Xylanase Production Research Articles

Seasonal stability of the rumen microbiome contributes to the adaptation patterns to extreme environmental conditions in grazing yak and cattle

BackgroundThe rumen microbiome plays an essential role in maintaining ruminants’ growth and performance even under extreme environmental conditions, however, which factors influence rumen microbiome stability when ruminants are reared in such habitats throughout the year is unclear. Hence, the rumen microbiome of yak (less domesticated) and cattle (domesticated) reared on the Qinghai-Tibetan Plateau through the year were assessed to evaluate temporal changes in their composition, function, and stability.ResultsRumen fermentation characteristics and pH significantly shifted across seasons in both cattle and yak, but the patterns differed between the two ruminant species. Ruminal enzyme activity varied with season, and production of xylanase and cellulase was greater in yak compared to cattle in both fall and winter. The rumen bacterial community varied with season in both yak and cattle, with higher alpha diversity and similarity (beta diversity) in yak than cattle. The diversity indices of eukaryotic community did not change with season in both ruminant species, but higher similarity was observed in yak. In addition, the similarity of rumen microbiome functional community was higher in yak than cattle across seasons. Moreover, yak rumen microbiome encoded more genes (GH2 and GH3) related to cellulose and hemicellulose degradation compared to cattle, and a new enzyme family (GH160) gene involved in oligosaccharides was uniquely detected in yak rumen. The season affected microbiome attenuation and buffering values (stability), with higher buffering value in yak rumen microbiome than cattle. Positive correlations between antimicrobial resistance gene (dfrF) and CAZyme family (GH113) and microbiome stability were identified in yak, but such relationship was negatively correlated in cattle.ConclusionsThe findings of the potential of cellulose degradation, the relationship between rumen microbial stability and the abundance of functional genes varied differently across seasons and between yak and cattle provide insight into the mechanisms that may underpin their divergent adaptation patterns to the harsh climate of the Qinghai-Tibetan Plateau. These results lay a solid foundation for developing strategies to maintain and improve rumen microbiome stability and dig out the potential candidates for manufacturing lignocellulolytic enzymes in the yak rumen to enhance ruminants’ performance under extreme environmental conditions.

Genetic Diversity and Functional Potential of Streptomyces spp. Isolated from Pachmarhi Biosphere Reserve, India.

Streptomyces is a diverse genus, well known for producing a wide array of metabolites that have significant industrial utilization. The present study investigates the genetic and functional diversity of Streptomyces spp. isolated from the Pachmarhi Biosphere Reserve (PBR), India, an unexplored site. The 16S rRNA gene sequencing and analysis revealed 96 isolates belonging to 40 different species indicating a substantial phylogenetic diversity. The strains were clustered into two groups: a major cluster with 94 strains and a small cluster with two strains. BOX- PCR analyses revealed an incredible genetic diversity existing among the strains of Streptomyces spp. in PBR. The analyses revealed the intra-species diversity and inter-species closeness within the genus Streptomyces in the study area. Qualitative screening for enzyme production has shown that 53, 42, 41, 11, and 54 strains tested positive for CMCase, xylanase, amylase, pectinase, and β-glucosidase, respectively. Additionally, 54 strains tested positive for PHB production. The strains were assayed quantitatively for the production of CMCase, xylanase, amylase, and pectinase. Streptomyces sp. MP9-2, Streptomyces sp. MP10-11, Streptomyces sp. MP10-18, and Streptomyces sp. MP10-6 recorded maximum CMCase (0.604 U/mL), xylanase (0.553 U/mL), amylase (1.714 U/mL), and pectinase (13.15 U/mL) activities, respectively. Furthermore, several strains demonstrated plant growth-promoting traits, viz. zinc and phosphate solubilization and production of ammonia, HCN (hydrogen cyanide), and IAA (Indole acetic acid), and nitrogen fixation. Fifty strains showed antifungal activity against Fusarium oxysporum f. sp. lycopersici with inhibitions ranging from 7.5 to 47.5%. Current findings underscore the ecological and biotechnological significance of Streptomyces spp. in the unexplored habitat of PBR.

Production and Optimization of Xylanase Enzyme from Bacillus cereus by Submerged Fermentation Method

Three strains of Bacillus cereus were isolated from soil samples in this study in an effort to enhance the circumstances for the production of xylanase by the bacteria. The bacteria released extracellular xylanase throughout the submerged fermentation process. In a 250 ml conical flask, the whole fermentation process was conducted at 150 rpm stirring speed. The highest amount of xylanase synthesis was demonstrated by the isolated strains at 45°C, 48 hours of incubation, pH 5, 1.5% oat splet xylan base concentration, lactose carbon source, and beef extract source.

Kinetics of cellulase-free endo xylanase hyper-synthesis by Aspergillus Niger using wheat bran as a potential solid substrate

The present study deals with the production of cellulase-free endoxylanase by Aspergillus niger ISL-9 using wheat bran as a solid substrate. Endoxylanase was produced under a solid-state fermentation. Various growth parameters were optimized for the improved production of the enzyme. The Substrate level of 15 g was optimized as it provided the fungus with balanced aeration and nutrition. Among the six moisture contents investigated, Moisture Content 5 (MC5) was optimized (g/l: malt extract, 10; (NH4)2HPO4, 2.5; urea, 1.0) and 10 mL of MC5 was found to give the highest production of endoxylanase. The pH and time of incubation were optimized to 6.2 and 48 h respectively. The Inoculum size of 2 mL (1.4 × 106 spores/mL) gave the maximum enzyme production. After optimization of these growth parameters, a significantly high endoxylanase activity of 21.87 U/g was achieved. Very negligible Carboxymethylcellulase (CMCase) activity was observed indicating the production of cellulase-free endoxylanase. The notable finding is that the endoxylanase activity was increased by 1.4-fold under optimized conditions (p ≤ 0.05). The overall comparison of kinetic parameters for enhanced production of endoxylanase by A. niger ISL-9 under Solid State Fermentation (SSF) was also studied. Different kinetic variables which included specific growth rate, product yield coefficients, volumetric rates and specific rates were observed at 48, 72 and 96 h incubation time and were compared for MC1 and MC5. Among the kinetic parameters, the most significant result was obtained with volumetric rate constant for product formation (Qp) that was found to be optimum (1.89 U/h) at 72 h incubation period and a high value of Qp i.e.1.68 U/h was also observed at 48 h incubation period. Thus, the study demonstrates a cost-effective and environmentally sustainable process for xylanase production and exhibits scope towards successful industrial applications.

Combinational manipulation of transcription factors, CreA and ClbR, is a viable strategy to improve cellulolytic enzyme production in Aspergillus aculeatus

The production of cellulolytic enzymes in response to inducible carbon sources is mainly regulated at the transcriptional level in filamentous fungi. We have identified a cellobiose-response regulator (ClbR) controlling the expression of cellulolytic enzyme-encoding genes in Aspergillus aculeatus. However, the engineering potential of combining the deletion of transcriptional repressors with the overexpression of transcriptional activators to enhance enzyme production has not been analyzed. Here, we investigated the effect of the deletion of the transcriptional repressor creA and the overexpression of the transcriptional activator clbR in enzyme production in A. aculeatus. Here, we verified that a combination of creA deletion and clbR overexpression (Δc&OE) improved cellulase, β-1,4-xylanase, and β-glucosidase production. Cellulase and β-1,4-xylanase production increased 3.4- and 8.0-fold in Δc&OE compared with the host strain (MR12) at 96-h incubation, respectively. β-Glucosidase production in ΔcreA and Δc&OE increased approximately 5.0-fold compared with that in MR12 at 240 h-incubation. Transcriptional analysis revealed that the increase in enzyme production was due to increased expression of cellobiohydrolase, endo-β-1,4-glucanase, β-1,4-xylanase, and β-glucosidase 1 (bgl1). Interestingly, bgl1 expression in ΔcreA increased in a dose-dependent manner in response to glucose. Thus, combinational manipulation of transcription factors improved cellulase, xylanase, and β-glucosidase production in A. aculeatus.

Production and characterization of acidophilic xylanase from wood degrading white rot fungus by solid-state fermentation of wheat straw

Xylanases (EC 3.2.1.8) catalyze the breakdown of xylan, which is the second most abundant polysaccharide in plant cell walls. Biological catalysts have gained greater global attention than chemical catalysts in different industrial processes because they are highly selective, easy to control and have a negligible environmental impact. The aim of this study was to investigate the xylanolytic potential of white-rot fungi, optimize their physicochemical conditions and characterize the resulting xylanase. Sixty-eight white-rot fungus (WRF) isolates were screened for their xylanolytic potential and growth conditions for maximal xylanase production using cheap agricultural residue (wheat straw) as the sole carbon source. Five WRF isolates with high xylanase yields (73.63 ± 0.0283–63.6 ± 0.01247 U/ml) were selected by qualitative and quantitative screening methods. The optimum xylanase production occurred at pH 5.0 and 28 °C. Solid-state fermentation (SSF) yielded a high amount of xylanase. The highest xylanase activity (80.9–61.274 U/mL) was recorded in the pH range of 5.0–6.5 and at 50 °C. The metal ions Mg2+, Ca2+ and Mn2+ enhanced the activity of xylanase (127.28–110.06 %), while Cu2+, Fe2+ and K+ inhibited the activity with 43.4–17 % losses. The km and Vmax were 0.32–0.545 mg/mL and 86.95–113.63 μmol/min/mg, respectively. This finding indicates that wheat straw can be used for large-scale xylanase production under SSF conditions. The pH and temperature profiles and stabilities indicate that the xylanase produced in the present study can be applied in food and animal feed industries.

Optimization and Characterization of an Ultra-Thermostable, Acidophilic, Cellulase-Free Xylanase from a New Obligate Thermophilic Geobacillus thermoleovorans AKNT10 and its Application in Saccharification of Wheat Bran.

Microbial xylanases are enzymes of great importance due to their wide industrial applications, especially in the degradation of lignocellulosic biomass into fermentable sugars. This study aimed to describe the production optimization and partial characterization of an ultra-thermostable, acidophilic, cellulase-free xylanase from an obligate thermophilic eubacterium Geobacillus thermoleovorans strain-AKNT10 (Ac.No. LT158229) isolated from a hot-spring of Puga Valley located at an altitude of 4419m in Ladakh, India. The optimization of cultural conditions improved enzyme yield by 10.49-fold under submerged fermentation. The addition of 1% (w/v) xylose induced the enzyme synthesis by ~ 165 and 371% when supplemented in the fermentation medium containing wheat bran (WB) 1 and 3%, respectively. The supplementation of sucrose reduced the xylanase production by ~ 25%. Results of partial characterization exhibited that xylanase was optimally active at pH 6.0 and 100°C. Enzyme retained > 75%, > 83%, and > 84% of activity at 4°C for 28days, 100°C for 60min, and pHs 3-8 for 60min, respectively. An outstanding property of AKNT10-xylanase, was the retention of > 71% residual activity at extreme conditions (121°C and 15 psi pressure) for 15min. Enzymatic saccharification showed that enzyme was also capable to liberate maximum reducing sugars within 4-8h under optimized conditions thus it could be a potential candidate for the bioconversion of lignocellulosic biomass as well as other industrial purposes. To the best of our knowledge, this is the first report on such an ultra-thermo-pressure-tolerant xylanase optimally active at pH6 and 100°C from the genus Geobacillus.

Isolation and Identification of Xylanase Producing Bacteria from Soil Samples of Kerala

Microorganisms play a very vital role in the biological recycling of plant bio-matter. Xylan is the second most plentiful polysaccharide and is found as an interface between lignin and other polysaccharide in the secondary cell wall. When these polysaccharides are hydrolyzed by a suitable strain of bacteria it will become an end to many environmental issues and had many useful applications such as in paper and pulp industry, food and feed industry, bread quality improvement, agro waste treatment, seed germination, generation of bio-fuels etc. To isolate a suitable strain of bacteria which possess good xylanase activity several samples of soils were collected from various regions of Kerala and were undergone a three step enrichment process. In the primary screening 85 bacterial strains were obtained. 22 isolates produces clear zone during plate assay using beech wood xylan. The isolates which possess more than 0.5cm clear zone were undergone final screening process and the strain PSS 1 showed the maximum enzyme activity of 112.38 U/ml.

Transcriptomic and metabolic changes in Trichoderma reesei caused by mutation in xylanase regulator 1 (xyr1)

BackgroundTrichoderma reesei is known for its ability to produce large amounts of extracellular proteins and is one of the most important industrially used filamentous fungus. Xylanase regulator 1 (XYR1) is the master regulator responsible for the activation of cellulase and hemicellulase gene expression under inducing conditions. It has been reported that strains with point mutations in certain areas of xyr1 bypass the need for inducing carbon source, allowing high (hemi)cellulase production even in the presence of glucose. These mutations also change the profile of produced proteins, shifting it more towards xylanase production, and increase the overall protein production in inducing conditions. However, how these mutations alter the metabolism and other cellular processes to cause these changes remains unclear.ResultsIn this study, we aimed to explore changes caused by a point mutation in xyr1 on transcriptomic and metabolic level to better understand the reasons behind the increased protein production in both repressing glucose and inducing lactose conditions. As expected, the expression of many carbohydrate-active enzyme (CAZy) genes was increased in the xyr1 mutant in both conditions. However, their induction was higher under inducing conditions. The xyr1 mutant strain built more biomass and produced more extracellular proteins during growth on lactose compared to the wild type xyr1 strain. Genes involved in oxidoreductive D-galactose catabolism pathway were upregulated in the xyr1 mutant strain, potentially contributing to the more efficient utilization of lactose. In addition to CAZy genes, clustering and enrichment analysis showed over-representation of mitochondria-related Gene Ontology terms in clusters where gene expression was higher in the xyr1 mutant, indicating that mitochondria play a role in the altered metabolic state associated with the xyr1 mutation. Metabolomics revealed that free tyrosine was more abundant in the xyr1 mutant strain in all measured timepoints, whereas multiple fatty acids were less abundant in the mutant strain on glucose.ConclusionsThe results contribute to more in-depth knowledge on T. reesei physiology growing under inducing and repressing carbon sources and gives new insights on the function of the master regulator XYR1. The vast data generated serve as a source for new targets for improved protein production.

Development of polysaccharide bioplastic: Analysis of thermo-mechanical properties and different environmental implications

Despite the distinct benefits of plastics, the environmental impacts stemming from their production and accumulation in the environment have become a global concern. Therefore, the development of new technologies that mitigate these impacts is of notable importance. The present study aimed to evaluate the physicochemical properties of starch-xylan-based bioplastic, and to discuss the viability of this material in terms of applications and ecological impacts. Holocellulose, xylan, and α-cellulose were extracted from waste biomass and combined with starch for bioplastic production. Solubility in food simulants (3% acetic acid, and 90% ethanol) was performed for xylan and starch-based bioplastics. Bioplastic was evaluated to grow Aspergillus versicollor for xylanase production. The bioplastic was evaluated as a photoprotector with yeast exposed to UVC light-covered by the bioplastic for 2 h. Bioplastic disintegration was evaluated in different soil moistures and the disintegration on the surface of the compost. Liquid washes from soils exposed to bioplastic biodegradation were tested for Lactuca sativa seed germination/inhibition. Water from a local lake was exposed to bioplastic and microbial cell density modification was verified. Images of the surface of the bioplastics were obtained by scanning electron microscopy, and characterized by thermogravimetric and dynamic-mechanical analysis. The xylan addition in bioplastic led to a material with a 40–50% decreased ultraviolet light transmittance. An increase in xylan concentration reduced solubility in lipid food simulant solutions, with no fatty solubilization with 25% of xylan. It suggests potential applications in photoprotective and packaging contexts. The thermal degradation temperature of the pure starch bioplastic was 324 °C, and the addition of 10% (287 °C), 15% (286 °C), and 25% (296 °C) xylan (w/w) indicated a reduction in thermal resistance, possibly due to suboptimal interaction between polymer chains. The decrease in crystallinity in the compositions 10/90% (Xc = 20%), 15/85% xylan/starch (Xc = 21%) compared to 25/75% xylan/starch (Xc = 11%) also underscored the complexity of polymer interactions within the bioplastic matrix. Tensile strength of pure starch was 1.21 MPa, while the composition of 15/85% xylan/starch exhibited improved strength 2.99 MPa. Further investigation into the interaction between starch and xylan is warranted. Concerning the disintegration of the 25/75% xylan/starch formulation in the soil, the humidity of the soil matrix played a significant role. The disintegration occurred over 5 days and 16 days in compost (55% humidity) and soil (32.6% humidity), respectively. The results of phytotoxicity (Lactuca sativa seeds) and changes in the physicochemical and biological profile of water (smell, turbidity, phosphorus and nitrogen levels, pH, and bacterial and phytoplankton density/richness), in response to exposure to bioplastics, highlight the necessity of developing this biologically-based and biodegradable technology in concerns about potential environmental impacts. Furthermore, the present study introduces the approach of bioplastic waste recycling using enzyme production biotechnology. In line with the legitimacy of bioplastics as important materials for addressing the challenges posed by their non-biodegradable synthetic counterparts, the presented results broaden the discourse on the feasibility of this biologically based material, contributing to the development of a sustainable society.

Cryptococcus laurentii: a wild yeast for xylanase production from agricultural by-products.

The development of technologies that allow the production of enzymes at a competitive cost is of great importance for several biotechnological applications, and the use of agro-industrial by-products is an excellent alternative to minimize costs and reduce environmental impacts. This study aimed to produce endo-xylanases using agro-industrial substrates rich in hemicellulose as sources of xylan in culture media. For this purpose, the yeast Cryptococcus laurentti and five lignocellulosic materials (defatted rice bran, rice husk, corn cob, oat husks, and soybean tegument), with and without pretreatment, were used as a source of xylan for enzyme production. To insert the by-products in the culture medium, they were dried and treated (if applicable) with 4% (w.v-1) NaOH and then added in a concentration of 2% (w.v-1). The cultures were agitated for 96h, and the aliquots were removed to determine the enzymatic activities. Among the by-products studied, the maximum activity (8.7 U. mL-1 at pH 7.3) was obtained where rice bran was used. In contrast, corn cob was the by-product that resulted in lower enzyme production (1.6 U.mL-1). Thus, the defatted rice bran deserves special attention in front of the other by-products used since it provides the necessary substrate for producing endo-xylanases by yeast.

Isolation, Screening and Characterization of Xylose-Fermenting Yeasts Isolated from Saw Dust

Yeasts have been less frequently reported as xylanase producers compared to bacteria and filamentous fungi. Different cellulosic materials including sawdust are produced on a large scale and these can be used for the production of useful enzymes such as xylanases. Xylanases are a group of enzymes that hydrolyze plant fibers made of xylan hemicellulose. Xylose-fermenting yeasts isolated from soil at a wood processing factory were isolated and qualitatively and quantitatively screened for xylanase production using xylose supplemented medium and congo red as indicator. Xylanase enzyme was produced using different xylose concentrations (0.5%, 1.0%, 1.5% and 2.0%). Pichia chambardii isolate, which was later identified as Wickerhamomyces chambardii by molecular techniques, showed the highest xylanase activity of 199.31U mL-1. Maximum xylanase activity (275.83U mL-1) was achieved at 1.5 %w/v xylose. This study showed that yeasts have a high potential for the production of xylanase enzymes.

Production of xylanase intended to be used in bread-making: laboratory scale and pilot scale studies

In this study, submerged and solid-state fermentation studies were performed for xylanase production simultaneously to determine ideal carbon and nitrogen sources together with necessary production parameters from the laboratory scale to the pilot scale. The results showed that barley malt sprout is effective as a nitrogen and a good carbon source. Under optimum conditions, xylanase activities 71.74 ± 2.70 U/mL, 56.95 ± 3.6 U/mL, 65.8 ± 8 U/mL and 46.05 ± 0.1 U/mL were achieved in shake flasks, 2, 10 and 30 L bioreactors, respectively. In solid-state fermentation studies, maximum activity in flasks was 759.15 ± 36.16 U/g production media, and maximum activity in pilot-scale tray bioreactor productions was 1312 ± 137.85 U/g dry substrate. Bread-making trials showed that using xylanase at 100 U/100g flour resulted in a significant increase in the loaf volume of wheat flour bread and whole wheat flour bread.

Unlocking the potential of Algerian lignocellulosic biomass: exploring indigenous microbial diversity for enhanced enzyme and sugar production.

Nowadays, natural resources like lignocellulosic biomass are gaining more and more attention. This study was conducted to analyse chemical composition of dried and ground samples (500μm) of various Algerian bioresources including alfa stems (AS), dry palms (DP), olive pomace (OP), pinecones (PC), and tomato waste (TW). AS exhibited the lowest lignin content (3.60 ± 0.60%), but the highest cellulose (58.30 ± 2.06%), and hemicellulose (20.00 ± 3.07%) levels. DP, OP, and PC had around 30% cellulose, and 10% hemicellulose. OP had the highest lignin content (29.00 ± 6.40%), while TW contained (15.70 ± 2.67% cellulose, 13.70 ± 0.002% hemicellulose, and 17.90 ± 4.00% lignin). Among 91 isolated microorganisms, nine were selected for cellulase, xylanase, and/or laccase production. The ability of Bacillus mojavensis to produce laccase and cellulase, as well as B. safensis to produce cellulase and xylanase, is being reported for the first time. In submerged conditions, TW was the most suitable substrate for enzyme production. In this conditions, T. versicolor K1 was the only strain able to produce laccase (4,170 ± 556 U/L). Additionally, Coniocheata hoffmannii P4 exhibited the highest cellulase activity (907.62 ± 26.22 U/L), and B. mojavensis Y3 the highest xylanase activity (612.73 ± 12.73 U/L). T. versicolor K1 culture showed reducing sugars accumulation of 18.87% compared to initial concentrations. Sucrose was the predominant sugar detected by HPLC analysis (13.44 ± 0.02g/L). Our findings suggest that T. versicolor K1 holds promise for laccase production, while TW represents a suitable substrate for sucrose production.

Heterologous expression and structure prediction of a xylanase identified from a compost metagenomic library

Xylanases are key biocatalysts in the degradation of the β‐1,4‐glycosidic linkages in the xylan backbone of hemicellulose. These enzymes are potentially applied in a wide range of bioprocessing industries under harsh conditions. Metagenomics has emerged as powerful tools for the bioprospection and discovery of interesting bioactive molecules from extreme ecosystems with unique features, such as high temperatures. In this study, an innovative combination of function-driven screening of a compost metagenomic library and automatic extraction of halo areas with in-house MATLAB functions resulted in the identification of a promising clone with xylanase activity (LP4). The LP4 clone proved to be an effective xylanase producer under submerged fermentation conditions. Sequence and phylogenetic analyses revealed that the xylanase, Xyl4, corresponded to an endo-1,4-β-xylanase belonging to glycosyl hydrolase family 10 (GH10). When xyl4 was expressed in Escherichia coli BL21(DE3), the enzyme activity increased about 2-fold compared to the LP4 clone. To get insight on the interaction of the enzyme with the substrate and establish possible strategies to improve its activity, the structure of Xyl4 was predicted, refined, and docked with xylohexaose. Our data unveiled, for the first time, the relevance of the amino acids Glu133 and Glu238 for catalysis, and a close inspection of the catalytic site suggested that the replacement of Phe316 by a bulkier Trp may improve Xyl4 activity. Our current findings contribute to enhancing the catalytic performance of Xyl4 towards industrial applications.Key points• A GH10 endo-1,4-β-xylanase (Xyl4) was isolated from a compost metagenomic library• MATLAB’s in-house functions were developed to identify the xylanase-producing clones• Computational analysis showed that Glu133 and Glu238 are crucial residues for catalysisGraphical abstract

235 Evaluation of an exogenous fibrolytic enzyme combination in forage-based growing diets fed to growing beef cattle

Abstract Crossbred steers [n = 73; 287±19 kg initial body weight (BW)] were used in an 84-d growing study to investigate the effects of feeding an exogenous xylanase and cellulase combination product (EFE) and wheat straw (WS) inclusion level on the growth performance of growing beef cattle. Treatments were arranged as a 2 × 2 factorial with two levels of WS, either 5% (low; LS) or 15% (high; HS) of diet dry matter, and two inclusion rates of exogenous fibrolytic enzymes, 0 (none; N) or 750 g/ton (enzyme; E; Bovizyme CX; Danisco Animal Nutrition and Health; Wilmington, DE) of diet. Body weights and blood samples were collected every 28 d. Individual intake data were collected using an automated feeding system (Insentec Roughage Intake Control, Hokofarm B.V., Marknesse, The Netherland). Average daily gain (ADG), dry matter intake (DMI), gain to feed ratio (G:F), plasma glucose (GLU), plasma non-esterified fatty acids (NEFA), and plasma urea nitrogen (PUN) were analyzed using PROC MIXED (SAS Ins. Inc., Cary, N.C.). Animal was the experimental unit and fixed effects included blocks of body weight (n = 3) and original source of steers (n = 2). The model included the level of WS (LS, HS), level of EFE (N or E), and WS × EFE interactions. There were no WS × EFE interactions (P ≥ 0.31) for all measured traits. Supplementing EFE resulted in no differences (P ≥ 0.16) for ending BW, ADG, DMI, G:F, NEFA, and PUN. However, within HS diet, inclusion of E numerically increased ADG by 0.05 kg/d compared with N (1.29 vs. 1.24 kg/d; HSE vs. HSN, respectively; P > 0.31). Steers consuming E diets tended to have greater GLU compared with N (4.92 vs. 4.80 µmol/L, respectively; P = 0.10). Between levels of straw inclusion, ending BW was greater for steers consuming LS diet compared with HS diet (413 vs. 393 kg, respectively; P < 0.0001). Resulting in greater ADG for steers consuming LS diet compared with HS diet (1.49 vs. 1.26 kg, respectively; P < 0.01). Dry matter intake was greater for steers consuming LS diet than HS diet (9.06 vs. 8.33 kg, respectively; P < 0.01). Therefore, G:F was improved for steers consuming LS diet compared with HS diet (0.165 vs. 0.151, respectively; P < 0.01). Steers consuming LS diet had decreased NEFA compared with HS diet (311 vs. 376 µmol/L, respectively; P < 0.01). Results from this study indicate that regardless of the inclusion level of WS, supplementing growing steers with EFE did not influence growth performance. However, replacing ten percent of corn silage with WS reduced the energy concentration of the diet, decreasing growth performance.

Effectiveness mutagenesis of Bacillus subtilis using EMS (Ethyl Methane Sulfonate) to increase xylanase enzyme activity

This research was conducted to determine the effect of mutagenizing Bacillus subtilis with Ethyl Methane Sulfonate (EMS) for xylanase production and evaluate the effect of different xylan concentrations from corn cobs. The xylanase enzyme is an enzyme that can reduce the xylan content which is an anti-nutrient in animal feed. The wild-type Bacillus subtilis was treated with 50 μg/ml and 100 μg/ml of EMS. The mutants generated were selected for xylanase production in a medium containing xylan from corn cobs as a carbon source. The parameters observed included: Total Plate Count (TPC) and reducing sugar (xylose). Protein concentration and xylanase enzymes were analyzed using the Bradford method and 3.5 Dinitro salicylic acid for reducing sugar according to Miller methods respectively. Five mutants developed from each of the EMS concentrations. Approximately 6 and 6.8 % of the mutants developed from 50 μg/ml and 100 μg/ml of EMS had higher xylanase activities than the wild type and protein and xylose concentrations were higher than the wild type. From the results of the research, it can be seen that the use of EMS compounds has the potential to increase enzyme activity so that it can be potential in reducing antinutrients in animal feedstuff.

Enhancing Xylanase Production from Aspergillus tamarii Kita and Its Application in the Bioconversion of Agro-Industrial Residues into Fermentable Sugars Using Factorial Design

The endo-1,4-β-xylanases (EC 3.2.1.8) are the largest group of hydrolytic enzymes that degrade xylan, the major component of hemicelluloses, by catalyzing the hydrolysis of glycosidic bonds β-1,4 in this polymer, releasing xylooligosaccharides of different sizes. Xylanases have considerable potential in producing bread, animal feed, food, beverages, xylitol, and bioethanol. The fungus Aspergillus tamarii Kita produced xylanases in Adams’ media supplemented with barley bagasse (brewer’s spent grains), a by-product from brewery industries. The culture extract exhibited two xylanase activities in the zymogram, identified by mass spectrometry as glycosyl hydrolase (GH) families 10 and 11 (GH 10 and GH 11). The central composite design (CCD) showed excellent predictive capacity for xylanase production (23.083 U mL−1). Additionally, other enzyme activities took place during the submerged fermentation. Moreover, enzymatic saccharification based on a mixture design (MD) of three different lignocellulosic residues was helpful in the production of fermentable sugars by the A. tamarii Kita crude extract.

Utilization of Xylanase Enzymes Derived from Cassava in the Eco-Friendly Biobleaching of Pulp

<p align="center">The demand for paper has been increasing over time, leading to the pulp and paper industry becoming one of the largest contributors to global carbon emissions due to the chlorine-based bleaching process, particularly in Indonesia. An alternative to minimize chlorine usage involves using xylanase enzymes as part of the bleaching sequence. Xylanase can be produced from agricultural waste, including cassava residue, which contains a significant concentration of xylanase, approximately 21.3%. However, it still needs to be utilized in Indonesia. Therefore, this study aims to explore the production of xylanase enzymes from cassava residue and assess its effectiveness in the biobleaching process of pulp. The research methodology includes the production phase of xylanase enzymes by <em>Aspergillus niger</em>, chelating, bleaching sequence, bleaching, kappa number, and chemical saving assay. In the production of xylanase, the study determined that xylanase exhibits optimal activity under specific conditions, notably at a pH of 6 and a temperature of 60°C. Under these parameters, the enzymatic activity reached a level of 0.4986 U/mg protein. During the bleaching sequence, xylanase was used with doses of 0.3, 0.5, 0.7, 0.8, and 1 L/T pulp at 40, 45, 50, 55, 60, 65, and 70°C for 60 minutes. Following this process, bleaching was conducted at 65°C for 70 minutes, extraction at 80°C for 90 minutes, and a second bleaching phase. Subsequently, a kappa number test was performed, revealing the best kappa value at 60°C with a xylanase dose of 0.5 L/T pulp, reducing from an initial kappa number of 9 to 4.04. Additionally, under these conditions and dosage, xylanase enzymes could save approximately 23.67% in chlorine usage</p>

Xylanase production by Penicillium sp. Pn004 and its application for grass hydrolysis: high value subproduct from non-centrifugal sugarcane bagasse and wheat bran

Worldwide more than 7 billion tons of lignocellulosic biomass will be produced by 2025. In Colombia, these residues are mainly disposed of in rivers and open fields, and only 10% is reused and recycled. Non-centrifugal sugarcane bagasse (SCB) is a residue obtained after sugarcane juice extraction during the manufacturing process of panela and is mostly used as fuel for boilers at sugar mills. Wheat bran (WB) is the main waste from wheat flour production. Nonetheless, the chemical composition of these by-products makes them suitable for use as substrates for hemicellulolytic enzyme production from fungi. Here, a whole process for production in a solid-state fermentation system, recovery, and ultrafiltration process for concentration of xylanases by Penicillium sp. Pn004 is presented. The higher productivity (26.7 ± 1.59 U gds-1 day-1) was reached on the fifth day of fermentation with an enzyme activity of 130.0 ± 7.95 U gds-1. The batch ultrafiltration process allowed increasing the xylanase activity up to 19-fold in the retentate, from 66.47 U mL-1 to 1486.83 U mL-1, without reaching a steady state flux through the membrane. Finally, the enzymatic extract achieved a 43% release of sugar from kikuyu grass (Cenchrus clandestinus), showing its potential to be used as an additive for silage or for enzymatic saccharification of lignocellulosic materials for sugar production.