Uniform cross-linked cellulase aggregates prepared in millifluidic reactors

•Millifluidic reactor can be used to prepare cross-linked cellulase aggregate (XCA).•The XCA has a very uniform size distribution between 200 nm and 400 nm.•Flow rates and mixing patterns can be precisely controlled.•It is possible to control the particle size of the XCA.•It shows excellent thermal stability, and can be reused for several cycles.

HypothesisUniform cross-linked cellulase aggregate (XCA) can be prepared by using a millifluidic reactor which consists of two inlets and a Y-junction, because mixing pattern and spatial distribution of reactants can be controlled precisely.ExperimentsAqueous cellulase solution is mixed with acetonitrile (as a precipitant) and 20 mM of glutaraldehyde (as a cross-linker) at the Y-junction. XCA is collected from the outlet of the reactor.FindingsUniform XCA, with an average size between 200 nm and 400 nm, can be formed inside the reactor. Unlike free cellulase, XCA is insoluble such that it can be filtered out from the solution. It can be used alone or absorb on silica gel (XCA-Si) as a catalyst for hydrolyzing carboxymethyl cellulose (CMC). Interestingly, XCA-Si shows highest activity at pH 4.8 and 50 °C, which is similar to the optimal condition of free cellulase. Moreover, XCA-Si is more stable than free cellulase at high temperature (>60 °C). It precipitates naturally and can be recycled at least 5 times after the hydrolysis of CMC.

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