Tarun Kanti Bandyopadhyay

Classification, mode of action and production strategy of xylanase and its application for biofuel production from water hyacinth

Xylanases are classified under glycoside hydrolase families which represent one of the largest groups of commercial enzymes. Depolymerizing xylan molecules into monomeric pentose units involves the synergistic action of mainly two key enzymes which are endo-β-xylanase and β-xylosidase. Xylanases are different with respect to their mode of action, substrate specificities, biochemical properties, 3D structure and are widely produced by a spectrum of bacteria and fungi. Currently, large scale production of xylanase can be produced through the application of genetic engineering tool which allow fast identification of novel xylanase genes and their genetic variations makes it an ideal enzymes. Due to depletion of fossil fuel, there is urgent need to find out environment friendly and sustainable energy sources. Therefore, utilisation of cheap lignocellulosic materials along with proper optimisation of process is most important for cost efficient ethanol production. Among, various types of lignocellulosic substances, water hyacinth, a noxious aquatic weed, has been found in many tropical. Therefore, the technological development for biofuel production from water hyacinth is becoming commercially worthwhile. In this review, the classification and mode of action of xylanase including genetic regulation and strategy for robust xylanase production have been critically discussed from recent reports. In addition various strategies for cost effective biofuel production from water hyacinth including chimeric proteins design has also been critically evaluated.

Rapid development of xylanase assay conditions using Taguchi methodology

ABSTRACT The present investigation is mainly concerned with the rapid development of extracellular xylanase assay conditions by using Taguchi methodology. The extracellular xylanase was produced from Aspergillus niger (KP874102.1), a new strain isolated from a soil sample of the Baramura forest, Tripura West, India. Four physical parameters including temperature, pH, buffer concentration and incubation time were considered as key factors for xylanase activity and were optimized using Taguchi robust design methodology for enhanced xylanase activity. The main effect, interaction effects and optimal levels of the process factors were determined using signal-to-noise (S/N) ratio. The Taguchi method recommends the use of S/N ratio to measure quality characteristics. Based on analysis of the S/N ratio, optimal levels of the process factors were determined. Analysis of variance (ANOVA) was performed to evaluate statistically significant process factors. ANOVA results showed that temperature contributed the maximum impact (62.58%) on xylanase activity, followed by pH (22.69%), buffer concentration (9.55%) and incubation time (5.16%). Predicted results showed that enhanced xylanase activity (81.47%) can be achieved with pH 2, temperature 50°C, buffer concentration 50 Mm and incubation time 10 min.

Optimization of physical and morphological regime for improved cellulase free xylanase production by fed batch fermentation using Aspergillus niger (KP874102.1) and its application in bio-bleaching

ABSTRACT The physiological and morphological changes were extensively studied during fed batch fermentation using newly isolated Aspergillus niger (KP874102.1). Significantly higher xylanase production was possible through optimization of environmental stresses by fed batch process. The fed batch fermentation was carried out for improved xylanase production (2524 U) where initial xylan was kept 1.5 g/L in the production medium. However, 3 g/L of xylan with 50 mM K2HPO4 having pH-7 was consecutively fed at 72 and 120 h of fermentation. K2HPO4 showed significant role both the morphology of the microorganism and produces enzymes in fed batch fermentation. During feeding phase, the pH was found in the range of 6.5 to 7 which was used as marker for the fed batch process. The crude enzyme was used for the bio-bleaching of banana pulp.

Isolation, screening and characterization of a novel extracellular xylanase from Aspergillus niger (KP874102.1) and its application in orange peel hydrolysis

In the present work, a potent xylanase producing fungal strain Aspergillus niger (KP874102.1) was isolated through cultural and morphological observations from soil sample of Baramura forest, Tripura west, India. 28S rDNA technique was applied for genomic identification of this fungal strain. The isolated strain was found to be phylogenetically closely related to Aspergillus niger. Kinetic constants such as Km and Vmax for extracellular xylanase were determined using various substrate such as beech wood xylan, oat spelt xylan and CM cellulose through Lineweaver-Burk plot. Km, Vmax and Kcat for beech wood xylan are found to be 2.89mg/ml, 2442U and 426178Umlmg-1 respectively. Crude enzyme did not show also CM cellulose activity. The relative efficiency of oat spelt xylan was found to be 0.819 with respect to beech wood xylan. After acid hydrolysis, enzyme was able to produce reducing sugar with 17.7, 35.5, 50.8 and 65% (w/w) from orange peel after 15, 30, 45 and 60min incubation with cellulase free xylanase and maximum reducing sugar formation rate was found to be 55.96μg/ml/min. Therefore, the Aspergillus niger (KP874102.1) is considered as a potential candidate for enzymatic hydrolysis of orange peel.

Characterization, genetic regulation and production of cyanobacterial exopolysaccharides and its applicability for heavy metal removal

Cyanobacteria are uniquely suited for the development of sustainable bioproduction platforms but are currently underutilized due to lack of genetic tools. Exopolysaccharide (EPS) is of significant biotechnological importance due to their technological application in various industries. It has been found that most of the research works are focused on isolation and characterization of new exopolysaccharides from microbial sources. The exopolysaccharides from cyanobacteria have been poorly explored despite their original structural features associated with specific biological and physicochemical properties. However, it could increase in a near future through the use of inexpensive cyanobacterial platform as well as available information on the structural data and specific properties of these biopolymers. This review covers genetic regulation for production of exopolysaccharide, analytical strategies for their characterization, evaluation of structure property relationship and design of extraction protocol from cyanobacterial biomass. In addition applications of exopolysaccharide for removal of heavy metal from wastewater are critically reviewed.

Performance improvement of microbial fuel cell (MFC) using suitable electrode and Bioengineered organisms: A review

ABSTRACT There is an urgent need to find an environment friendly and sustainable technology for alternative energy due to rapid depletion of fossil fuel and industrialization. Microbial Fuel Cells (MFCs) have operational and functional advantages over the current technologies for energy generation from organic matter as it directly converts electricity from substrate at ambient temperature. However, MFCs are still unsuitable for high energy demands due to practical limitations. The overall performance of an MFC depends on microorganism, appropriate electrode materials, suitable MFC designs, and optimizing process parameters which would accelerate commercialization of this technology in near future. In this review, we put forth the recent developments on microorganism and electrode material that are critical for the generation of bioelectricity generation. This would give a comprehensive insight into the characteristics, options, modifications, and evaluations of these parameters and their effects on process development of MFCs.

Bioremediation and Detoxification Technology for Treatment of Dye(s) from Textile Effluent

The aim of this chapter is to demonstrate the technical and economic feasibility of an inte‐ grated process for microbial treatment of dye(s) containing wastewater from textile efflu‐ ent that evaluates the efficiency and effectiveness to meet the dye(s)’ maximum contaminant level. This chapter covers the whole process of microbial treatment methods that are adopted for dye removal to make an eco-friendly system. The purpose of this treatment technology includes process modifications and engineering approaches. It comprises existing technologies with new advancement technology at all stages of the process. This chapter evaluates the reliability of technologies for small and large systems to make the system cost-effective. It also demonstrates how genetically engineered micro‐ organism works and shows that the “microbial treatment platform for dye removal” can operate with positive economical balance to economize the bioprocess technology. Thus, future prospects of microbial treatment technology should be directed not only how to economically improve bioremediation but also how to effectively commercialize such economically sounded “bio-based” treatment methods in different industries.

GAS-NON-NEWTONIAN LIQUID FLOW THROUGH ELBOWS

Experimental investigations have been carried out to evaluate the two-phase pressure drop across different types of elbows in the horizontal plane for gas-non-Newtonian pseudoplastic liquid flow. A generalised correlation have been developed to predict The two-phase pressure drop as a function of various physical and dynamic variables of the system. Statistical analysis of the correlation suggests that the correlation is of acceptable accuracy.

Gas‐Non‐Newtonian liquid flow through helical coils—pressure drop and CFD analysis

The problem of determining the pressure losses in helical coil is important in design and analysis of the fluid machinery. It is well known that when a fluid flows through a curved pipe, the flow pattern becomes more complex than that of a straight pipe because of the generation of secondary flows due to the interaction between centrifugal and viscous forces. To understand the interaction between the two‐phase gas‐ non‐Newtonian liquid flow through helical coil tube, hydrodynamic modeling is being performed with a commercial computational fluid dynamics (CFD) code—FLUENT 6.3. The modeling has attempted to describe the results of flow visualization experiments performed in transparent helical coil tube. Both phases are first treated separately as homogeneous. Coupling is achieved through pressure and interphase exchange coefficients. Multiphase model Eulerian‐Eulerian, viscous non‐Newtonian laminar power law model is used to describe the interaction between the phases. The CFD modeling is compared with the...

Water and air‐water flow through U‐bends—experiments and CFD analysis

Experimental investigation has been carried out in order to study the water and air‐water flow through four different U‐bends. Numerical modeling is carried using Fluent 6.3 software to find its applicability.