The effect of room temperature ionic liquids on the selective biocatalytic hydrolysis of chitin via sequential or simultaneous strategies

Abstract

N-Acetylglucosamine and N,N′-diacetylchitobiose are efficiently and selectively produced from chitin biomass by using RTILs and chitinases.

Mechanoenzymatic Breakdown of Chitinous Material to N‐Acetylglucosamine: The Benefits of a Solventless Environment

“…This methodology enables the direct conversion of at least 40 % of its chitin content into the GlcNAc monomer. The benefits of RAging are further highlighted by comparing the substrate loading used and the concentration of obtained GlcNAc with those of previously reported methods (Table S1 in the Supporting Information) . The typical substrate loading for RAging was at least one order of magnitude larger than for methods in which bulk solvent is used, and even considering studies on less recalcitrant and/or pretreated chitin forms than the one used here, our GlcNAc yield [mg mL −1 ] was approximately 2–30 times superior.…”

“…This is strikingly different from the conditions under which microbe-secreted enzymes,s uch as chitinases, have evolved to thrive in. We showedt hat both the efficiency and selectivity of chitinase are increased several times by switching from solution-based environments, traditionally used in enzymatic reactions, [9,[14][15][16][17][18][19][20][21][22][23][24][25][26] to RAging conditions that operateo nm oist solid substrates in the absence of bulk solvent media. Our current hypothesis is that aging is the closestt ot he natural environment of microbial chitinases (under which there is no need for an exceedingly highreaction rate), whereas RAging, withi ts periodic milling activation events,m ay further accelerate the reaction through mechanical effects and improved mixing.…”

“…Although chitinases,t hat is, enzymes that catalyzet he hydrolysiso fc hitin into itsm onomer,o ffer an opportunity for clean processing of chitin (Scheme 1), their use is hindered by the poor solubilityo fc hitin, which requires harsh pretreatment of the chitinous material, [9,[14][15][16][17][18][19][20][21][22][23][24][25][26] for example, with HCl to form a colloidalc hitin suspension, [27] or by using phosphoric acid to generate swollenc hitin. [28] Further,t here is an eed to improve chitinase activity and stabilityf or biotechnological applications.…”

Use of Ionic Liquids in Chitin Biorefinery: A Systematic Review

“…Although enzymatic reactions (hydrolysis and deacetylation) could proceed without use of IL (IL is considered to be non-essential activator), ILs disrupt the H-bonding and thus facilitate the access of the enzyme to the substrate. This results in formation of different products and different product distribution profile (ratio of monomer to dimer to oligomers) than what is observed without the use of ILs (Husson et al, 2017;Berton et al, 2018). The IL systems also appear to be superior in terms of product yields and reaction speed.…”

“…The initial report used the IL 1-ethyl-3-methyl-imidazolium acetate ([C 2 mim][OAc]) to pre-treat chitin prior to enzymatic hydrolysis (Table 1, Entry 1). After pre-treatment, chitin was further hydrolyzed into the GlcNAc monomer using commercially available enzymes from Trichoderma viride and S. griseus (Husson et al, 2017). The IL-pre-treated (swollen) commercially available chitin resulted in a significant facilitation of, otherwise slow, enzymatic hydrolysis.…”