Mechanochemistry enables enzymatic cleavage of cellulose into glucose without bulk solvents, acids, other aggressive reagents, or substrate pre-treatment. This clean mechanoenzymatic process (coined RAging) is also directly applicable to biomass, avoids many limitations associated with the use of cellulases, and produces glucose concentrations greater than three times that obtained by conventional methods.

Chitin is not only the most abundant nitrogen‐containing biopolymer on the planet, but also a renewable feedstock that is often treated as a waste. Current chemical methods to break down chitin typically employ harsh conditions, large volumes of solvent, and generate a mixture of products. Although enzymatic methods have been reported, they require a harsh chemical pretreatment of the chitinous substrate and rely on dilute solution conditions that are remote from the natural environment of microbial chitinase enzymes, which typically consists of surfaces exposed to air and moisture. We report an innovative and efficient mechanoenzymatic method to hydrolyze chitin to the N‐acetylglucosamine monomer by using chitinases under the recently developed reactive aging (RAging) methodology, based on repeating cycles of brief ball‐milling followed by aging, in the absence of bulk solvent. Our results demonstrate that the activity of chitinases increases several times by switching from traditional solution‐based conditions of enzymatic catalysis to solventless RAging, which operates on moist solid substrates. Importantly, RAging is also highly efficient for the production of N‐acetylglucosamine directly from shrimp and crab shell biomass without any other processing except for a gentle wash with aqueous acetic acid.

The activity of b-glucosidases-the enzymes responsible for the final step in the enzymatic conversion of cellulose to glucose-can be maintained and manipulatedu nder mechanochemicalc onditions in the absence of bulk solvent, either through an unexpected stabilization effect of inert surfaces, or by alteringt he enzymatice quilibrium. The reported results illustrateu nique aspects of mechanoenzymatic reactions that are not observable in conventionala queous solutions. They also represent the first reported strategies to enhance activity and favor either direction of the reactionu nder mechanochemicalconditions.Celluloseist he most abundant biopolymer on Earth [1] and central to many strategies for developing renewable and sustainable alternatives to fossil resources for the production of fuels and chemicals. [2] The deployment of lignocellulosic biomass as ar enewable feedstocki sh indered by its recalcitrantn ature,i ncluding its poor solubility and low reactivity. [3] Additionally,c ellulose in lignocellulosic material is intricately mixed with the biopolymers hemicellulose andl ignin, [4] impeding its accessibility and separation, and requiring the use of harsh and wasteful conditions for biomass saccharification. [5] Whereas cellulosic materials in nature are degraded by mixtures of cellulase enzymes (exoglucanases, endoglucanases, b-glucosidases, etc.) secreted by microorganisms, the use of such enzymes in cellulose-based industries requires initial harsh physical and chemical pretreatment of the cellulosicm aterial, fore xample, with sulfuric acid. [6] Furthermore, since b-glucosidases (BGs)-enzymes responsible for cleavage of the b-(1-4)-glucosed imer (cellobiose)i nto glucose( Scheme 1)-are often limiting in cellulase mixtures, incomplete depolymerization is ac ommon problem. [7] Recently,w er eported that cellulases can catalyze the efficient hydrolysis of both microcrystalline cellulose (MCC) and raw lignocellulosic biomassd irectly into glucose without chemicalp retreatment. [8] This was made possible by am echanochemistry-based process termedr eactive aging (RAging), which consists of alternating cycles of brief mechanochemical activation by milling in the presence of am inute amount of water,f ollowed by aging [9] of the resulting moist powder at a mild temperature (45-55 8C). The volume of water used in RAging is significantly lower than in conventionals olutions or slurries, with the liquid-to-solidr atio (h) [10] below 1 mLmg À1 , consistentw ith liquid-assisted grinding (LAG) mechanochemical conditions. [11] By using near-stoichiometric amounts of water,t his solvent-free environment better mimics the conditions for whichc ellulases have been naturally selected for,a chieving af ast, efficient, and clean hydrolysis of crystalline cellulose or native biomass.F urthermore, RAging avoids the energy consumption associated with continuous heatinga nd stirring of large volumes of aqueous suspensions used in conventional processes and affords the highest glucose concentration reportedt od ate for...

In order to avoid side effects at the time of cancer eradication to the patients, the selectivity of treatments has become of strategic importance. In the case of photodynamic therapy (PDT), two-photon absorption combined with active targeting of tumors could allow both spatial and chemical selectivity. In this context, we present the synthesis, spectroscopic, and biological properties of a series of porphyrin-triphenylamine hybrids with excellent singlet oxygen production capacities and good two-photon absorption.