Ole Kirk's research while affiliated with Novozymes and other places

... THE RECENT INTRODUCTION of selected esters of monosaccharides in biomedical research has allowed an increase in the nutritional value or metabolic efficiency of several hexoses and their antimetabolic analogs (10). For instance, ␣-D-glucose pentaacetate augments glycolytic flux and insulin release in rat pancreatic islets to a larger extent than unesterified D-glucose tested at the same concentration as its ester (21,27). Likewise, D-mannoheptulose hexaacetate inhibits D-glucose phosphorylation in different cell types otherwise resistant to the unesterified heptose (4,17). ...

... These two groups carry hydrophilic and lipophillic balance, which then helps indicate whether the surfactant is emulsified, wetting, solvent, detergent or anti-foam, and so on (Nesterenko, et al, 2014;Mattei, et al, 2014). Kirk (1998) has carried out an asetalization reaction of glucose and chloropropane, in which asetalization occurs in the position of C1 hydroxyl groups hemiacetal with the group of hydroxyls of propanol. Surfactant of tert-butyl galactocidase through an asetalization reaction of galactose and tert-butanol has been synthesized using p-TSA catalyst and the result indicates a CMC of 0.02 % and hydrophilic-lipophilic balance (HLB) of 3.93 (Sembiring, 2007). ...

... The realisation that enzymes can function in non-aqueous media has given to their synthetic potential a powerful boost for many processes (Ikeda and Klibanov, 1993; Klibanov, 1989; Patel et al., 1996; Zaks and Klibanov, 1985). Amongst the numerous enzymes studied in such systems, esterases and in particular lipases have been successfully utilized in a wide range of stereoselective and regioselective acylations of various target molecules including sugars (Kirk et al., 1995; Ljunger et al., 1994; Patel et al., 1996; Tsitsimpikou et al., 1998 ). The first attempt of the enzymatic esterification of cellulose was made a few years ago (Sereti et al., 1998Sereti et al., , 2001) by subjecting Avicel cellulose, the fatty acid as substrate and lipase into several organic solvents. ...

... A P. aeruginosa cold active lipase variant (Lip C D2H8) obtained by saturation muta- genesis could retain activity till 50 °C beyond which it declined ( Cesarini et al., 2012). It has also been reported that through site di- rected mutagenesis thermostabilty could be increased, though with limitations for Lipase-B from Candida antartica (60 °C, activity lost in 25 min) and TAB-5 Antarctic strain (50 °C, activity lost in 60 min) ( Patkar et al., 1997;Tsigos et al., 2001). According to our findings NP- lipase retained activity for over 3 h at 55 °C. ...

... I also did some work trying to design a catalytic enzyme meant to bleach color in solution during washing, thus preventing transfer to lighter colored clothes. 23 I write about this experience because it was also my first learning of (unfair) competition in science, as we were never named inventors on the patent application for the 43kD cellulase. I did not know much of such things back then, just very eager to do something useful, and I moved to Diabetes Research at Novo Nordisk in 1991, where I became the youngest in the group looking to identify new treatments for type 2 diabetes. ...

... One subgroup of peroxy compounds are peroxy acids, which, apart from their relevance for atmospheric chemistry, are widely used as chemical reagents, disinfectants and bleaching agents (Holah et al., 1990;Luukkonen and Pehkonen, 2017;Milne, 1998;Ramirez, 2008;Reinhardt and Borchers, 2009). Due to their widespread practical applications, several methods have been developed both for the quantification of the overall peracid content (Davies and Deary, 1988;Greenspan and MacKellar, 1948) and for the separation and detection of specific peracids (Cairns et al., 1975;Effkemann et al., 1998;Kirk et al., 1992). These methods use relatively unspecific detectors such as flame ionisation, electrochemical and UV-VIS detectors. ...

... The most common is the preliminary alkylation of the hydrophilic compound resulting in the formation of an ether bond. The methyl, ethyl n-propyl or butyl alkyl derivatives of sugars proved to be interesting for subsequent enzymatic lipophilization reactions even though this strategy requires an additional deprotection step at the end of the process ( Björkling et al., 1989;Bisht et al., 1999;Bousquet et al., 1999). Protecting groups such as isopropylidene, benzylidene or cyclohexylidene are also widely used fro hydrophobization and improvement of the solubility of the substrate in the given solvent. ...

... Candida antarctica is a psychrophilic Basidiomycetous yeast originally selected from a strain found in Antarctic habitats. This strain expresses two lipolytic enzymes displaying different catalytic properties: Candida antarctica lipase A (CALA) and lipase B (CALB) [1]. CALB, first described in 1994 [2], has a molecular weight of approximately 34-43 kDa. ...

... The main disadvantages in the use of biocatalytic systems are the cost of enzymes and the separation from the final products in the bioreaction medium, slow reaction rates, and the absence of optimized reactors for biphasic media catalysis [50]. ...

... Accordingly, early immunoassays, radioimmunoassays and sandwich enzyme-linked immunosorbent assays (ELISA), displayed significant discrepancies in measurements caused by differences in cross-reactivity of the antibodies. 29,30 Collectively, well-characterised antibodies with high specificity and affinity are crucial for reliable measurements of specific types or groups of GLP-1 metabolites. ...