A Novel L-Asparaginase from Enterobacter sp. Strain M55 from Maras Salterns in Peru

L-Asparaginase (ASNase) is used in medicine for neoplasms treatment and in food industry for mitigation of acrylamide in high-temperature processed food. In medicine, commercial ASNases have exhibited side effects and l-glutaminase (GLNase) activity affecting the clinical treatment. The aim of this work was to study a novel ASNase from Enterobacter sp. M55 isolated from Maras Salters in Peru, which was purified and biochemically characterised. This ASNase exhibited a Km of 5.71 mM and a Vmax of 0.16 µmol mL–1 min–1, as well as an optimum temperature and pH of 37 °C and 6, respectively. Moreover, a good activity (80 %) was observed at physiological pH. Likewise, the enzyme increased its activity by around 50% in presence of urea, glutathione, and glucose. Whilst in presence of serum compounds, it kept more that 60 % of activity. In addition, this ASNase showed low GLNase activity

Chemical and structural changes of pretreated empty fruit bunch (EFB) in ionic liquid-cellulase compatible system for fermentability to bioethanol

The pretreatment of empty fruit bunch (EFB) was conducted using an integrated system of IL and cellulases (IL-E), with simultaneous fermentation in one vessel. The cellulase mixture (PKC-Cel) was derived from Trichoderma reesei by solid-state fermentation. Choline acetate [Cho]OAc was utilized for the pretreatment due to its biocompatibility and biodegradability. The treated EFB and its hydrolysate were characterized by the Fourier transform infrared spectroscopy, scanning electron microscopy, and chemical analysis. The results showed that there were significant structural changes in EFB after the treatment in IL-E system. The sugar yield after enzymatic hydrolysis by the PKC-Cel was increased from 0.058 g/g of EFB in the crude sample (untreated) to 0.283 and 0.62 ± 06 g/g in IL-E system after 24 and 48 h of treatment, respectively. The EFB hydrolysate showed the eligibility for ethanol production without any supplements where ethanol yield was 0.275 g ethanol/g EFB in the presence of the IL, while lower yield obtained without IL-pretreatment. Moreover, it was demonstrated that furfural and phenolic compounds were not at the level of suppressing the fermentation process

Prediction of retention time of cutinases tagged with hydrophobic peptides in hydrophobic interaction chromatography

Hydrophobic interaction chromatography (HIC) is an important technique for protein purification, which exploits the separation of proteins based on hydrophobic interactions between the stationary phase ligands and hydrophobic regions on the protein surface. One way of enhancing the purification efficiency by HIC is the addition of short sequences of peptide tags to the target protein by genetic engineering, which could reduce the need for extra and expensive chromatographic steps. In the present work, a methodology for predicting retention times of cutinases tagged with hydrophobic peptides in HIC is presented. Cutinase from Fusarium solani pisi fused to tryptophan–proline (WP) tags, namely (WP)2 and (WP)4, and produced in Saccharomyces cerevisiae strains, were used as model proteins. From the simulations, the methodology based on tagged hydrophobic definition proposed by Simeonidis et al. (Φtagged), associated to a quadratic model for predicting dimensionless retention times, showed small differences (RMSE < 0.022) between observed and estimated retention times. The difference between observed and calculated retention times being lower than 2.0% (RMSE < 0.022) for the two tagged cutinases at three different stationary phases, except for the case of cut_(wp)2 in octyl sepharose–2 M ammonium sulphate. Therefore, we consider that the proposed strategy, based on tagged surface hydrophobicity, allows prediction of acceptable retention times of cutinases tagged with hydrophobic peptides in HIC.info:eu-repo/semantics/publishedVersio

Use of ionic liquids in the pretreatment of forest and agricultural residues for the production of bioethanol

Pretreatment of lignocellulosic materials is an important step to achieve higher amounts of simple sugars, mono- and disaccharides, for obtaining ethanol as a biofuel, via enzymatic hydrolysis. The study introduces a concept that utilizes ionic liquids (ILs) as solvents in the pretreatment step, before enzymatic saccharification, for both forest residues (Eucalyptus (Eucalyptus globulus Labill.) and Lenga (Nothofagus pumilio (POEPP. EX. ENDL.) KRASSER) and for agricultural residues (wheat and corn). The procedure was evaluated at four different temperatures (SO, 121, 150 and 170 degrees C) for 30 and 60 min, respectively, with 1-ethyl-3-methylimidazolium chloride ([EMIM(+)][Cl(-)]). Subsequent enzymatic hydrolysis of these materials was carried out at 47 degrees C, for 72 h, with commercial cellulases. The results demonstrated that the best experimental conditions found for wheat, corn and Eucalyptus residues were the following: 150 C, for 60 min, yielding a total of 46, 48 and 30% sugars, respectively; in the case of Lenga residues, the optimum conditions were: 150 degrees C for 30 min, yielding a total of 40% sugars after saccharification. Finally, an analysis of the solid material after ionic liquid pretreatment is required, to determine the changes related to lignin, cellulose and hemicellulose composition