Enzyme Activity Of Xylanase Research Articles

Screening, Production and Characterization of Potential Lignocellulolytic Actinomycetes from Agricultural Field

Actinomycetes are a suitable microbial group for the synthesis of lignocellulose-degrading enzymes. Enzymes that may degrade organic material, including cellulose, hemicellulose, and lignin, are released by actinomycetes. The aim of this research was to isolate actinomycetes from Rajkot, Gujarat, India’s soil and evaluate the activity of their cellulase and Xylanase enzymes. Starch Casein Agar (SCA) was used to identify a total of 30 isolates of actinomycetes. A qualitative plate assay (CMC-Na, Congo red) revealed that the highest zone of catalysis for MMD1 was 36 mm. Five strains were discovered to be effective for quantitative quantification of endoglucanase utilising filter paper and CMC as substrates: MMD1, MMD2, MMD3, MMD4, and MMD8. Following MMD 1 (endoglucanase 5.4 IU; FPase 4.4 IU), MMD 2 (endoglucanase 4.5 IU; FPase 3.4 IU) has demonstrated considerable endoglucanase and FPase activity. Beechwood xylan was used to treat sugarcane bagasse in order to test Xylanase, and 45% of the xylan (hemicellulose) fraction was obtained. MMD1 and MMD2 measured the xylanase enzyme activity (4.8IU and 4.2IU) in quantitative and qualitative assays (34 mm and 22 mm for BWX and 32 mm and 14 mm for agro-waste xylan). The strain MMD1 was identified as Streptomyces chartreusis through morphological, biochemical, and finally molecular characterization by 16S rRNA sequencing. It was then submitted to NCBI GenBank with the accession number MT254830.

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.

Produksi Enzim Spesifik Xilanase pada Variasi Suhu Konsorsium Trikultur Bakteri Termofilik

Xylanase is an extracellular enzyme that is capable of hydrolyzing xylan (hemicellulose) into xylose and xylo-oligosaccharides. Xylanase can be produced by microbes through a fermentation process, the microbes used are thermophilic bacteria. Thermophilic bacteria are microorganisms that are capable of producing thermostable enzymes through fermentation. The bacteria used are MSS11, MS 16 and MS 18. These thermophilic bacteria can live at temperatures above 45°C-80°C. To determine specific enzyme activity, enzyme and protein activity values were tested using a 540 nm (enzyme) and 750 nm (protein) septovotometer. The method used in this research is descriptive in triplicate. The research was carried out at the Microbiology Laboratory, Faculty of Mathematics and Natural Sciences, Padang State University on December 23 2023. Beechwood medium which had been mixed with MSS 11, MS 16, and MS 18 bacteria was then incubated at temperatures of 55℃, 65℃ and 75℃ so that specific enzyme activity was obtained. Of these three temperatures, the optimum specific enzyme activity of xylanase is 65℃, where the specific enzyme value obtained at 65℃ is 3.31 U/mg. Meanwhile, at low temperatures, namely at 55℃, the enzymatic reaction is slow, namely it has an enzyme activity value of 1.02 U/mg. Finally, at a temperature of 75, there was a decrease in specific enzyme activity, where the specific enzyme activity value was 3.12 U/mg.

Optimization of xylanase production by Pichia kudriavzevii and Candida tropicalis isolated from the wood product workshop.

Enzymatic compounds can be found abundantly and provide numerous advantages in microbial organisms. Xylanases are used in various pharmaceutical, food, livestock, poultry, and paper industries. This study aimed to investigate xylanase-producing yeasts, xylose concentration curve and their enzymatic activity under various factors including carbon and nitrogen sources, temperature, and pH. Enzyme activity was evaluated under different conditions before, during, and after purification. The yeast strains were obtained from the wood product workshop and were subsequently cultivated on YPD (yeast extract peptone dextrose) medium. Additionally, the growth curve of the yeast and its molecular identification were conducted. The optimization and design process of xylan isolated from corn wood involved the use of Taguchi software to test different parameters like carbon and nitrogen sources, temperature, and pH, with the goal of determining the most optimal conditions for enzyme production. In addition, the Taguchi method was utilized to conduct a multifactorial optimization of xylanase enzyme activity. The isolated species were partially purified using ammonium sulfate precipitation and dialysis bag techniques. The results indicated that 3 species (8S, 18S, and 16W) after molecular identification based on 18S rRNA gene sequencing were identified as Candida tropicalis SBN-IAUF-1, Candida tropicalis SBN-IAUF-3, and Pichia kudriavzevii SBN-IAUF-2, respectively. The optimal parameters for wheat carbon source and peptone nitrogen source were found at 50°C and pH 9.0 through single-factor optimization. By using the Taguchi approach, the best combination for highest activity was rice-derived carbon source and peptone nitrogen source at 50°C and pH 6.0. The best conditions for xylanase enzyme production in single-factor optimization of wheat bran were 2135.6 U/mL, peptone 4475.25 U/mL, temperature 50°C 1868 U/mL, and pH 9.0 2002.4 U/mL. Among the tested yeast, Candida tropicalis strain SBN-IAUF-1 to the access number MZ816946.1 in NCBI was found to be the best xylanase product. The highest ratio of enzyme production at the end of the delayed phase and the beginning of the logarithmic phase was concluded by comparing the growth ratio of 8S, 16W, and 18S yeasts with the level of enzymatic activity. This is the first report on the production of xylan polymer with a relative purity of 80% in Iran. The extracellular xylanases purified from the yeast species of C. tropicalis were introduced as a desirable biocatalyst due to their high enzymatic activity for the degradation of xylan polymers.

Determination of In-vitro Optimum Conditions of Xylanase Enzyme Activity Produced by Orpinomyces sp. and Neocallimastix sp.

This study was aimed to determine the in-vitro optimum conditions of xylanase enzyme activity produced by Orpinomyces sp. and Neocallimastix sp. In the study, xylanase enzyme activity was investigated in terms of extracellular and intracellular total activity (TA) and specific activity (SA) levels at different time (day), pH and temperature levels. Orpinomyces sp. and Neocallimastix sp. when different days (time) were considered in terms of xylanase enzyme activity of fungi species, it was determined that there was a statistically significant positive correlation between TA=0.732 and SA=0.546 (p<0.01). It was determined that there was a statistically positive and significant relationship between TA=0.622 and SA= 0.520 at different pH levels. This situation differs in terms of temperature levels. It was determined that there was a statistically negative significant relationship between genders and SA=-0.354 (p<0.05). In this study, it is thought to contribute by determining the optimum conditions in in-vitro and industrial uses.

TEMPERATURE AND PH OPTIMIZATION OF CAR THERMOPHILIC BACTERIA FOR THE PRODUCTION OF XILANASE THE BLEACHING OF ENVIRONMENTALLY FRIENDLY INKED PAPER WASTE

Xylanase is an extracellular enzyme capable of hydrolyzing hemicellulose so that it can convert xylan into xylose. Xylanase enzymes can be used in the pulp and paper industry. This study aims to determine the effect of temperature, pH on enzyme production by immobilized thermophilic bacteria using rice straw xylan extract as a substrate and to see the effect of xylanase administration on the whiteness level of inked paper waste. This study was an experimental study and used a completely randomized design (CRD). Enzyme activity was measured using a spectrophotometer at a wavelength of 540 nm. Enzyme activity data were analyzed using the ANOVA test and continued with the DMRT (Duncan Multiple Range Test) further test with a level of 5% and the whiteness of the paper was determined by testing the kappa number. The results obtained were that the temperature of immobilize thermophilic bacteria using rice straw xylan extract as a substrate affected the xylanase enzyme activity with an optimum temperature of 75°C having the highest average value of enzyme activity 4.668 U/mL. Meanwhile, the optimum pH for immobilized thermophilic bacteria to produce xylanase was pH 8.5 with the highest average value of enzyme activity 4.854 U/mL. The addition of xylanase enzyme in the fermentation process of inked paper waste was able to increase the brightness of the inked paper with a lower average value of kappa number of 2.762 compared to the higher control of 5.525.

English

The objective of the current study was to determine the silage quality of mixed rice straw silage inoculated with different concentration of Aspergillus niger. For this purpose, four experimental treatments were carried out that were based on different concentrations of Aspergillus niger per kilogram of mixed silage (80% straw + 18 wheat bran + 2% sucrose). In treatment 1, 50 mL of Aspergillus niger + 150 mL of sterile water was inoculated on mix rice straw silage (50 MRS), in treatment two, 100 mL of Aspergillus niger + 100 mL of sterile water was inoculated on mix rice straw silage (100 MRS), in treatment three, 150 mL of Aspergillus niger + 50 mL of sterile water was added on mix rice straw silage (150 MRS), while in treatment four, 200 ml of Aspergillus niger inoculant was added on mix rice straw silage (200 MRS). In control group only 200 ml of sterile water was added on mix rice straw silage (0 MRS). In all experimental treatments, the concentration of Aspergillus niger was 5.68 × 106 CFU ·mL-1. After 30 days of ensiling, all the ensiled bags of silage were opened for chemical analysis. The results showed that experimental treatments significantly increased water-soluble carbohydrate contents, dry matter, lactic acid and acetic acid (P<0.05), and reduced the pH and NH3-N/TN contents of mixed silage(P<0.05). The concentration of 100 MRS, 150 MRS, and 200 MRS significantly reduced neutral detergent fiber, crude fiber, acid detergent fiber and acid detergent lignin content of mixed silage (P<0.05). Enzyme activity results explored that carboxymethylcellulase, manganese peroxidase, laccase and xylanase enzyme activity decreased as the time of fermentation time increased. Based on the current study, it could be recommended that 100 MRS could be used to ensile rice straw because it is as efficient as other experimental treatment and it could decrease the cost of ensiling

Bioprospecting of xylanase producing fungal strains: Multilocus phylogenetic analysis and enzyme activity profiling.

The study aims to explore potential xylanase-producing indigenous fungi isolated from soil and vegetable wastes containing plant degraded matter, reporting multilocus phylogenetic analysis and xylanase enzyme activity from selective strains. Four potential xylanolytic fungi were identified through distinct primary and secondary screening of 294 isolates obtained from the samples. Morphological characterization and multigene analysis (ITS rDNA, 18S rDNA, LSU rDNA, β-tubulin, and actin gene) confirmed them as Aspergillus sp. AUMS56, Aspergillus tubingensis AUMS60 and AUMS64, and Aspergillus fumigatus AUKEMS24; achieving crude xylanase activities (through submerged fermentation using corn cobs) of 18.9, 32.29, 30.68, and 15.82 U ml-1 , respectively. AUMS60 and AUMS64 (forming lineage with A. tubingensis and Aspergillusniger in the same phylogroup with 100% Bayesian posterior probability support) secreted single xylanase (Xyn60; 36 kDa) and multiple xylanases (Xyn64A and Xyn64B; 33.4 and 19.8 kDa) respectively, having pH optima of 6.0 and exhibiting maximal activity at 60°C. These enzymes were highly stable at 40°C (120 h) and retained more than 70% activity at 50°C and at pH 5-6 (upon 72 h incubation). Our analysis suggested these enzymes to be endoxylanases demonstrating substrate hydrolysis within 15 min of reaction and maximum efficiency of xylanases from AUMS60 and AUMS64 achieving 51.1% (13 h) and 52.2% (24 h) saccharification, respectively. They also showed enhanced catalytic activity with various cations. Based on our investigation on xylan hydrolysis, we believe that these xylanases may find significant industrial applications as they have a real potential of working as a bio-catalytic cocktail (patent file number: IN E1/38213/2020-DEL) for the enhanced saccharification of lignocelluloses.

Enhancement of the enzymatic hydrolysis efficiency of wheat bran using the Bacillus strains and their consortium

In the downstream process, the bioconversion of lignocellulosic biomass can be improved by applying a biological pretreatment procedure using microorganisms to produce hydrolytic enzymes to modify the recalcitrant structure of lignocellulose. In this study, various Bacillus strains (B. subtilis B.01162 and B.01212, B. coagulans B.01123 and B.01139, B. cereus B.00076 and B.01718, B. licheniformis B.01223 and B.01231) were evaluated for the degrading capacity of wheat bran in the submerged medium using enzymatic activities, reducing sugars and weight loss as indicators. The obtained results revealed that the B. subtilis B.01162, B. coagulans B.01123 and B. cereus B.00076 could be promising degraders for the wheat bran pretreatment. Besides, the application of their consortium (the combination of 2–3 Bacillus species) showed the positive effects on cellulose bioconversion compared with monocultures. Among them, the mixture of B. subtilis B.01162 and B. coagulans B.01123 increased significantly the cellulase, endo-glucanase, and xylanase enzyme activity resulting in accelerating the lignocellulose degradation. Our results served a very good base for the development of microbial consortium for biological pretreatment of lignocellulosic raw materials.

Optimization of Agricultural Waste Substrate as an Alternative Medium for Xylan in Producing Xylanase Enzymes by Thermophilic Bacteria

Xylanase enzyme is a thermostable enzyme produced by thermophilic bacteria which in this study used Aneurinibacillus thermoaerophilus SSA2 isolates. Xylanase enzyme is able to hydrolyze xylan into xylose and xylooligosaccharides. The use of xylan in large quantities was very ineffective because of the high price and low production at this time, therefore it was necessary to find a cheaper substrate, derived from agricultural waste and potentially as an alternative to replace xylan. The purpose of this research was to find a replacable substrate of xylan from agricultural waste containing hemicellulose. Xylan of extraction results from some agricultural waste are mixed into the fermentation medium. Extraction results that produce the most optimum enzyme activity will be treated to find the optimum concentration of the substrate. This research is an experimental study using RAL, where each treatment has 5 replications. Data on the results of enzyme activity were further analyzed by ANOVA test and and continued with DMRT test at a significant level of 0,05. The results showed that the the results showed that the administration of agricultural waste substrate as a substitute for xylan affected the xylanase enzyme activity, were straw substrate had the highest average of enzyme activity at 6,033 Unit/mL and the husk substrate had the lowest average of enzyme activity at 5,667 Unit/mL. Substrate concentration had no significant effect on xylanase enzyme activity.

Characterization of xylanolytic bacteria Bacillus sp. EM24 from mangrove forest sediment, Kahyapu, Enggano Island

Xylanases are extracellular enzyme that hydrolyze xylan into xylooligosaccharide and xylose. Group bacteria that have ability to hydrolyze xylan are called xylanolytic bacteria. This study aimed to characterize xylanase produced by Bacillus sp EM24 isolated from mangrove forest sediment in Kahyapu, Enggano island. The mangrove forest sediment samples were collected from Kahyapu village, Enggano island. Isolation of bacteria was done by using 0.5% xylan beechwood agar medium. The potential xylanase producing bacteria were qualitatively investigated by using 0.5% congo red solution. Colonies which produced clear zone were presumed as xylanolytic bacteria furthermore they were selected for determination of xylanase enzyme activity. The potential xylanolytic isolates was identified by Gram staining and biochemical tests. The result of isolation showed that a total number of 30 isolates were grew well on medium. Based on clear zone screening, EM24 isolate had widest clear zone. Xylanase produced by EM24 isolate had highest activity at 40th hours after incubation with the enzyme activity of 0.484 U/mL. Characterization of xylanase measurement showed that xylanase produced by EM26 isolate can optimally work at pH 6 and temperature 35 °C. Based on identification result, EM24 isolate had close relationship with Bacillus sp.

Characterization and Identification of Xylanolytic Bacteria Stenotrophomonas sp. EL-8 Isolated from Seagrass Substrates in Enggano Island

Xylanases are hydrolytic enzymes that degraded xylan into xylooligosaccharide and xylose. Nowadays, the xylanases play a major important role in the industrial products, in the field of paper, pulp, food, beverage, pharmaceutical and animal feed. This study was to characterize and optimize xylanase produced by Stenotrophomonas sp. EL-8 isolated from the seagrass substrates in Enggano Island. The seagrass substrates were collected from Banjar Sari Beach, Enggano Island. Isolation of bacteria from seagrass substrates using 0.5% beechwood xylan agar medium. The isolates were screened by morphological characters. Colonies which produced clear zone were presumed as xylanolytic bacteria furthermore they were selected for determination of xylanase enzyme activity. The selected potential xylanolytic isolate was identify based on 16S rRNA. The results of this study showed that a total of 22 bacteria were isolated. Based on clear zone screening, EL-8 isolate indicated more potentially than the other 21 isolates. The crude enzyme production of EL-8 showed the highest activity at 18 hours incubation with the enzyme activity of 0.831 U/mL. This crude enzyme optimally worked at pH 5, temperature 45 °C with the enzyme activity 2.836 U/mL. EL-8 isolate has a close relationship with Stenotrophomonas sp. EL-8 based on 16S rRNA gene identification.

Optimización de la Producción de Xilanasa Bacteriana a Partir de Bacillus sp. K1 con el Uso de Residuos Lignocelulósicos

Las xilanasas son enzimas que hidrolizan el xilano, produciendo azúcares fermentables tales como xilosa y xilobiosa con aplicaciones industriales muy diversas entre las que destaca el biobleaching y la producción de bioetanol de segunda generación. El objetivo principal del presente estudio se enfoca en la optimización de la producción de xilanasa bacteriana por parte de la bacteria Bacillus sp. K1. La misma ha sido previamente aislada de muestras de madera en putrefacción recolectadas en las premisas de la Universidad de Lakehead para su Departamento de Biología. Las variables investigadas para la optimización fueron físicas tales como pH, temperatura y volumen de inóculo; y de composición del medio de fermentación tales como fuente de carbono, fuente de nitrógeno orgánico e inorgánico y relación porcentual entre dichos componentes. Adicionalmente, se determinó el efecto de iones metálicos (sodio, potasio, magnesio, calcio, ferroso, niqueloso, cúprico, cobaltoso y manganoso) y surfactantes (Polisorbato-20, dodecil sulfato de sodio y Triton X-100) en la actividad enzimática de la xilanasa producida. La mayor producción de xilanasa fue tras 36h de fermentación y las condiciones físicas óptimas asociadas a la producción de xilanasa fueron pH 6, temperatura 35 ºC y volumen de inóculo 1%. La composición óptima del medio de fermentación determinada está constituida por: Afrecho de trigo 4%, Glucosa 0,5%, NH4NO3 0,5%, K2HPO4 0,1%, KCl 0,1%, MgSO4 0,05%, peptona 0,5%, SDS 0,1%. La actividad enzimática generada es de 264,96±7,89 IU/L, con un 248,79% de incremento con respecto al inicial. Los inhibidores más importantes fueron los iones cúprico y manganoso con 32,00% y 49,16% de inhibición comparado con el experimento de control.

Karakterisasi Enzim Xilanase dari Isolat Bacillus sp. UJ131 di Hutan Mangrove Margasari Lampung Timur sebagai Kandidat Probiotik

<strong>Characterization of Xilanase Enzyme by Bacillus sp. UJ131 A Probiotic Candidate from the Mangrove of Margasari, East Lampung</strong>. Mangrove are known to have high biodiversity as a potential location for exploration of enzyme-producing bacteria, one of which is the xylanase enzyme. Xylanase is an enzyme that hydrolyzes the xylan-rich hemicellulose substrate. This research aims to produce and know the character of xylanase enzyme by Bacillus sp. UJ131 isolate which was isolated from the oriental shrimp in Margasari mangrove forest of East Lampung. Xylanase enzymes are produced from the bacteria by growing them in sea water complete (SWC) broth containing xylan beechwood. Characterization xylanase enzyme consist of pH, temperature, and metal ions. The results showed that xylanase had an optimal time of 18 hours with xylanase activity of 0.18 U/ml, and optimally at pH 6 and temperature 70°C. The addition of Mn2+ and Ca2+ ions increase enzyme activity, but Fe3+, Cu2+ and Mg2+ ions decrease xylanase enzyme activity. At a maximum reaction speed of 0.25 U/ml, the xylanase enzyme can produce 1.30 μM xylose per minute

Comparative 16S rDNA metagenomics study of two samples of cassava peel heap from Nigeria and India.

The microbiology of many cassava products and the wastes generated during the processing have been reported; however, majority of these reports used culture-dependent methods. This has resulted in a dearth of information on the bacterial diversity of cassava peels and peel heaps. Large amounts of cassava peels generated during the processing of cassava root are usually discharged on land or water as wastes and are allowed to rot in the open, especially in some developing countries. Culture-independent methods such as PCR-based amplification and sequencing of 16S rRNA genes, among others have been used in recent times to study the diversity of microbes in different environmental samples. In this study, bacterial isolates were screened for cellulase and xylanase enzyme activities on minimal agar and genomic DNA was isolated from cassava peel samples; metagenomics was carried out using MiSeq2 × 300 with primers specific for V3-V4 bacterial region. Samples collected from Nigeria (AAG) had more species compared with samples from India (JHA) with 793 and 525 observed OTUs (operational taxonomic units), respectively. Five bacterial isolates from cassava peel-heap samples obtained from Ogbomoso, Nigeria showed no ability to produce cellulase enzyme, seven isolates from the Nigeria samples and three from Jorhat samples were positive for xylanase production; the highest amylase activity was shown by isolate AG18 (10,055U/mL), while the lowest was recorded for isolate JA2 (2333U/mL) with a significant difference observed in the amylase activities of isolates (p ≤ 0.05). Comparing the most abundant taxonomy for each of the samples at different taxonomic levels, the most abundant for sample AAG were phylum Firmicutes (42.11%), class Bacilli (41.27%), order Lactobacillales (33.11%), family Acetobacteraceae (31.30%), genus Acetobacter (30.02%) and unclassified species of Acetobacter (29.88%), while sample JHA had Actinobacteria (47.47%) as the highest phylum and class, order Actinomycetales (47.47%), family Brevibacteriaceae (46.97%), genus Brevibacterium (46.97%) and unclassified species of Brevibacterium (46.89%). This study provides an insight into the vast diversity of the bacteria associated with cassava peel heaps and the ability of some of the bacteria to produce selected extracellular enzymes.

Potential of basidiomycetes Marasmiellus sp. and Ganoderma lucidum in xylanase enzyme production and its activity using agroindustry waste

Nowadays, agro-industrial waste such as kemiri sunan (Reutealis trisperma (Blanco) Airy Shaw) shell is abundant along with the development of biodiesel production made from kemiri sunan. The production of xylanase from kemiri sunan waste was carried out by solid state fermentation method using Basidiomycetes Marasmiellus sp and Ganoderma lucidum. Enzyme activity of xylanase was tested by measuring the amount of reducing sugar liberated from the medium by reactants using DNS method. The highest of enzyme activity resulted by fermentation using 4% of substrate concentration either by Marasmiellus sp or G. lucidum. Fermentation by Marasmiellus sp produced the highest xylanase enzyme activity amounted for 190.5 U ml−1 within 48 hours. Meanwhile, the highest enzyme activity of xylanase fermentation by G. lucidum was at the value of 121.9 U ml−1 within 72 hours and it still showed a tendency to increase.

Ozonation Pretreatment Evaluation for Xylanase Crude Extract Production from Corncob under Solid-State Fermentation

Xylanases are highly exploited enzyme in industries, including food and chemical industry. Xylanases can be utilized in catalyzing the endohydrolysis of 1,4-β-xylosidic linkages in xylan, lignocellulosic component to produce xylose-monomer. This research aims to optimize xylanase production from alternative substrate, corncob. Corncob contains 41.17% of hemicellulose, polymer of xylan. Xylanases are produced through solid state fermentation by Trichoderma viride. Ratio between substrate and moistening solution was 0.63 g/mL with fermentation temperature 32,8OC. Variables varied include incubation time and pretreatment (using autoclave, ozonation, combination of ozonation and autoclave, also without pretreatment). Xylanase activity was measured by DNS method using 1% of xylan as substrate standard. The result showed that the best incubation time is 36 h with 14403.8707 U/mg protein for specific xylanase activity by using autoclave as pretreatment. Ozonation pretreatment process can increase the enzyme activity of xylanase.

Synergetic effect of rhamnolipid from Pseudomonas aeruginosa C1501 and phytotoxic metabolite from Lasiodiplodia pseudotheobromae C1136 on Amaranthus hybridus L. and Echinochloa crus-galli weeds

Rhamnolipid (Rh) is a biosurfactant produced by the bacterial Pseudomonas aeruginosa. This present study investigates rhizospheric strain C1501 of P. aeruginosa with an accession number KF976394 with the best production of rhamnolipid: a biosurfactant. The partially purified rhamnolipid from strain C1501 and Tween 80 was tested on mycelial growth of wild strain C1136. The enzyme activities involved in biodegradation, as well as necrosis induction on the tested weeds, were performed using scanning electron microscopy. It was observed that the different concentrations of rhamnolipid tested enhanced the dry mycelia weight yield of Lasiodiplodia pseudotheobromae which has been established to be producing a phytotoxic metabolite for killing weeds. It was observed that strain C1136 had a high level of cellulase and xylanase enzyme activities during this study. The scanning electron microscopy showed that the mutant strain of C1136 combined with 0.003% v/v of rhamnolipid enhances biodegradability and a high level of necrosis on the tested weeds compared with that on the untreated weeds. The highest CMCase activities and xylanase activities were obtained on the fourth day from the phytotoxic metabolite produced from the mutant strain of L. pseudotheobromae when combined with 0.003% v/v of rhamnolipid. This study has shown that rhamnolipid can serve as an adjuvant in order to enhance the penetrability of bioherbicide active ingredient for controlling weeds.

Bioreactor Analysis for the Corn-Cob Valorization in the Xylanase Production

To achieve the optimization of the solid-state fermentation (SSF) processes where agro-industrial wastes are used, a better understanding of biological aspects (mathematical modeling) are needed, due the heterogeneity of these materials. The purpose of this study was to compare the effect of the bioreactor arrangement (Tray and Column) in the synthesis of xylanase by Rhizomucor pusillus strain in SSF process. Fermentation process was realized in both, tray and column bioreactors, using corn-cob (CC) as a carrier-substrate. Tray bioreactor and packed-bed bioreactor, containing fungal spores, 3 g of CC as substrate and support, and 8 mL of minimum Czapek-Dox culture medium; were incubated at 50 °C for 5 days. Maximal specific growth rate (μ max), maximal biomass level (X max), product/biomass yield (α) and secondary coefficient of product formation or destruction (β) were estimated by mathematical models. High value of xylanase enzyme activity (587.6 U/gds) was found in the column bioreactor. The logistic equation for cell growth and Luedeking-Piret equation for xylanase production could satisfactorily simulate the bioreactors’ kinetics data. The production of xylanase by Rhizomucor pusillus SOC-4A is affected by the type of bioreactor. Data showed that the most efficient bioreactor in production of the xylanase enzyme is the column bioreactor.

Screening of signal sequences for extracellular production of Aspergillus niger xylanase in Pichia pastoris

In this study four secretion signal sequences were evaluated for extracellular production of Aspergillus niger xylanase (XylB) in Pichia pastoris. These sequences were namely; Saccharomyces cerevisiae α-mating factor (α-MF), Human Serum Albumin (HSA), P. pastoris Acid Phosphatase (PHO1) and P. pastoris Protein with Internal Repeats (PIR1) secretion signals. The codon optimized XylB gene fused to secretion sequences was expressed under the AOX1 promoter of P. pastoris in KM71H strain. Xylanase enzyme activities for single-copy clones with α-MF, HSA, PHO1 and PIR1 as secretion sequence were 170, 123, 139 and 250U/mL, respectively, after 48h induction period. P. pastoris PIR1 leader sequence resulted highest xylanase enzyme activity at shake-flask scale among the tested secretion signal sequences. The xylanase was purified with a single step Ni-NTA purification method. The optimum temperature and pH for recombinant xylanase was 40–50°C and pH 5, respectively. Additionally, xylanase activity in purified enzyme was stable over a wide pH range (pH 3–7) and temperature of up to 50°C. Specific activity of purified xylanase was 13,271U/mg.