Xylanase Enzyme Research Articles

Synergism of enzymes in chemical pulp bleaching from an industrial point of view: A critical review

AbstractEnzymes are biological catalysts and are very specific, catalyzing either a single chemical reaction or a limited number of closely related reactions. For example, xylanases are enzymes that catalyze the cleavage of polymeric xylan and thereby break down this hemicellulose. The first xylanase enzyme preparations used in the bleaching process of chemical pulp also contained cellulase, which catalyzes the hydrolysis of cellulose. This obviously had an adverse effect on pulp yield and quality. Unfortunately, this setback gave enzyme‐assisted pulp bleaching a negative reputation. At a later stage, enzyme producers managed to engineer enzyme production strains that generated cellulase‐free xylanase preparations. However, due to the initial negative experiences with the earlier enzyme mixtures, only a limited number of companies in the pulp industry have seriously considered using these so‐called second‐generation enzymes in their bleach plants. It is apparent that these improved enzyme preparations would bring about significant benefits in terms of chemical cost savings and effluent quality. In addition to xylanase‐aided bleaching, it is possible to improve the effectivity further by adding other enzymes, such as lipase and esterase, to create an enzyme cocktail. This may be particularly beneficial in the bleaching of hardwood pulp, such as white birch, which often encounters complex and troublesome problems with wood extractives. By adding different types of enzymes at more than one position in the fiberline, even further improvements are possible. The main objective of this review is to discuss the advantages of incorporating modern enzyme preparations in the bleaching of chemical pulp.

Searching for Versatile Polysaccharide-Degrading Alkali-tolerant or Alkaliphilic Bacillus Strains

The plant-derived polysaccharides (Cellulose, xylose and amylose, etc.) are the most abundant renewable raw materials in nature. Cellulose and xylose are the predominant carbohydrate polymer components of the plant cell walls and the most abundant biopolymers in the world. Another plant-derived polysaccharide, starch is found in plant tubers, roots and seed endosperms as a major carbohydrate reserve. In this study, it was aimed to find multi-enzyme producer bacteria strains in terms of industrially important enzymes such as cellulase, xylanase and amylase. For this purpose, isolated Bacillus strains from different samples were qualitatively evaluated for cellulase, xylanase and amylase enzyme production potentials. The isolates that have the highest enzyme activity were selected for biochemical tests, molecular and phenotypic characterization. As a result of these characterization process, SB57, SB104, SB155, SB178, SB197 and SB199 strains were identified as Bacillus pumilus and SB118, SB138 strains were identified as Bacillus safensis. In addition to these strains, SB120 and SB147 strains were identified as Bacillus aerius and Bacillus licheniformis respectively. 16S rDNA sequence analysis results of these Bacillus strains were deposited in NCBI GenBank® under accession number KT371465 - KT371474 respectively.

Effects of palm oil supplementation and fibrolytic enzymes in high forage diets on growth, carcass characteristics and fatty acid profiles of lambs

This study investigated the effects of palm oil and fibrolytic enzyme supplementation in high forage diets on growth, carcass characteristics and fatty acid composition of lambs. Forty South African Mutton Merino ram lambs were randomly assigned to four treatment groups (n = 10 lambs/ treatment) and fed a basal total mixed ration (TMR). The treatments were: TMR diet with Megalac as bypass oil (control); TMR diet supplemented with 3% palm oil; TMR diet with cellulase and xylanase enzymes and TMR diet supplemented with 3% palm oil and cellulase and xylanase enzymes. The lambs were slaughtered at a target weight of about 42 kg. Palm oil supplementation resulted in a longer feeding period (P < 0.05) and lower dressing percentage (P < 0.01), but the carcasses had higher meat yield (P < 0.01) and lower fat content (P < 0.05) compared to the other treatment groups. Additionally, palm oil supplementation increased the proportion of C18:0 (P < 0.05) while decreasing (P < 0.05) the proportion of C14:0 (P < 0.05) and C16:0 (P < 0.05) in fat depots, which may be beneficial for human health. The fibrolytic enzyme treatment had minimal effects on growth, carcass characteristics, meat quality and fatty acid composition of lambs. The interaction effect of palm oil and fibrolytic enzymes had positive effects on the UFA: SFA ratio due to an increase (P < 0.05) in C20:3n6 and C20:4n6 and a reduction (P < 0.05) in saturated fatty acids. The results suggest that methane mitigation strategies through palm oil and enzyme supplementation can be used in lamb diets without adverse effects on product quality.

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.

Biochemical and Molecular Dynamics Study of a Novel GH 43 α-l-Arabinofuranosidase/β-Xylosidase From Caldicellulosiruptor saccharolyticus DSM8903.

The complete hydrolysis of xylan can be facilitated by the coordinated action of xylanase and other de-branching enzymes. Here, a GH43 α-l-arabinofuranosidase/β-xylosidase (CAX43) from Caldicellulosiruptor saccharolyticus was cloned, sequenced, and biochemically investigated. The interaction of the enzyme with various substrates was also studied. With a half-life of 120 h at 70°C, the produced protein performed maximum activity at pH 6.0 and 70°C. The enzyme demonstrated a higher activity (271.062 ± 4.83 U/mg) against para nitrophenol (pNP) α-L-arabinofuranosides. With xylanase (XynA), the enzyme had a higher degree of synergy (2.30) in a molar ratio of 10:10 (nM). The interaction of the enzyme with three substrates, pNP α-L-arabinofuranosides, pNP β-D-xylopyranosides, and sugar beet arabinan, was investigated using protein modeling, molecular docking, and molecular dynamics (MD) simulation. During the simulation time, the root mean square deviation (RMSD) of the enzyme was below 2.5 Å, demonstrating structural stability. Six, five, and seven binding-interacting residues were confirmed against pNP α-L-arabinofuranosides, pNP β-D-xylopyranosides, and arabinan, respectively, in molecular docking experiments. This biochemical and in silico study gives a new window for understanding the GH43 family’s structural stability and substrate recognition, potentially leading to biological insights and rational enzyme engineering for a new generation of enzymes that perform better and have greater biorefinery utilization.

Screening of microorganisms for hydrolyases with commercial potential

Advancement in green chemistry has increased the use of microbial hydrolyases in various industries and chemical processes because of high catalytic efficiency, specificity, cost-effectiveness and eco-friendly nature. Bioconversion of tannins such as tannic acid is achieved by tannin acyl hydrolase, also known as tannase. It converts tannic acid into glucose and gallic acid by catalyzing the hydrolysis of ester and depside linkages in tannic acid. Tyrosinase is monophenol and O-diphenol oxidase a copper containing enzyme catalyzes the oxidation of tyrosine and generates different types of pigment such as melanin. Xylanases hydrolyze xylan into its constituent sugar with the help of several debranching enzymes. Microbial strains isolated from various sources were screened for these hydrolyases: Bhavnagar marine salterns (Bacillus megaterium BVUC_01 and Bacillus licheniformis BVUCh_02); Okhamadhi marine salterns Aspergillus versicolor; Spoiled/infected pomegranate (Xenoacremonium falcatum, two strains PGF1 and PGF4, Bacillus velezensisPGF2 and Candida freyschussiiPGF3. The other laboratory maintained bacterial cultures namely, Bacillus subtilis, Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella typhi were also used in this study. Asp. versicolor and Xen. falcatum (PGF1) produced all the three enzymes (tannase, tyrosinase and xylanase). B. licheniformis, B. megaterium, B. subtilis, B. velezensis produced tyrosinase and xylanase. Xen. falcatum (PGF4) and PGF2 produced tannase and xylanase. PGF3 produced tannase and tyrosinase. While, Bacillus megaterium and Salmonella typhi showed only tyrosinase activity. Candida freyschussii showed tannase activity. Staphylococcus aureus did not produce any of these enzymes.

Physico-mechanical characterization of poly (butylene succinate) and date palm fiber-based biodegradable composites

The main objective of this research was to study the influence of an enzymatic treatment process of date palm fibers on their chemical and morphological properties as well as the physical and mechanical characteristics of composites filled with raw and treated fibers. To this end, three extraction approaches were considered (a combination of xylanase and pectinase enzymes, xylanase enzymes followed by a pectinase one and pectinase enzyme followed by xylanase). Chemical and morphological analyses were performed on raw and treated fibers. The tensile test of the manufactured composites was achieved, using extrusion and injection molding process. These composites were also subjected to water absorption tests. The results showed that non-cellulosic components decreased after enzymatic treatments while the cellulose content increased significantly. The scanning electron microscope morphological analyses showed that the extraction with the combination of these enzymes is very effective as a fibrillation phenomenon. Composites with high rigidity were observed in the case of enzymatically treated fibers. These composites reveal a better moisture resistance compared to the untreated fibers.

Sweet Orange (Citrus sinensis) Peel Powder with Xylanase Supplementation Improved Growth Performance, Antioxidant Status, and Immunity of Broiler Chickens

The global population is estimated to reach approximately 9.7 billion persons by 2050. To meet the demands of the growing population, highly valuable feedstuffs that have traditionally been included as staples in poultry diets (e.g., corn and soybeans) are being reallocated for human nutrition purposes. As the availability of conventional poultry feedstuffs has decreased, poultry nutritionists are investigating the potential use of nonconventional feedstuffs in poultry diets. The objective of this study was to investigate the effects of utilizing dried sweet orange (Citrus Sinensis) peel powder (with and without xylanase supplementation) as a nonconventional feedstuff on production and health parameters in broiler chickens. A total of 375-day-old male Cobb 500 chicks were weighed and blocked for their initial body weight and randomly assigned to 25 pens (15 birds/pen). Dietary treatments were randomly and independently applied to each pen (5 replicates/per treatment). The following five dietary treatments were investigated in this study: 1) CON: basal corn-soya diet, 2) OPP3: basal diet containing 3% orange peel powder, 3) OPP5: basal diet containing 5% orange peel powder, 4) OPP3ENZ: OPP3 diet with xylanase enzyme added (50g/metric ton) and 5) OPP5ENZ: OPP5 diet with xylanase enzyme added (50g/metric ton). Feed intake and body weight were recorded on a weekly basis. Blood samples were collected at the end of the trial and analyzed for antioxidant and immune-related metabolites. The weights of internal organs (including immunological organs) were collected and reported. The data were statistically analyzed using PROC MIXED in SAS (SAS 9.4). Regardless of xylanase supplementation, the OPP-fed birds had decreased feed intakes and improved feed efficiency than the birds that received the control treatment (P=0.01). Significantly reduced Malondialdehyde (MDA) levels in the blood in all OPP-fed groups (P=0.01) compared to the CON group, but relative thymus weight was increased in the OPP5ENZ group. In conclusion, the inclusion of OPP in the broiler chicken diet (up to 5% of DMI) with xylanase enzyme supplementation could improve antioxidant capacity and cellular immune responses, positively impacting production.

Decomposition of Maize Straw between Two Phosphate Solubilizing Fungi: Aspergillus Niger and Penicillium Chrysogenum

Aspergillus niger (A. niger) and Penicillium chrysogenum (P. chrysogenum) can significantly promote the degradation of maize straw and phosphorus release. Compared with P. chrysogenum, A. niger is more efficient in maize straw degradation and phosphorus releasing. After seven days of incubation, the highest degradation ratio and phosphorus content in A. niger+maize straw treatment is 2.58% and 2.3 mg/L, respectively. The mechanisms for maize straw decomposition between these two fungi are different. Oxalic acid is the primary organic acid secreted by A. niger, which is more function in the decomposition of maize straw compared with propionic acid secreted by P. chrysogenum. In addition, A. niger has higher acidic xylanase and lignin peroxidase enzymes activities, which is conducive to the degradation of more stable substances in maize straw, i.e., lignin. This study indicated that A. niger is the primary candidate for the reuse of crop straw in the way of return to the field.

Effect of barley straw and Egyptian clover hay on the rumen fermentation and structure and fibrolytic activities of rumen bacteria in dromedary camel.

Background and Aim:Understanding the regulations of rumen microbiota and their fibrolytic capabilities under different forages are essential to improve rumen fermentation and animal feed efficiency. This study aimed to evaluate the changes in the rumen fermentation and the structure and fibrolytic activities of rumen bacteria in camels fed barley straw and Egyptian clover hay.Materials and Methods:Three fistulated camels were fed a diet containing barley straw for 30 days; then transitioned to a diet containing Egyptian clover hay for 30 days. In addition, bacterial media enriched with xylan and different cellulose sources, namely, filter paper, wheat straw, and alfalfa hay, were used to evaluate the ability of camel rumen bacteria to produce xylanase and cellulase enzymes.Results:The camel group fed Egyptian clover hay showed higher crude protein intake, rumen ammonia, total volatile fatty acids, and acetic acid. Moreover, the camel group fed barley straw showed higher neutral detergent fiber intake, rumen pH, and propionic and butyric acids. Principal component analysis showed that bacterial communities were separated based on the forage type. Forage type affected the composition of rumen bacteria and most of the bacterial community was assigned to phylum Bacteroidetes and Firmicutes. Egyptian clover hay diet increased the proportions of genus Prevotella and Ruminococcus; while fed barley straw diet increased the Butyrivibrio, RC9_gut_group, and Fibrobacteres. The bacterial culture of the Egyptian clover hay fed group produced the greatest xylanase and the bacterial culture of the barley straw fed group produced the maximum cellulase.Conclusion:Egyptian clover hay is recommended to feed camels in intensive production. Moreover, the bacterial community in the camel rumen is a promising source of lignocellulolytic enzymes.

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&lt;0.05), and reduced the pH and NH3-N/TN contents of mixed silage(P&lt;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&lt;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

The effect of surfactant on the hydrolysis of coconut husk using cellulase and xylanase enzyme immobilized on chitosan magnetic nanoparticles

This study aimed to investigate the effect of surfactant Tween 80 in the enzymatic hydrolysis of coconut husks by using immobilized cellulase from Aspergillus niger, Trichoderma reesei, and immobilized xylanase. Surfactant is common to enhance the yield of sugar in enzymatic process. However, its application in immobilized enzymes has not been well investigated. Coconut husk is an abundant resource of cellulose that can be converted to reducing sugar which can be utilized to produce various products such as biofuel, lactic acid, 5-hydroxymethyl furfural, and leluvinic acid. Chitosan magnetic nanoparticles as a support in the immobilization process were prepared using the coprecipitation method to obtain particles separated by magnetic field. Cellulase and xylanase were immobilized on magnetic particles through covalent bond directly and with Glutaral dialdehyde (GDA) as cross-linker. The immobilized cellulase and xylanase along with Tween 80 surfactants were applied for the hydrolysis of NaOH pre-treated coconut husk at 55°C for 48 hours. The reducing sugar content were identified with DNS methods. In this study, the highest reducing sugar content obtained from cellulase from A niger, cellulase from T reesei and xylanase were 0.412 mg/ml, 0.532 mg/mL and 1.166 mg/mL, respectively. The concentration of Tween 80 that yielding highest sugar concentration for immobilized cellulase from A niger, cellulase from T reesei and xylanase were 2%, 1% and 2% (w/v), respectively.

Lignocellulosic Ezymes of Basidial Fungi-Isolated from Different Ecological Niches of Georgia

Great interest in basidiomycetes for targeted technological treatment of agro-industrial plant substrates are conditioned by their ability to produce lignocellulosic enzymes. Consisting of 29 soil-climatic zones, Georgia (South Caucasus area) represents a unique place for the isolation of microorganisms. In order to study the biochemistry and physiology of wood-degrading basidiomycetes, samples of wood-degrading basidiomycetes were collected from different taxonomic niches of Georgia. 45 strains were obtained as pure cultures and 32 ones – identified. Producers of lignocellulosic enzymes were revealed among test fungi under solid-state and submerged cultivation conditions. Pleurous ostreatus GV10, Pleurotus drynus IN 11 and Fomes fomentarius GK33 were found to be the best producers of cellulosic enzymes using orange and mandarin peels, wheat and Potato straw, wheat bran as substrates, and Ganoderma lucidum GB03 – the best producer of laccase during cultivation on orange and mandarin peels waste. The influence of lignocellulose on the accumulation of the enzymes laccase, xylanase and Filter paper assay was studied.

Lignocellulosic Ezymes of Basidial Fungi-Isolated from Different Ecological Niches of Georgia

Great interest in basidiomycetes for targeted technological treatment of agro-industrial plant substrates are conditioned by their ability to produce lignocellulosic enzymes. Consisting of 29 soil-climatic zones, Georgia (South Caucasus area) represents a unique place for the isolation of microorganisms. In order to study the biochemistry and physiology of wood-degrading basidiomycetes, samples of wood-degrading basidiomycetes were collected from different taxonomic niches of Georgia. 45 strains were obtained as pure cultures and 32 ones – identified. Producers of lignocellulosic enzymes were revealed among test fungi under solid-state and submerged cultivation conditions. Pleurous ostreatus GV10, Pleurotus drynus IN 11 and Fomes fomentarius GK33 were found to be the best producers of cellulosic enzymes using orange and mandarin peels, wheat and Potato straw, wheat bran as substrates, and Ganoderma lucidum GB03 – the best producer of laccase during cultivation on orange and mandarin peels waste. The influence of lignocellulose on the accumulation of the enzymes laccase, xylanase and Filter paper assay was studied.

Enzymatic Bioprospecting of Fungi Isolated from a Tropical Rainforest in Mexico.

The humid tropical environment provides an ideal place for developing a high diversity of plants; this is why it is an interesting site for the enzymatic bioprospecting of fungi that are responsible for the recycling of organic matter in an efficient and accelerated way and whose enzymes could have multiple biotechnological applications. For this study, 1250 isolates of macroscopic and microscopic fungal morphotypes were collected from soil, leaf litter, and wood. One hundred and fifty strains (50 from each source) were selected for the enzymatic screening. From the first phase, 51 strains with positive activity for laccase, protease, amylase, xylanase, and lipase enzymes were evaluated, of which 20 were isolated from leaf litter, 18 from the soil, and 13 from wood. The 10 best strains were selected for the enzymatic quantification, considering the potency index and the production of at least two enzymes. High laccase activity was detected for Trametes villosa FE35 and Marasmius sp. CE25 (1179 and 710.66 U/mg, respectively), while Daedalea flavida PE47 showed laccase (521.85 U/mg) and protease activities (80.66 U/mg). Fusarium spp. PH79 and FS400 strains had amylase (14.0 U/mg, 49.23 U/mg) and xylanase activities (40.05 U/mg, 36.03 U/mg) respectively. These results confirm the enzymatic potential of fungi that inhabit little-explored tropical rainforests with applications in industry.

Spectral analysis and kinetic studies of enzymatic delignification of kraft wood pulp by xylanase

The traditional bleaching methods used chlorine as bleaching agent which produced large amount of chlorinated organic compounds including dioxins which are persistent environmental pollutants. The alternate methods using peroxides and enzymes were developed to achieve total chlorine free bleaching. The xylanase enzyme was used as bleaching agent in this study. The delignification study was performed to evaluate the optimum conditions required for obtaining minimum kappa number of the pulp to remove maximum lignin from the wood fibres. The interactions of various factors such as pulp consistency, enzyme dosage and temperature were studied. The best conditions for enzymatic bleaching obtained were 10% consistency, 50 IU of enzyme dosage and 52oC in the range studied. The predicative mathematical models were developed for enzymatic bleaching. The activation energy for xylanase delignification of paper pulp was 13.989kJ/mol. The significant functional groups in bleached pulp samples were analysed using Fourier transform infrared spectroscopy and the surface morphology of pulp fibres was studied using Scanning electron microscopy images.

Purification and Characterization of Thermostable Alkaline Xylanase by Aspergillus terreus from Elephant Dung

Aims: Purification and characterization of xylanase by Aspergillus terreus isolated from elephant dung.&#x0D; Study Design: Xylanase enzyme produced by A. terreus was extracted from the fermented solid medium using solid state fermentation and purified using chromatographic techniques. The purified enzyme was characterized for physio-chemical and kinetic properties.&#x0D; Place and Duration of Study: Experiments were performed at the School of Biotechnology, Devi Ahilya University, Indore, INDIA and Maharaja Ranjit Singh College of Professional Sciences, Indore, INDIA, between June, 2019 and September, 2021.&#x0D; Methodology: The enzyme was extracted and purified using ammonium sulphate precipitation, ion exchange chromatography using DEAE cellulose and gel filtration chromatography (GFC) using Sephadex G-200. The molecular weight of the purified enzyme was determined using native poly acrylamide gel electrophoresis (Native PAGE) and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). The purified enzyme was characterized to determine pH and temperature optima. Thermostability, pH stability and substrate kinetics were studied for purified xylanase. Effect of several metal ions and detergents were also studied.&#x0D; Results: The alkali-thermo xylanase of Aspergillus terreus was purified to 14.6-fold with a 39.48% recovery through IEC on DEAE-cellulose and GFC using Sephadex G-200. The purified enzyme had a specific activity, 111.6 U/mg. The SDS-PAGE revealed that the enzyme was monomeric with a molecular weight of 87 kDa. The optimum pH and temperature were 8 and 60⁰C, respectively. The Km and Vmax values of the partially purified xylanase were found to be 0.016 mg/l and 102.64 U/mg protein, respectively with birch wood xylan as substrate.&#x0D; Conclusion: The enzyme was active over a wide pH range of 6-11 and temperature range of 40⁰C to 80ºC, indicating its alkali tolerant and thermostable characteristics which is the requirement of different industries. Several ions namely Zn2+ enhanced xylanase activity by 187% followed by Ca2+ (129%), Mg2+ (123%), NH4+ (146%) and Fe3+ (118%) at 10 mM concentration. However, Cu2+ and Hg2+ completely inhibited xylanase activity. This research provides the basis for application of xylanase and improves its biotechnological potential in mainly in paper pulp industry, biofuel generation and in bread baking.

Evaluation of bamboo water-retting for fiber bundle extraction

Bamboo fiber bundles were successfully extracted from bamboo culms using water-retting, taking advantage of enzymes secreted by microorganisms in the retting liquid. The harvest year and place of origin of the bamboo and the source of water impacted the products of the retting process. One-month-old bamboo was decomposed completely, whereas the one-year-old sample was hardly changed after 24-day retting. Moisture regain and crystallinity varied with the different origins of the bamboo. However, all samples resulted in similar chemical structures and thermal properties. The best operational conditions for water-retting were 3-month-old bamboo from Wuxi incubated in deionized water. Enzyme activities, including cellulase, xylanase, pectinase, and ligninolytic enzymes (lignin peroxidase, manganese peroxidase, and laccase) were monitored during a 24-day retting. Manganese peroxidase was the primary enzyme used to degrade lignin, resulting in absorbance at 294 nm of UV-Vis spectra. In addition, xylanase played a leading role in hydrolyzing hemicellulose, which was consistent with the change in reducing sugar yield. In addition, variations in dissolved oxygen and pH values were also recorded, indicating the changes in bacterial strains and the enzymatic system. The wastewater from bamboo retting showed good biodegradability but a lack of nitrogen and phosphorus. Overall, a manganese peroxidase–xylanase combined enzyme-retting treatment would offer a more environmentally friendly approach for extracting bamboo fibers.

Determination of Total Xylanase Activities of Various Thermophilic Bacteria

Enzymes, which have important metabolic functions in living organisms, make important contributions to human beings by using them for different purposes in many areas such as economy, food, agriculture, and industry as part of the daily lives. Today, enzymes, whose production and usage purposes, are increasing, were generally obtained from plant, animal, and microorganisms. In this study; the enzyme producing isolates and their total xylanase activities of various thermophilic bacteria (Bacillus coagulans, Bacillus licheniformis, Bacillus subtilis, Bacillus sp. and Geobacillus kaustophilus) isolated from previously hot springs in Eastern and Southeastern Anatolia regions were determined. In the enzyme activity of the isolates, 47 isolates showed xylanase activity less than 0.1 U/ml, 31 isolates were between 0.1 U/ml and 0.2 U/ml. However, 5 isolates of B. subtilis [BTX3 (0.206 U/ml), BTX6 (0.286 U/ml), BTX22 (0.2 U/ml), BTX27 (0.203 U/ml) and BTX32 (0.206 U/ml)] were exhibited highest activity for xylanase enzyme production.

The effect of feed enzymes phytase, protease and xylanase on pelleting of microalgal biomass

Lower energy consumption for producing feed pellets is an important part of the economy in the feed mill. The same is if physical pellet quality is degraded. The interest in using of novel ingredients is increasing due to requirements for the sustainable development goals. Defatted microalgae as by-product from biodiesel production is one of many novel ingredients. The purpose of this experiment was to understand how the addition of small amount of enzymes can reduce the flow resistance in the die during pellet discharge, without affecting the physical quality of pellets. Thus, possibly reduce the total consumption of electrical energy during compaction. Three enzymes, phytase, protease, xylanase, and combinations of those were added to defatted Desmodesmus subspicatus microalgae at 3 inclusion levels. Feed enzymes xylanase and phytase helped lowering the flow resistance of the material in the die. Reduction of flow resistance was in average 17 times lover when all three levels of enzyme phytase were used. The same was observed when 0.01% xylanase was added. All feed enzymes and their combination have evidently lowered underwater pellet swelling due to their hydrolytic activity at the surface of the microalgal particles. The hydrolytic activities of the feed enzymes did not affect hardness of the microalgal pellets. Contact angle degree between pellet surface and oil droplet was lowered when xylanase and protease was used at all three dosage levels. However, contact angle degree between pellet surface and water droplets was unaffected by the hydrolytic activity of enzymes.