Peptic digestion of bovine hemoglobin yields a fragment with antibacterial activity. This peptide was purified to homogeneity by a two-step procedure including anion exchange chromatography and preparative reversed-phase HPLC. Mass determination and fragmentation indicated that this peptide corresponded to the 1^23 fragment of the K K chain of hemoglobin. The minimum inhibitory concentration and mode of action of this peptide towards Micrococcus luteus strain A270 were determined. Hemolytic assay, interaction with liposomes, and study of its structure in solution were also performed. ß

Here an overview of all pathways that integrate chemical and biological catalysis is presented. We emphasize the factors to be considered in order to understand catalytic synergy.

The kinetics of the alpha (1-23) peptide, which is the first anti-bacterial peptide to be isolated from a haemoglobin hydrolysate, was studied in the course of peptic hydrolysis at pH 4.5 and 23 degrees C in an homogeneous-phase system. A one-step reversed-phase HPLC coupled with photodiode array detector method was applied to identify and isolate this anti-bacterial peptide. The kinetics of peptide appearance were investigated in acetate buffer alone and in urea as a haemoglobin-denaturing agent. Two different mechanisms, 'one-by-one' for native haemoglobin hydrolysis and 'zipper' for denatured haemoglobin hydrolysis, were observed. Whatever the haemoglobin state, native or denatured, and whatever the hydrolytic mechanism, one-by-one or zipper, the anti-bacterial alpha (1-23) peptide is a transient peptide. To prepare the alpha (1-23) peptide it is suitable to hydrolyse haemoglobin in the presence of urea at a corrected degree of hydrolysis (DH(c)) of 13.5%. The amount of peptide produced in the presence of urea was twice as high as for the hydrolysis of native haemoglobin. The yields of alpha (1-23) peptide with respect to haemoglobin at the optimal DH(c) values were 55 and 25% respectively.

Innovations in novel enzyme discoveries impact upon a wide range of industries for which biocatalysis and biotransformations represent a great challenge, i.e., food industry, polymers and chemical industry. Key tools and technologies, such as bioinformatics tools to guide mutant library design, molecular biology tools to create mutants library, microfluidics/microplates, parallel miniscale bioreactors and mass spectrometry technologies to create high-throughput screening methods and experimental design tools for screening and optimization, allow to evolve the discovery, development and implementation of enzymes and whole cells in (bio)processes. These technological innovations are also accompanied by the development and implementation of clean and sustainable integrated processes to meet the growing needs of chemical, pharmaceutical, environmental and biorefinery industries. This review gives an overview of the benefits of high-throughput screening approach from the discovery and engineering of biocatalysts to cell culture for optimizing their production in integrated processes and their extraction/purification.

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Lignin is the second most abundant polymer after cellulose in lignocellulosic biomass. Its aromatic composition and recalcitrant nature make its valorization a major challenge for obtaining low molecular weight aromatics compounds with high value-added from the enzymatic depolymerization of industrial lignins. The oxidation reaction of lignin polymer using laccases alone remains inefficient. Therefore, researches are focused on the use of a laccase-mediator system (LMS) to facilitate enzymatic depolymerization. Until today, the LMS system was studied using water-soluble lignin only (commercial lignins, modified lignins, or lignin model compounds). This work reports a study of three LMS systems to depolymerize the three major industrial lignins (organosolv lignin, Kraft lignin, and sodium lignosulfonate). We show that an enzymatic depolymerization of these lignins can be achieved by LMS using laccase from Trametes versicolor, 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt as mediator and a cosolvent (25% of 1,4-dioxane) to enhance the solubilization of lignins. C 2020

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IntroductionInterest in the conversion of biomass into chemicals, fuels, and energy has been increasing sharply during the last decades. The expected depletion of oil and the urgentn eed to decrease greenhouse gas emissions combined with the growing interest of consumersf or more sustainable goods are driving efforts to develop alternative pathways through the valorization of renewable carbon sources. [1] Catalysis is ak ey parameter for the efficient and environmentally friendly transformationo fb iomass, especially for lignocellulosicb iomass,a na bundant but recalcitrant substrate. [2,3] Consequently,e ach area of catalysis must be mobilized to handlet his tremendous challenge of the 21st century. For instance,b iocatalysis processes are already or are about to be industrialized for the enzymatic saccharification of cellulose to glucose andf or the fermentation of glucose to succinic acid [4] in as electivea nd economically viable manner under smooth conditions. Heterogeneous and homogeneousc hemocatalysts, alone or in combination, [5] also show high productivity for the transformation of biomass,b ut the selectivity to specific chemical targets is often difficultt oa chieve fully. [6] Each catalysis type could complemente ach other by taking advantage of the chemo-,r egio-, and stereoselectivity of biocatalysis and the productivity and the large substrate scopeo fc hemocatalysis. Such ao ne-pot synergetic combination encompasses the novel "hybrid catalysis" concept. [7] Al ot of examples of biocatalysis and chemocatalysis conductedi nm ultistep one-pot chemoenzymatics yntheses were recently reviewed. [8] Compatibility issues owing to differences in optimal pH, temperature, atmosphere,a nd substrate and catalysti nteractions often do not allow both types of catalysis to work in tandem. Such incompatibilities have motivated researchg roups to imagine innovative technological solutions to avoid mutuald eactivation,a nd these include the use of membranes, [9] catalyst encapsulation, [10] immobilization, [11] and/orb iphasic reactors. [12] An important requirement to achieve an efficient and "real" one-pot hybrid system is to find suitable conditions and catalysts to enable reactions to proceed simultaneously while keeping sufficient efficiency and selectivity.P rogress in both bioengineering, to create more robuste nzymes, and in chemistry, to optimize activity and selectivity in the aqueous phase, has undoubtedly openedahuge new field in catalysis for the next decades.In the field of biosourced chemistry,t he conversion of glucose into 5-hydroxymethylfurfural (5-HMF) is am ajor challenge that is currently being addressed by many research groups Through biomass valorization, sugars can become am ajor carbon resource for the production of fuels and chemicals by using catalysis. Hybridc atalysis, ad irect combination of biocatalysis and chemocatalysis, may yield innovative solutions. 5-Hydroxymethylfurfural( 5-HMF) is ap latform molecule derived from glucose, for which fructose is ak ey intermediate. To overcome t...