Extraction and purification of tannase by reverse micelle system

Optimization of production conditions, isolation, purification, and characterization of tannase from filamentous fungi

Tannase-producing filamentous fungi residing alongside tannin-rich ambient in the Northwest Himalayas were isolated at laboratory conditions and further identified by 18S ribosomal RNA gene sequencing. Five most potent tannase producing strains (EI ≥ 2.0), designated Aspergillus fumigatus AN1, Fusarium redolens AN2, Penicillium crustosum AN3, Penicillium restrictum AN4, and Penicillium commune AN5, were characterized. The strain Penicillium crustosum AN3 exhibited a maximum zone dia (25.66 mm ± 0.38). During solid-state fermentation, a maximal amount of tannase was attained with Penicillium crustosum AN3 using pine needles (substrate) by adopting response surface methodology for culture parameter optimization. Gel filtration chromatography yielded 46.48% of the partially purified enzyme with 3.94-fold of tannase purification. We found two subunits in enzyme-117.76 KDa and 88.51 KDa, respectively, in the SDS-PAGE. Furthermore, the characterization of partially purified tannase revealed a maximum enzyme activity of 8.36 U/mL at 30 °C using a substrate concentration (methyl gallate) of 10 mM. To broaden the knowledge of crude enzyme application, dye degradation studies were subjected to extracellular crude tannase from Penicillium crustosum AN3 where the maximum degradation achieved at a low enzyme concentration (5 ppm).

Microemulsions as nano-reactors for the solubilization, separation, purification and encapsulation of bioactive compounds

Bioactive components possess various functionalities and are most interested for different food, nutraceutical and pharmaceutical formulations. The current review will discuss the preparation methods and fabrication techniques to design microemulsions (MEs) for the solubilization, separation, encapsulation and purification of various agro-food bioactive compounds. ME systems have shown suitable potential in enhancing oil recovery, protein extraction, and isolation of bioactive compounds. Moreover, the capability of ME based systems as drug and nutraceutical delivery cargos, and synthesis of various organic and inorganic nanoparticles, especially using biopolymers, will be investigated. ME liquid membranes are also developed as nano-extractor/nano-reactor vehicles, capable of simultaneous extraction, encapsulation or even synthesis of hydrophilic and lipophilic bioactive compounds for food, nutraceutical and drug applications.

Application of experimental designs and response surface methods in screening and optimization of reverse micellar extraction

Reverse micellar extraction (RME) has emerged as a versatile and efficient tool for downstream processing (DSP) of various biomolecules, including structural proteins and enzymes, due to the substantial advantages over conventional DSP methods. However, the RME system is a complex dependency of several parameters that influences the overall selectivity and performance of the RME system, hence this justifies the need for optimization to obtain higher possible extraction results. For the last two decades, many experimental design strategies for screening and optimization of RME have been described in literature. The objective of this article is to review the use of different experimental designs and response surface methodologies that are currently used to screen and optimize the RME system for various types of biomolecules. Overall, this review provides the rationale for the selection of appropriate screening or optimization techniques for the parameters associated with both forward and backward extraction during the RME of biomolecules.

Influence of different parameters on reverse micelle extraction combined with acetone precipitation to purify sn-1,3 extracellular lipase from Aspergillus niger GZUF36

There are few reports on the feasibility of combined reverse micelle extraction and acetone precipitation to obtain electrophoretic pure enzymes. We aimed to purify a sn-1,3 extracellular lipase from a novel Aspergillus niger GZUF36 through this combination in this work. This lipase preliminarily purified by controlling the volume ratio (1:2.5) of crude enzyme solution and acetone. Then, we studied effects of different parameters on reverse micelle extraction. The suitable surfactant, pH, salt and cosolvent and extraction time for forward extraction were 125 mM cetyl trimethylammonium bromide (CTAB), 9.0, 0.075 M NaCl, 10% n-hexanol and 30 min, respectively. Under these conditions, the forward extraction rate reached 90.3% ± 3.2%. The suitable salt, pH, extraction time and short chain alcohol for backward extraction were consecutively 1.5 M KCl, 6.5, 60 min and 10% ethanol. Adding 10% ethanol shows a significant advantage of improvement the extraction rate. Under these optimal conditions, the total extraction rate and purification factor of lipase reached 76.8% and 10.14, respectively. SDS-PAGE showed that molecular weight of the pure protein was 42.7 kDa and TLC exhibited sn-1,3 selectivity of this lipase. LC-MS/MS analysis revealed that the lipase had 297 amino acid residues and was likely to glycosylate. Through the study of different parameters, it demonstrated that the new and simple combination of reverse micelle extraction using CTAB as surfactant and n-hexanol as cosolvent for forward extraction and adding ethanol for backward extraction and acetone precipitation is a promising method to get almost an electrophoretically pure sn-1,3 lipase.

Cationic reverse micellar based purification of recombinant glutaminase free L-asparaginase II of Bacillus subtilis WB800N from fermentation media

Reverse micellar extraction (RME), a liquid-liquid based separation is a versatile tool for protein purification. A statistical approach was employed for the purification of recombinant glutaminase free anti-cancerous enzyme viz., l-asparaginase II to evaluate the effects of RME in current study. The cationic system (CTAB/iso-octane/hexanol/butanol) was used in RME to optimize both forward and backward protein extraction efficiency. By adapting Taguchi's orthogonal array (OA), maximum forward extraction efficiency (FEE) of 86.98% with 84.82% enzyme activity recovery and 1.04 times purification fold achieved with the optimized parameters. Under the optimal levels, the back extraction efficiency (BEE) was observed to be 96.97% with 93.07% enzyme activity recovery and 1.38 times purification fold. Further, mass transfer kinetic studies of RME indicated the mass transfer coefficients of forward and backward extraction to be 0.049 min^-1 and 0.036 min^-1 respectively.

Reverse micelle Extraction of Antibiotics using an Eco-friendly Sophorolipids Biosurfactant

Reverse micelles extraction of erythromycin and amoxicillin were carried out using the novel Sophorolipids biosurfactant. By replacing commonly used chemical surfactants with biosurfactant, reverse micelle extraction can be further improved in terms of environmental friendliness and sustainability. A central composite experimental design was used to investigate the effects of solution pH, KCl concentration, and sophorolipids concentration on the reverse micelle extraction of antibiotics. The most significant factor identified during the reverse micelle extraction of both antibiotics is the pH of aqueous solutions. Best forward extraction performance for erythromycin was found at feed phase pH of approximately 8.0 with low KCl and sophorolipids concentrations. Optimum recovery of erythromycin was obtained at stripping phase pH around 10.0 and with low KCl concentration. On the other hand, best forward extraction performance for amoxicillin was found at feed phase pH around 3.5 with low KCl concentration and high sophorolipids concentration. Optimum recovery of erythromycin was obtained at stripping phase pH around 6.0 with low KCl concentration. Both erythromycin and amoxicillin were found to be very sensitive toaqueous phase pH and can be easily degraded outside of their stable pH ranges.

Application of aqueous biphasic systems as strategy to purify tannase from Aspergillus tamarii URM 7115

The aims of the current study are to assess the influence of polyethylene glycol (PEG) concentration, molar mass, pH, and citrate concentrations on aqueous biphasic systems based on 2⁴ factorial designs, as well as to check their capacity to purify tannase secreted by Aspergillus tamarii URM 7115. Tannase was produced through submerged fermentation at 26°C for 67 h in Czapeck-Dox modified broth and added with yeast extract and tannic acid. The factorial design was followed to assess the influence of PEG molar mass (M_PEG 600; 4,000 and 8,000 g/ mol), and PEG (C_PEG 20.0; 22.0 and 24.0% w/w) and citrate concentrations (C_CIT 15.0, 17.5, and 20.0%, w/w), as well as of pH (6.0, 7.0, and 8.0) on the response variables; moreover, partition coefficient (K), yield (Y), and purification factor (PF) were analyzed. The most suitable parameters to purify tannase secreted by A. tamarii URM 7115 through a biphasic system were 600 (g/mol) M_PEG, 24% (w/w) C_PEG, 15% (w/w) C_CIT at pH 6.0 and they resulted in 6.33 enzyme partition, 131.25% yield, 19.80 purification factor and 195.08 selectivity. Tannase secreted by A. tamarii URM 7115 purified through aqueous biphasic systems composed of PEG/citrate can be used for industrial purposes, since it presents suitable purification factor and yield.

Molecular interaction mechanisms in reverse micellar extraction of microbial transglutaminase

Reverse micellar extraction is an efficient and economical alternative for protein purification. In this study, microbial transglutaminase (MTGase) from crude materials was purified using reverse micellar extraction, and the molecular interaction mechanism in reverse micellar extraction of MTGase was explored. By using a molecular simulation study, the interaction mechanism of forward extraction was investigated. The molecular simulation results reveal the interaction of MTGase-water-surfactant is the major driving force for the forward extraction. Further, the effect of ionic strength on molecular interactions in backward extraction was investigated using 1H low-field nuclear magnetic resonance (LF-NMR) and circular dichroism (CD) spectra. In backward extraction, the interactions between water and the other two molecules (MTGase and surfactant molecules) are enhanced while the interactions between target molecules (MTGase) and the other two molecules (water and surfactant molecules) are weakened as the ionic strength increases. Moreover, the effect of size exclusion on backward extraction was also investigated. The results demonstrate size exclusion has limit effect at high ionic strength, and the weakened interaction of MTGase-water-surfactant is the main reason causing the release of the target molecules in backward extraction. This work might provide valuable reference to the MTGase purification and downstream processing.

Influence of pH and salt concentration on functional properties of walnut protein from different extraction methods

The effect of pH and NaCl on solubility and functional properties of walnut proteins obtained through AOT reverse micelles, enzyme-assisted reverse micelles and aqueous phase extraction methods was investigated and compared. Extraction yield, foaming properties, water holding capacities of protein obtained through enzyme-assisted reverse micelles at pH 2-12 and NaCl concentration 0.1-1 M were significantly higher than those of the AOT reverse micelles and aqueous phase extracted two. The solubility of proteins by AOT reverse micelles and enzyme-assisted reverse micelles at certain pH and NaCl concentration had no significant difference, but was higher that of the aqueous buffer. Oil holding capacity of three proteins was 2.35, 3.96 and 1.08 cm³/g, respectively. At pH 6-12 and NaCl concentration 0.1-1 M, the emulsifying activity of protein from AOT reverse micelles was higher than those of other two methods, while the emulsifying stability of protein from enzyme-assisted reverse micelles was the highest. The functional properties of walnut proteins were affected by extraction methods. It indicated that the walnut protein might be potentially applied in food industry as a food ingredient.

Reverse micellar extraction of bromelain from pineapple peel--Effect of surfactant structure

Pineapple peel is generally disposed or used as compost. This study was focused on extracting bromelain from pineapple peel by using reverse micelles. It was found that gemini surfactant C12-8-C12·2Br (octamethylene-α,ω-bis(dimethyldodecylammonium bromide)) showed distinctive advantage over its monomeric counterpart DTAB (dodecyl trimethyl ammonium bromide); under optimized condition, the bromelain extracted with C12-8-C12·2Br reverse micelle had an activity recovery of 163% and a purification fold of 3.3, while when using DTAB reverse micelle, the activity recovery was 95% and the purification fold was 1.7. Therefore, the spacer of gemini surfactant should play a positive role in bromelain extraction and may suggest the potential of gemini surfactant in protein separation since it has been so far rarely used in relative experiments or technologies.

Interaction of tannase from Aspergillus niger with polycations applied to its primary recovery

The interaction of tannase (TAH) with chitosan, polyethyleneimine and Eudragit(®)E100 was studied. It was found that TAH selectively binds to these polycations (PC), probably due to the acid nature of the target protein. TAH could interact with these PC depending on the medium conditions. The effect of the interaction on the secondary and tertiary structure of TAH was assayed through circular dichroism and fluorescence spectroscopy. TAH was recovered from Aspergillus niger culture broth by means of precipitation and adsorption using chitosan.