Compatible ionic liquid-cellulases system for hydrolysis of lignocellulosic biomass

Ionic liquids (ILs) have been increasingly recognized as novel solvents for dissolution and pretreatment of cellulose. However, cellulases are inactivated in the presence of ILs, even when present at low concentrations. To more fully exploit the benefits of ILs it is critical to develop a compatible IL‐cellulases system in which the IL is able to effectively solubilize and activate the lignocellulosic biomass, and the cellulases possess high stability and activity. In this study, we investigated the stability and activity of a commercially available cellulases mixture in the presence of different concentrations of 1‐ethyl‐3‐methylimidazolium acetate ([Emim][OAc]). A mixture of cellulases and β‐glucosidase (Celluclast1.5L, from Trichoderma reesei, and Novozyme188, from Aspergillus niger, respectively) retained 77% and 65% of its original activity after being pre‐incubated in 15% and 20% (w/v) IL solutions, respectively, at 50°C for 3 h. The cellulases mixture also retained high activity in 15% [Emim][OAc] to hydrolyze Avicel, a model substrate for cellulose analysis, with conversion efficiency of approximately 91%. Notably, the presence of different amounts of yellow poplar lignin did not interfere significantly with the enzymatic hydrolysis of Avicel. Using this IL‐cellulase system (15% [Emim][OAc]), the saccharification of yellow poplar biomass was also significantly improved (33%) compared to the untreated control (3%) during the first hour of enzymatic hydrolysis. Together, these findings provide compelling evidence that [Emim][OAc] was compatible with the cellulase mixture, and this compatible IL‐cellulases system is promising for efficient activation and hydrolysis of native biomass to produce biofuels and co‐products from the individual biomass components. Bioeng. 2011; 108:1042–1048. © 2010 Wiley Periodicals, Inc.     

Application of immunohistochemical staining to detect antigen destruction as a measure of tissue damage

Electrocautery and directed energy devices (DEDs) such as lasers, which are used in surgery, result in tissue damage that cannot be readily detected by traditional histological methods, such as hematoxylin and eosin staining. Alternative staining methods, including 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) to stain live tissue, have been reported. Despite providing superior detection of damaged tissue relative to the hematoxylin and eosin (H&E) method, the MTT method possesses a number of drawbacks, most notably that it must be carried out on live tissue samples. Herein, we report the development of a novel staining method, "antigen destruction immunohistochemistry" (ADI), which can be carried out on paraffin-embedded tissue. The ADI method takes advantage of epitope loss to define the area of tissue damage and provides many of the benefits of live tissue MTT staining without the drawbacks inherent to that method. In addition, the authors provide data to support the use of antibodies directed at a number of gene products for use in animal tissue for which there are no species-specific antibodies commercially available, as well as an example of a species-specific direct antibody. Data are provided that support the use of this method in many tissue models, as well as evidence that ADI is comparable to the live tissue MTT method.     

Affinity chromatography in the industrial purification of plasma proteins for therapeutic use.

Affinity chromatography is a powerful technique for the purification of many proteins in human plasma. Applications cover the isolation of proteins for research purposes but also, to a large extent, for the production of therapeutic products. In industrial plasma fractionation, affinity chromatography has been found to be particularly advantageous for fine and rapid capture of plasma proteins from industrial plasma fractions pre-purified by ethanol fractionation or by ion-exchange chromatography. To date, affinity chromatography is being used in the production of various licensed therapeutic plasma products, such as the concentrates of Factor VIII, Factor IX, von Willebrand Factor, Protein C, Antithrombin III, and Factor XI. Most commonly used ligands are heparin, gelatin, murine antibodies, and, to a lesser extent, Cu(2+). Possible development of the use of affinity chromatography in industrial plasma fractionation should be associated to the current development of phage display and combinatorial chemistry. Both approaches may lead to the development of tailor-made synthetic ligands that would allow implementation of protein capture technology, providing improved productivity and yield for plasma products.     

Impact of Triton X-100 on alpha 2-antiplasmin (SERPINF2) activity in solvent/detergent-treated plasma

Large-pool solvent/detergent (SD) plasma for transfusion exhibits reduced alpha 2-antiplasmin (alpha2-AP; SERPINF2) functional activity. The reason for the loss of alpha2-AP has not been described and could be due to the SD incubation itself and/or to the processing steps implemented to remove the solvent and the detergent. We have studied alpha2-AP activity during six down-scale preparations of plasma virally-inactivated by 1% (v/v) TnBP combined with two different non-ionic detergents, either 1% Triton X-100 or 1% Triton X-45, at 31 degrees C for 4h. The SD-treated plasmas were then extracted with 7.5% (v/v) soybean oil, centrifuged at 3800 x g for 30 min, and subjected to hydrophobic interaction chromatography (HIC) to remove the SD agents. Control runs without TnBP and Triton were performed to evidence possible impacts of each process step on alpha2-AP activity. TnBP, Triton X-100, and Triton X-45 were measured at all stages of the processes to evaluate potential interferences with the alpha2-AP assay. Alpha 2-AP activity was about 10% that of starting plasma after 1% TnBP-1% Triton X-100 incubation and about 50% after oil extractions, centrifugation, and HIC. By contrast about 73% of the antiplasmin activity was found after the incubation with 1% TnBP and 1% Triton X-45, 88% after removal of the SD agents by oil extractions, 90% after centrifugation and 92% after HIC. The control runs performed without SD agents showed that the process steps did not affect the alpha2-AP activity. In conclusion, the agent altering alpha2-AP activity in SD-plasma is Triton X-100. The choice of detergents for the SD viral inactivation of therapeutic plasma fractions used in patients at risk of fibrinolysis should consider the impact on alpha2-AP activity.     

Degradation and mineralization of atrazine by a soil bacterial isolate.

An atrazine-degrading bacterial culture was isolated from an agricultural soil previously impacted by herbicide spills. The organism was capable of using atrazine under aerobic conditions as the sole source of C and N. Cyanuric acid could replace atrazine as the sole source of N, indicating that the organism was capable of ring cleavage. Ring cleavage was confirmed in 14CO2 evolution experiments with [U-14C-ring]atrazine. Between 40 and 50% of ring-14C was mineralized to 14CO2. [14C]biuret and [14C]urea were detected in spent culture media. Cellular assimilation of 14C was negligible, in keeping with the fully oxidized valence of the ring carbon. Chloride release was stoichiometric. The formation of ammonium during atrazine degradation was below the stoichiometric amount, suggesting a deficit due to cellular assimilation and metabolite-N accumulation. With excess glucose and with atrazine as the sole N source, free ammonium was not detected, suggesting assimilation into biomass. The organism degraded atrazine anaerobically in media which contained (i) atrazine only, (ii) atrazine and glucose, and (iii) atrazine, glucose, and nitrate. To date, this is the first report of a pure bacterial isolate with the ability to cleave the s-triazine ring structure of atrazine. It was also concluded that this bacterium was capable of dealkylation, dechlorination, and deamination in addition to ring cleavage.