Studies in the Area of Applied microbiology and biotechnology Reported from University of Hamburg (Ionic liquid and deep eutectic solvent-activated CelA2 variants generated by directed evolution)
By a News Reporter-Staff News Editor at Biotech Week -- Fresh data on Biotechnology are presented in a new report. According to news reporting from Hamburg, Germany, by NewsRx journalists, research stated, "Chemoenzymatic cellulose degradation is one of the key steps for the production of biomass-based fuels under mild conditions. An effective cellulose degradation process requires diverse physico-chemical dissolution of the biomass prior to enzymatic degradation."
The news correspondents obtained a quote from the research from the University of Hamburg, "In recent years, 'green' solvents, such as ionic liquids and, more recently, deep eutectic liquids, have been proposed as suitable alternatives for biomass dissolution by homogenous catalysis. In this manuscript, a directed evolution campaign of an ionic liquid tolerant beta-1,4-endoglucanase (CelA2) was performed in order to increase its performance in the presence of choline chloride/glycerol (ChCl:Gly) or 1-butyl-3-methylimidazolium chloride ([BMIM]Cl), as a first step to identify residues which govern ionic strength resistance and obtaining insights for employing cellulases on the long run in homogenous catalysis of lignocellulose degradation. After mutant library screening, variant M4 (His288Phe, Ser300Arg) was identified, showing a dramatically reduced activity in potassium phosphate buffer and an increased activity in the presence of ChCl:Gly or [BMIM]Cl. Further characterization showed that the CelA2 variant M4 is activated in the presence of these solvents, representing a first report of an engineered enzyme with an ionic strength activity switch. Structural analysis revealed that Arg300 could be a key residue for the ionic strength activation through a salt bridge with the neighboring Asp287. Experimental and computational results suggest that the salt bridge Asp287-Arg300 generates a nearly inactive CelA2 variant and activity is regained when ChCl:Gly or [BMIM]Cl are supplemented (similar to 5-fold increase from 0.64 to 3.37 mu M 4-MU/h with the addition ChCl:Gly and similar to 23-fold increase from 3.84 to 89.21 mu M 4-pNP/h with the addition of [BMIM]Cl)."
According to the news reporters, the research concluded: "Molecular dynamic simulations further suggest that the salt bridge between Asp287 and Arg300 in variant M4 (His288Phe, Ser300Arg) modulates the observed salt activation."
For more information on this research see: Ionic liquid and deep eutectic solvent-activated CelA2 variants generated by directed evolution. Applied Microbiology and Biotechnology, 2014;98(12):5775-5785. Applied Microbiology and Biotechnology can be contacted at: Springer, 233 Spring St, New York, NY 10013, USA. (Springer - www.springer.com; Applied Microbiology and Biotechnology - www.springerlink.com/content/0175-7598/)
Our news journalists report that additional information may be obtained by contacting C. Lehmann, University of Hamburg, Biozentrum Klein Flottbek, Abt Mikrobiol & Biotechnol, D-22609 Hamburg, Germany. Additional authors for this research include M. Bocola, W.R. Streit, R. Martinez and U. Schwaneberg (see also Biotechnology).
Keywords for this news article include: Biotechnology, Europe, Hamburg, Germany
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