Optimization of xylanase from Pseudomonas mohnii isolated from Simlipal Biosphere Reserve, Odisha, using response surface methodology

Abstract

Background Xylanase has long been recognized as a widely used industrially important enzyme. There are some bacterial species already reported to produce xylanase which have potent xylanolytic activity towards the use of this enzyme in the production of bioethanol from lignocellulosic biomass. In this view, an efficient xylanolytic bacterial strain was isolated and screened from the soil sample of Simlipal Biosphere Reserve. Enzymatic assay for the xylanase activity was evidenced from the most potent bacterial strain, and the culture condition was optimized for obtaining the maximum enzyme activity. The most potent xylanolytic strain was also identified using biochemical and molecular methods. Results Nineteen xylanolytic bacteria (SXB1-SXB19) were isolated from Simlipal forest soil samples following dilution plate technique using corn cob xylan-enriched nutrient agar medium and screened for their xylanase-producing ability. Among these isolates, SXB19 showed maximum xylanolytic potential with a halozone size of 2.5 cm as evident in the formation of prominent yellow patches surrounding its growth in xylan-enriched nutrient agar plate. In unoptimized condition, SXB19 showed the highest enzymatic activity of 22.5 IU/ml among the 19 bacterial strains. In order to optimize the culture conditions for maximizing the xylanase production, Box-Behnken design of response surface methodology (RSM) was used. Four variables such as incubation time, pH, substrate (corn cob xylan) concentration, and temperature were considered for the RSM optimization study. From the results, it is evident that in an optimized condition of incubation time 36 h, pH 6.0, xylan concentration 0.5%, and temperature 42.5 °C, the enzyme activity reached a maximum of 152 IU/ml with nearly 6.75 times increase from the unoptimised condition. Besides, xylanase production from SXB19 was considerable in the presence of xylan followed by starch, nitrogen source such as urea followed by yeast extract, and mineral ion sources such as KCl followed by MgSO4 and ZnSO4. From different biochemical tests, 16S rRNA gene sequencing, and phylogenetic analysis, the bacterial strain SXB19 was identified as Pseudomonas mohnii. Conclusion The isolation of Pseudomonas mohnii, a potent xylanolytic bacterium from Simlipal, is a new report which opens up an opportunity for industrial production of xylanase for bioethanol production and other applications. Graphical abstract

Xylanolytic Biotechnological Applications of Extracellular Xylanase Isolated from Marine Bacillus Subtilis AKM1

“…Temperature is an important parameter for xylanase production, in this investigation, the maximal yield was achieved at 40 ℃ with (2.232 U/ml) activity, and activity of (2.15 U/ml) at 35 °C was then followed as shown in gure 5. this was supported by some previous work showed the same optimum incubation temperature for xylanase produced by Pseudomonas Mohini 57 and Streptomyces olivaceus (MSU3) 44 ,while being so close to other studies to be recorded at 35 ℃ for xylanases produced by Bacillus licheniformis 60 , Bacillus subtilis BS04 55 andBacillus tequilensis strain ARMATI 58 . However, the xylanase secreted by Bacillus tequilensis strain UD-3 was optimum at 50°C 25 .…”

“…of incubation for Bacillus pumilus SV-205 24 andStreptomyces olivaceus(MSU3) 44 ,while being at 36 hrs. for Pseudomonas mohini 57 .…”

Co-elicitation of lignocelluloytic enzymatic activities and metabolites production in an Aspergillus-Streptomyces co-culture during lignocellulose fractionation

“…Xylanases catalyze the hydrolysis of xylans and have been widely studied in filamentous fungi such as Aspergillus ( Betini et al., 2009 ; Pal and Khanum, 2010 ). Aspergillus xylanases have been ( Paul et al., 2020 ) widely used in several industrial processes such as paper pulp biobleaching ( Sridevi et al., 2016 ). Waste management programs make use of xylanases so as to hydrolyze xylan found in industrial and municipal wastes ( Motta et al., 2013 ).…”

Engineered yeasts and lignocellulosic biomaterials: shaping a new dimension for biorefinery and global bioeconomy

“…Bacteria from the phyla Actinobacteria [ 145 , 146 ], Proteobacteria [ 147 ], and Bacillota also produce many cellulases [ 148 ]. Cellulases isolated from bacteria include β-1,4-endoglucanase from Cellulomonas telluris [ 149 ], Bacillus and γ-Protobacteria [ 133 ]; Cellulose 1,4-beta-cellobiosidase from Sporocytophaga myxococcoides and Cohnella sp [ 150 ]; and xylanase from Pseudomonas mohnii [ 151 ].…”