engleski

Development of alcohol dehydrogenase catalyzed hexanal production process in different types of microreactors

Every year, in pharmaceutical and fine chemical industry demand for new technologies and new products is increasing. High purity of products, mild operation conditions and development of products that could be labelled “natural” is of highest interest due to market demands. The “green note” molecules are part of them. They are high value molecules, mostly six-carbon alcohols and aldehydes such as hexanal, used in aroma industry1. Their market is estimated at USD 20 – 40 million per year2. Microreactor technology, a new approach in the chemical engineering, offers potential benefits when compared to macroreactor processes applied in present industries. High interfacial area, well-defined flow patterns, better process control, reduction of total energy consumption is what makes them an interesting option for enhancing the process performance3. In this work, effect of initial enzyme and coenzyme concentration and type of microreactor on hexanol oxidation catalyzed by commercial alcohol dehydrogenase was investigated. Three different continuously operated tubular microreactors with two “Y”-shaped inlets and one outlet were used to compare effect of residence time, microchanal geometry and mixing on conversion and productivity. Introducing two immiscible phases (organic phase were hexanol was dissolved in hexane and water phase were enzyme and coenzyme (NAD+) were dissolved in water) slug (plug) flow was formed. Changes on flow (slug dimensions) pattern when total fluid flow was altered were also observed and investigated. Conversion of 9.91 % achieved in microreactor equipped with micromixers at residence time of 1.6 s was significant improvement in comparison with results obtained in conventional batch reactor where half of this conversion was achieved after 180 s 4. Due to mixing effect smaller slugs were developed in this type of microreactor in comparison to tubular reactors for the same flow rate indicating a great effect of mixing on mass transfer

microreactor; multiphase flow; hexanol oxidation; alcohol dehydrogenase

Ovaj se tekst temelji na radu koji je financirala Nacionalna zaklada za znanost, visoko školstvo i tehnologijski razvoj Republike Hrvatske.