varying enzyme products with high xylanase activity (EPX), four of which were recombinant single xylanase activity developmental enzyme products (EPX1–EPX4, products of xylanase genes derived from Trichoderma harzianum, Trichoderma reesei, Orpinomyces and Aspergillus oryzae, respectively), for their potential to improve in vitro ruminal fermentation of three forages [maize (Zea mays) stover (MS), rice (Oryza sativa) straw (RS) and Guimu No. 1 grass (Pennisetum americanum×Pennisetum purpureum, GM)]. The enzyme product EPX5, derived from Trichoderma longibrachiatum, was used as a positive control that could improve in vitro fermentation of forages. Enzymes were supplied at dose rates of 0 (control), 20 (low), 50 (medium) and 80 (high) enzymic units of xylanase/g of dry matter (DM). There were no interactions between EPX and dose for the fermentation characteristics evaluated. Increasing EPX dose linearly increased gas production (GP) kinetic characters [i.e. asymptotic GP (VF), half time when GP is half of the theoretical maximum GP (t0·5), and initial fractional rate of degradation (FRD0)] and methane (CH4) production from RS and GM at 24 h, and increased degradability of DM at 24 h for MS and RS. A linear increase in degradability of neutral detergent fibre (NDF) of the three forages at 24 h was observed with increasing dose of EPX, but at 48 h only NDF degradability of RS was increased. There were differences in the effects of EPX on degradability of DM and NDF from RS at 24 h, with EPX4 having the highest and EPX1 having the lowest. In addition, increasing EPX dose linearly increased acetate proportion at 24 h and total volatile fatty acids (TVFA) at 48 h in MS. Increasing EPX dose linearly increased TVFA at 24 h, and ammonia-nitrogen (NH3-N) concentration at 48 h in RS. For GM, linear or quadratic effects of dose on acetate and butyrate concentration were observed at 24 and 48 h. The present study indicates that applying EPX to low-quality forages has the potential to improve rumen degradability and utilization. Furthermore, EPX from different sources differed in their effects when applied at the same dose rate, with the responses being forage-specific. For RS, the EPX derived from A. oryzae showed the greatest positive effects on forage degradation; whereas for MS and GM, the source of micro-organism where EPX gene was derived did not affect the degradation, with little difference among the EPX evaluated.

Assessment of the potential of feed enzyme additives to enhance utilization of corn silage fibre by ruminants

2008 ◽  
Vol 88 (1) ◽  
pp. 97-106 ◽  
Author(s):  
Jong-Su Eun ◽  
Karen A Beauchemin
Keyword(s):  
Dry Matter ◽  
Xylanase Activity ◽  
Enzymic Activity ◽  
Gas Production ◽  
Corn Silage ◽  
Endoglucanase Activity ◽  
Rumen Microorganisms ◽  
Vitro Assay ◽  
Acid Detergent Fibre

We hypothesized that the fermentation of corn silage by a mixed culture of rumen microorganisms in an in vitro system could be increased using exogenous fibrolytic enzyme additives (FE), and that the improvement would depend on the dose of cellulase or xylanase activity provided. An in vitro assay was used to determine the effects of FE on gas production (GP) and degradability of fibre after 24 h of incubation in buffered ruminal fluid. Eight FE with endoglucanase and xylanase activities were evaluated at one dose (0.5 mg g-1 of forage dry matter), providing variable units of enzymic activity. Only one product improved fibre degradability (9.1 and 29.9% increases for neutral and acid detergent fibre, respectively; P < 0.05). The FE were reassessed when added to supply the same dose of enzymic activity: 807 units of endoglucanase or 477 units of xylanase activity g-1 of forage dry matter (a unit was defined as nmol of reducing sugar released min-1). The FE had greater impact on GP (21% increase; P < 0.05) and fibre degradation (29 and 60% increases for neutral and acid detergent fibre, respectively; P< 0.05) when equalized for endoglucanase activity than when equalized for xylanase activity. Enzyme products high in endoglucanase activity and low in xylanase activity have the potential to improve the use of corn silage by ruminants. Key words: Corn silage, degradability, exogenous fibrolytic enzymes, gas production

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