scholarly journals Characterization of recombinant Bacillus halodurans CM1 xylanase produced by Pichia pastoris KM71 and its potential application in bleaching process of bagasse pulp

2021 ◽  
Vol 26 (1) ◽  
pp. 15
Author(s):  
Haniyya Haniyya ◽  
Lina Mulyawati ◽  
Is Helianti ◽  
Phitsanu Pinmanee ◽  
Kanokarn Kocharin ◽  
...  

Thermoalkalophilic xylanases promise potential application in pulp biobleaching to reduce the use of toxic chlorinated chemical agents, which are harmful to the environment. In this study, a thermoalkalophilic endoxylanase gene (bhxyn3) originating from Indonesian indigenous Bacillus halodurans CM1 was cloned into yeast expression vector pPICZα A and expressed in Pichia pastoris KM71 under the control of AOX1 promoter. Recombinant P. pastoris expressed the highest final level of xylanase (146 U/mL) on BMGY medium after five days of cultivation. Optimization of xylanase production on a small scale was carried out by varying the methanol concentrations and the optimal xylanase production by the recombinant P. pastoris was observed in the culture with 2% (v/v) methanol after four days of the induction phase. The recombinant xylanase (BHxyn3E) was thermotolerant and alkalophilic, with an optimal temperature at around 55‐65 °C and under pH 8.0. The enzyme activity was slightly induced by K+, Fe2+, and MoO42‐. Enzymatic bleaching of bagasse pulp with no prior pH adjustment (pH 9) using BHxyn3E at 200 U/g oven dried pulp increased the lightness index (L*) and changed substantially the color a index (a*); however, the treatments did not change the whiteness index in a significant way. Therefore, further optimization and assessment such as adjustment of incubation temperature and pH in biobleaching were needed to reduce the use of harmful chemical agents in industrial applications.

2003 ◽  
Vol 69 (10) ◽  
pp. 6064-6072 ◽  
Author(s):  
Mônica C. Triches Damaso ◽  
Marcius S. Almeida ◽  
Eleonora Kurtenbach ◽  
Orlando B. Martins ◽  
Nei Pereira ◽  
...  

ABSTRACT Highly efficient production of a Thermomyces lanuginosus IOC-4145 β-1,4-xylanase was achieved in Pichia pastoris under the control of the AOX1 promoter. P. pastoris colonies expressing recombinant xylanase were selected by enzymatic activity plate assay, and their ability to secrete high levels of the enzyme was evaluated in small-scale cultures. Furthermore, an optimization of enzyme production was carried out with a 23 factorial design. The influence of initial cell density, methanol, and yeast nitrogen base concentration was evaluated, and initial cell density was found to be the most important parameter. A time course profile of recombinant xylanase production in 1-liter flasks with the optimized conditions was performed and 148 mg of xylanase per liter was achieved. Native and recombinant xylanases were purified by gel filtration and characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, circular dichroism spectroscopy, matrix-assisted laser desorption ionization-time of flight-mass spectrometry and physicochemical behavior. Three recombinant protein species of 21.9, 22.1, and 22.3 kDa were detected in the mass spectrum due to variability in the amino terminus. The optimum temperature, thermostability, and circular dichroic spectra of the recombinant and native xylanases were identical. For both enzymes, the optimum temperature was 75°C, and they retained 60% of their original activity after 80 min at 70°C or 40 min at 80°C. The high level of fully active recombinant xylanase obtained in P. pastoris makes this expression system attractive for fermentor growth and industrial applications.


Gold Bulletin ◽  
2021 ◽  
Author(s):  
Saeed Paidari ◽  
Salam Adnan Ibrahim

AbstractIn the past few decades, there have been remarkable advances in our knowledge of gold nanoparticles (AuNPs) and synthesizing methods. AuNPs have become increasingly important in biomedical and industrial applications. As a newly implemented method, AuNPs are being used in nanopackaging industries for their therapeutic and antibacterial characteristics as well as their inert and nontoxic nature. As with other NPs, AuNPs have privileges and disadvantages when utilized in the food sector, yet a significant body of research has shown that, due to the specific nontoxic characteristics, AuNPs could be used to address other NP flaws. In this mini review, we present synthesizing methods, food industry applications, and mechanisms of action of gold nanoparticles. Regarding the investigations, gold nanoparticles can play a major role to reduce microbial load in foodstuff and therefore can be implemented in food packaging as an effective approach.


Author(s):  
Selfela Restu Adina ◽  
Antonius Suwanto ◽  
Anja Meryandini ◽  
Esti Puspitasari

Abstract Background Lipases are promising biocatalysts for industrial applications and attract attention to be explored. A novel acidic lipase has been isolated from the lipolytic bacteria Micrococcus luteus EMP48-D (LipEMP48-D) screened from tempeh. The lipase gene had previously been overexpressed in Escherichia coli BL21, but the expression level obtained was relatively low. Here, to improve the expression level, the lipase gene was cloned to Pichia pastoris. We eliminated the native signal sequence of M. luteus and replaced it with α-mating factor (α-MF) signal sequence. We also optimized and synthesized the lipase gene based on codon preference in P. pastoris. Results LipEMP48-D lipase was expressed as an extracellular protein. Codon optimization has been conducted for 20 codons, with the codon adaption index reaching 0.995. The highest extracellular lipase activity obtained reached 145.4 ± 4.8 U/mg under AOX1 promoter in P. pastoris KM71 strain, which was 9.7-fold higher than the previous activity in E. coli. LipEMP48-D showed the highest specific activity at pH 5.0 and stable within the pH range 3.0–5.0 at 40 °C. LipEMP48-D also has the capability of hydrolyzing various long-chain triglycerides, particularly olive oil (100%) followed by sunflower oil (88.5%). LipEMP48-D exhibited high tolerance for various polar organic solvents with low log P, such as isopropanol (115.7%) and butanol (114.6%). The metal ions (Na+, K+, Ca2+, Mg2+, Mn+) decreased enzyme activity up to 43.1%, while Fe2+ increased relative activity of enzymes up to 200%. The conversion of free fatty acid (FFA) into fatty acid methyl ester (FAME) was low around 2.95%. Conclusions This study was the first to report overexpression of Micrococcus lipase in yeast. The extracellular expression of this acidic lipase could be potential for biocatalyst in industrial fields, especially organic synthesis, food industry, and production of biodiesel.


Author(s):  
Girisha Malhotra ◽  
Shilpa S. Chapadgaonkar

Abstract Background Xylanase is one of the widely applied industrial enzymes with diverse applications. Thermostability and alkali tolerance are the two most desirable qualities for industrial applications of xylanase. In this paper, we reveal the statistical Taguchi optimization strategy for maximization of xylanase production. The important process parameters pH, temperature, concentration of wheat bran, and concentration of yeast extract were optimized using the Taguchi L8 orthogonal array where the 4 factors were considered at 2 levels (high and low). Results The optimized conditions given by model were obtained as follows: (i) pH 6, (ii) culture temperature 35 °C, (iii) concentration of xylan 2% w/v, (iv) concentration of wheat bran 2.5% w/v. The production was scaled upto 2.5 L bioreactor using optimized process parameters. A high xylanase titer of 400 U/ml could be achieved in less than 60 h of culture in the reactor. Conclusion Optimization was successful in achieving about threefold increase in the yield of xylanase. The optimized conditions resulted in a successful scale up and enhancement of xylanase production.


2019 ◽  
Vol 141 (7) ◽  
Author(s):  
Peter Ostermeier ◽  
Annelies Vandersickel ◽  
Stephan Gleis ◽  
Hartmut Spliethoff

Gas–solid fluidized bed reactors play an important role in many industrial applications. Nevertheless, there is a lack of knowledge of the processes occurring inside the bed, which impedes proper design and upscaling. In this work, numerical approaches in the Eulerian and the Lagrangian framework are compared and applied in order to investigate internal fluidized bed phenomena. The considered system uses steam/air/nitrogen as fluidization gas, entering the three-dimensional geometry through a Tuyere nozzle distributor, and calcium oxide/corundum/calcium carbonate as solid bed material. In the two-fluid model (TFM) and the multifluid model (MFM), both gas and powder are modeled as Eulerian phases. The size distribution of the particles is approximated by one or more granular phases with corresponding mean diameters and a sphericity factor accounting for their nonspherical shape. The solid–solid and fluid–solid interactions are considered by incorporating the kinetic theory of granular flow (KTGF) and a drag model, which is modified by the aforementioned sphericity factor. The dense discrete phase model (DDPM) can be interpreted as a hybrid model, where the interactions are also modeled using the KTGF; however, the particles are clustered to parcels and tracked in a Lagrangian way, resulting in a more accurate and computational affordable resolution of the size distribution. In the computational fluid dynamics–discrete element method (CFD–DEM) approach, particle collisions are calculated using the DEM. Thereby, more detailed interparticulate phenomena (e.g., cohesion) can be assessed. The three approaches (TFM, DDPM, CFD–DEM) are evaluated in terms of grid- and time-independency as well as computational demand. The TFM and CFD–DEM models show qualitative accordance and are therefore applied for further investigations. The MFM (as a variation of the TFM) is applied in order to simulate hydrodynamics and heat transfer to immersed objects in a small-scale experimental test rig because the MFM can handle the required small computational cells. Corundum is used as a nearly monodisperse powder, being more suitable for Eulerian models, and air is used as fluidization gas. Simulation results are compared to experimental data in order to validate the approach. The CFD–DEM model is applied in order to predict mixing behavior and cohesion effects of a polydisperse calcium carbonate powder in a larger scale energy storage reactor.


2017 ◽  
Vol 13 (2) ◽  
pp. 191
Author(s):  
Anak Agung Istri Ratnadewi ◽  
Moch. Yoris Alidion ◽  
Agung Budi Santoso ◽  
Ika Oktavianawatia

<p>Endo-β-1,4-D-xylanase is a hydrolytic enzyme that breakdown the 1.4 chain of xylan polysaccharide. We have succes to transform the plasmid pET-Endo gene encoding endo-1,4-β-D-xylanase from Bacillus sp. originally from termites abdominal to E. coli BL21. The clone was ready for large scale of enzyme production. To reduce production cost, we look for subtitute media for the expensive Luria Berthani broth. Chicken guts broth is good alternative while rich of protein and very cheap. The content of N dissolved chicken guts broth reaches 87 % of LB broth. Growth of E. Coli BL21 in Chicken guts broth and LB broth (as control) was observed by Optical Density (OD) using spectrofotometer. Concentration of glucose added in broth and incubation temperature was varied. The result showed that optimal growth was in addition of 1.5 % glucose and incubated at  37 <sup>o</sup>C for 16 h. This optimal condition was used to grow E. coli BL21 pET-Endo for xylanase production. Enzyme purification was done by Ni-NTA affinity chromatography. Highest protein yield was 0.076 mg/mL obtained in 100 mM imidazole elucidation. The activity and specific activity of xylanase were estimated as 0.042 U/mL and 0.556 U/µg, respectively. The purification factor was 3.16 time and the molecular weight of enzyme was ± 30, 000 Dalton</p>


Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 352 ◽  
Author(s):  
Xue Lv ◽  
Chuang Liu ◽  
Zhubao Shao ◽  
Shulin Sun

Hydrogels with high mechanical strength are needed for a variety of industrial applications. Here, a series of hydrogels was prepared by introducing hybrid particles as hydrophobic association points to toughen the hydrogels. These toughened hydrogels were able to transfer an external mechanical force via the reorganization of the crosslinking networks. They exhibited an extraordinary mechanical performance, which was the result of the coordination between hydrophobic segments and hybrid particles. Herein, the connection between the dissipated energy of the inner distribution structure (on a small scale) and the mechanical properties (on a large scale) was conducted. Specifically, we inspected hydrogels of latex particles (LPs) with different chain lengths (C4, C12, C18) and studied their inner structural parameters, namely, the relationship between the density and molecular weight of crosslinking points to the mechanical strength and energy dissipation. Favorable traits of the hydrogels included compact internal structures that were basically free from defects and external structures with puncture resistance, high toughness, etc. Based on the experimental results that agreed with the theoretical results, this study provides a profound understanding of the internal structure of hydrogels, and it offers a new idea for the design of high-strength hybrid hydrogels.


Author(s):  
C. Bharatiraj ◽  
JL Munda ◽  
Ishan Vaghasia ◽  
Rajesh Valiveti ◽  
P. Manasa

The DC motors an outstanding portion of apparatus in automotive and automation industrial applications requiring variable speed and load characteristics due to its ease of controllability. Creating an interface control system for multi DC motor drive operations with centralized speed control, from small-scale models to large industrial applications much demand. By using Lab VIEW (laboratory virtual instrument engineering workbench) as the motor controller, can control a DC motor for multiple purposes using single software environment. The aim of this paper is to propose the centralized speed control of DC motor using Lab VIEW. Here, the Lab VIEW is used for simulating the motor, whereas the input armature voltage of the DC motor is controlled using a virtual Knob in Lab VIEW software. The hardware part of the system (DC motor) and the software (in personal computer) are interfaced using a data acquisition card (DAQ) -Model PCI- 6024E. The voltage and Speed response is obtained using LABVIEW software. Using this software, group of motors’ speed can be controlled from different location using remote telemetry. The propose work also focuses on controlling the speed of the individual DC motor using PWM scheme (Duty cycle based Square wave generation) and DAQ. Help of the DAQ along with Lab VIEW front panel window, the DC motor speed and directions can be change easily in remote way. In order to test the proposed system the laboratory model for an 80W DC motor group (multi drive) is developed for different angular displacements and directions of the motor. The simulation model and experimental results conforms the advantages and robustness of the proposed centralized speed control.


Author(s):  
Dominik Scholtes ◽  
Stefan Seelecke ◽  
Gianluca Rizzello ◽  
Paul Motzki

Abstract Within industrial manufacturing most processing steps are accompanied by transporting and positioning of workpieces. The active interfaces between handling system and workpiece are industrial grippers, which often are driven by pneumatics, especially in small scale areas. On the way to higher energy efficiency and digital factories, companies are looking for new actuation technologies with more sensor integration and better efficiencies. Commonly used actuators like solenoids and electric engines are in many cases too heavy and large for direct integration into the gripping system. Due to their high energy density shape memory alloys (SMA) are suited to overcome those drawbacks of conventional actuators. Additionally, they feature self-sensing abilities that lead to sensor-less monitoring and control of the actuation system. Another drawback of conventional grippers is their design, which is based on moving parts with linear guides and bearings. These parts are prone to wear, especially in abrasive environments. This can be overcome by a compliant gripper design that is based on flexure hinges and thus dispenses with joints, bearings and guides. In the presented work, the development process of a functional prototype for a compliant gripper driven by a bistable SMA actuation unit for industrial applications is outlined. The focus lies on the development of the SMA actuator, while the first design approach for the compliant gripper mechanism with solid state joints is proposed. The result is a working gripper-prototype which is mainly made of 3D-printed parts. First results of validation experiments are discussed.


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