Effect of xylanase immobilisation conditions by combination of entrapment and covalent binding on alginate beads

The immobilisation of enzymes offer improvement in enzyme stability and characteristics as well as overcome the limitations of free enzyme systems for commercial purposes. In the current study, xylanase was immobilised using a combination technique of entrapment and covalent binding within and onto calcium alginate beads. The sodium alginate and calcium chloride (CaCl2) concentration used for the preparation of alginate beads which is the support matrix for xylanase immobilisation were fixed at 3% (w/v) and 0.3 M, respectively. The effect of immobilisation conditions (agitation rate, enzyme loading, and glutaraldehyde concentration) were studied using One-Factor-At-a-Time (OFAT) approach. The best condition for optimum immobilisation yield (83.93%) was found to be made up of the following parameter combination: agitation rate, 200 rpm; xylanase loading, 200 U; and glutaraldehyde concentration, 12% (w/w). The study shows the immobilisation conditions play a significant role towards the immobilisation yield of xylanase

Immobilisation of xylanase for xylooligosaccharides production from meranti wood sawdust

The limitations of free or soluble enzyme such as non-reusability, poor stability, and sensitivity to denaturation could be handled by the use of immobilised enzymes. Generating a value-added product, xylooligosaccharides (XOS) from new renewable material, Meranti wood sawdust (MWS) by the used of immobilised xylanase are currently an object of interest due to their benefits over soluble xylanase. The aim of this study is to immobilise xylanase for XOS production from MWS by enzymatic hydrolysis. Xylan from MWS was extracted using a standard chlorite holocellulose method. Prior to enzymatic hydrolysis, immobilised xylanase was prepared using a different technique of immobilisation comprised of a single entrapment, single covalent binding, and a combination of entrapment and covalent binding. The immobilisation conditions were optimised using a systematic experimental design which includes one-factor-at-a-time (OFAT) to study the effects of each parameter, followed by fractional factorial design (FFD) used for screening process to determine the significant parameters, and finally, optimisation by response surface methodology (RSM) to obtain maximum xylanase immobilisation yield. The results showed that xylan content in MWS was 21.89% and the recovery yield of xylan after extraction was 39.45% of original xylan available in MWS. For the immobilisation of xylanase, a combination technique of entrapment and covalent binding showed the highest immobilisation yield (65.83%) compared to single techniques which yielded only 31.98% and 48.46%, respectively. The optimum xylanase immobilisation conditions by RSM were obtained at 16.76% (w/w) of glutaraldehyde concentration, 3.13% (w/v) of sodium alginate concentration, and 178 U of enzyme loading with a maximum immobilisation yield of 82.61%. Immobilisation improved the pH stability from 7.0 to 8.0 and thermal stability by shifting the optimum temperature from 50 to 60 °C. Thermodynamic study indicated that immobilised xylanase slightly lowered the Ea from 15.24 to 14.80 kJ∙mol−1, which improves the catalytic efficiency of xylanase. The immobilised xylanase also exhibited a good operational stability, retaining about 81% and 60% of its initial activity during the second and third process cycles. The optimised immobilised xylanase then was applied in enzymatic hydrolysis to degrade the MWS xylan and the production of total XOS and its derivatives were compared to the reaction of free xylanase with commercial xylan. The highest total XOS yield obtained from MWS xylan by the reaction of immobilised xylanase was 53.61 mg/g at their best hydrolysis conditions at 2% (w/v) of substrate concentration, 48 h of hydrolysis, and 55 °C. During hydrolysis, the immobilised xylanase released a lower degree of polymerisation (DP) of XOS, mainly xylobiose (X2), xylotriose (X3), and xylotetraose (X4) from the degradation of MWS xylan, which are the preferable types of oligomers, particularly for food industry applications. From the reusability study, immobilised xylanase in the XOS production was able to retain 70% of its initial XOS production during the second cycle with five consecutive cycles. With respect to economic feasibility and industrial application, the MWS demonstrated the potential as a new source of xylan substrate for XOS production. Immobilised xylanase by a combination technique also showed good results in terms of stability and recycling efficiency for continuous hydrolysis

Effects of Support Matrix for Xylanase Immobilisation on Alginate Hydrogel Beads

Enzymes serving as biocatalysts and play an important roles in many industrial field. However, the limitation of enzyme usage due to its high cost and unstable conditions of Enzymes serving as biocatalysts and play an important roles in many industrial field. However, the limitation of enzyme usage due to its high cost and unstable conditions of soluble enzyme to harsh conditions lead to findings an alternative to enhance the enzyme efficiency by immobilisation (insoluble enzyme). The present work reported a combination of immobilisation technique of xylanase by entrapment and covalent binding on alginate hydrogel beads. Xylanase enzyme was effectively immobilised within the support matrix, alginate hydrogel beads by entrapment and covalent binding on the surface of beads using glutaraldehyde as a cross-linked agent. The effects of support matrix comprised of sodium alginate concentration (% w/v) and calcium chloride, CaCl2 (M) were studied in order to obtain a better immobilisation yield. The suitable concentration of sodium alginate and CaCl2 to ensure a robust and stable hydrogel beads with higher immobilisation yield were formed as a support matrix for xylanase immobilisation. The analysis of xylanase activity was determined using dinitrosalicyclic (DNS) acid reagent method. Maximal enzyme immobilisation yield (>80 %) was achieved at 3.0 % w/v of sodium alginate concentration and 0.3 M of CaCl2. The study shows the support matrix of hydrogel beads gave a significant impact towards the immobilisation yield of xylanase

Combination of Entrapment and Covalent Binding Techniques for Xylanase Immobilisation on Alginate Beads: Screening Process Parameters

Xylanase are responsible enzyme for hydrolysis of xylan into many beneficial products such as xylose, xylitol and xylooligosaccharides. Due to industrial potential of xylanase, a large number of studies have become interested in their immobilisation to reduce the cost of enzyme. Immobilised enzymes are currently the object of interest due to its benefits over soluble or free enzyme applied in enzymatic hydrolysis. The aims of this study were to determine the suitable method for xylanase immobilisation and to identify the significant parameter which affecting the immobilisation yield by fractional factorial design (FFD). Immobilised xylanase was prepared using a single immobilisation techniques of entrapment and covalent binding and also a combination of entrapment and covalent binding techniques. The immobilisation conditions for xylanase which includes of sodium alginate concentration, calcium chloride concentration, agitation rate and enzyme loading were screened using FFD experimental design to determine the most significant parameters in affecting the efficiency of immobilised xylanase. The analysis of xylanase activity was determined using dinitrosalicyclic acid (DNS) method. The xylanase enzyme was successfully immobilised by entrapment in sodium alginate beads and covalent binding on the surface of beads by glutaraldehyde. The combination of entrapment and covalent binding showed the highest immobilisation yield of 65.81 % compared to a single technique which contributes only 31.99 % and 48.53 %. Glutaraldeyhde concentration showed the most significant parameters compared to the others parameter which gives about 69.01 % of contribution on the xylanase immobilisation yield. The study shows the efficiency of enzyme immobilisation could be improved by a combination of immobilisation techniques and determination of the most significant factors for xylanase immobilisation

Effects of Support Matrix for Xylanase Immobilisationon Alginate Hydrogel Beads

Enzymes serving as biocatalysts and play an important roles in many industrial field. However, the limitation of enzyme usage due to its high cost and unstable conditions of soluble enzyme to harsh conditions lead to findings an alternative to enhance the enzyme efficiency by immobilisation (insoluble enzyme). The present work reported a combination of immobilisation technique of xylanase by entrapment and covalent binding on alginate hydrogel beads. Xylanase enzyme was effectively immobilised within the support matrix, alginate hydrogel beads by entrapment and covalent binding on the surface of beads using glutaraldehyde as a cross-linked agent. The effects of support matrix comprised of sodium alginate concentration (% w/v) and calcium chloride, CaCl2(M) were studied in order to obtain a better immobilisation yield. The suitable concentration of sodium alginate and CaCl2 to ensure a robust and stable hydrogel beads with higher immobilisation yield were formed as a support matrix for xylanase immobilisation. The analysis of xylanase activity was determined using dinitrosalicyclic (DNS) acid reagent method. Maximal enzyme immobilisation yield (>80%) was achieved at 3.0% w/v of sodium alginate concentration and 0.3M of CaCl2. The study shows the support matrix of hydrogel beads gave a significant impact towards the immobilisation yield of xylanase

Production of High Commercial Value Xylooligosaccharides from Meranti Wood Sawdust Using Immobilised Xylanase

The present study explores the utilisation of a new raw material from lignocellulose biomass, Meranti wood sawdust (MWS) for high commercial value xylooligosaccharides (XOS) production using immobilised xylanase. The xylanase was immobilised by a combination of entrapment and covalent binding techniques. The hemicellulosic xylan from MWS was extracted using a standard chlorite delignification method. The production of total and derivatives of XOS from the degradation of the hemicellulosic xylan of MWS were compared to the production from the commercial xylan from Beechwood. The utilisation of the extracted xylan from MWS yielded 0.36 mg/mL of total XOS after 60 h of hydrolysis. During the hydrolysis reaction, the immobilised xylanase released a lower degree of polymerisation (DP) of XOS, mainly X2 and X3, which were the major products of xylan degradation by xylanase enzymes. The production of XOS with a lower DP from MWS demonstrated the biotechnological potential of the MWS in the future. The XOS production retained about 70% of its initial XOS production during the second cycle. This is also the first report on the utilisation of MWS wastes in enzymatic hydrolysis using immobilised xylanase for XOS production

Optimization of fresh palm oil mill effluent biodegradation with Aspergillus niger and Trichoderma virens

In this work, response surface optimization strategy was employed to enhance the biodegradation process of fresh palm oil mill effluent (POME) by Aspergillus niger and Trichoderma virens. A central composite design (CCD) combined with response surface methodology (RSM) were employed to study the effects of three independent variables: inoculum size (%), agitation rate (rpm) and temperature (°C) on the biodegradation processes and production of biosolids enriched with fungal biomass protein. The results achieved using A. niger were compared to those obtained using T. virens. The optimal conditions for the biodegradation processes in terms of total suspended solids (TSS), turbidity, chemical oxygen demand (COD), specific resistance to filtration (SRF) and production of biosolids enriched with fungal biomass protein in fresh POME treated with A. niger and T. virens have been predicted by multiple response optimization and verified experimentally at 19% (v/v) inoculum size, 100 rpm, 30.2°C and 5% (v/v) inoculum size, 100 rpm, 33.3°C respectively. As disclosed by ANOVA and response surface plots, the effects of inoculum size and agitation rate on fresh POME treatment process by both fungal strains were significant