Refine
Document Type
- Part of a Book (4)
- Article (3)
- Conference Proceeding (1)
Language
- English (8)
Has Fulltext
- yes (8)
Keywords
- Lipase (3)
- CALB (2)
- Esterification (2)
- Acceptor reaction (1)
- Alternansucrase (1)
- Amino Acids (1)
- Aminosäuren (1)
- Antimicrobial Activity (1)
- Bio-Based Surfactants (1)
- Bio-based (1)
Faculty
Linoleic acid hydroperoxides are versatile intermediates for the production of green note aroma compounds and bifunctional ω-oxo-acids. An enzyme cascade consisting of lipoxygenase, lipase and catalase was developed for one-pot synthesis of 13-hydroperoxyoctadecadienoic acid starting from safflower oil. Reaction conditions were optimized for hydroperoxidation using lipoxygenase 1 from Glycine max (LOX-1) in a solvent-free system. The addition of green surfactant Triton CG-110 improved the reaction more than two-fold and yields of >50% were obtained at linoleic acid concentrations up to 100 mM. To combine hydroperoxidation and oil hydrolysis, 12 lipases were screened for safflower oil hydrolysis under the reaction conditions optimized for LOX-1. Lipases from Candida rugosa and Pseudomonas fluorescens were able to hydrolyze safflower oil to >75% within 5 h at a pH of 8.0. In contrast to C. rugosa lipase, the enzyme from P. fluorescens did not exhibit a lag phase. Combination of P. fluorescens lipase and LOX-1 worked well upon LOX-1 dosage and a synergistic effect was observed leading to >80% of hydroperoxides. Catalase from Micrococcus lysodeikticus was used for in-situ oxygen production with continuous H2O2 dosage in the LOX-1/lipase reaction system. Foam generation was significantly reduced in the 3-enzyme cascade in comparison to the aerated reaction system. Safflower oil concentration was increased up to 300 mM linoleic acid equivalent and 13-hydroperoxides could be produced in a yield of 70 g/L and a regioselectivity of 90% within 7 h.
Starmerella bombicola is known to produce sub‐terminally hydroxylated lactonic sophorolipids (SLs), while Candida kuoi synthesizes acidic open chain SLs with terminally hydroxylated fatty acids. Upon feeding glucose and fatty alcohols both strains form long‐chain nonionic SLs. According to structure elucidation the SLs consist of a hydroxylated fatty acid esterified with fatty alcohol and linked via a glycoside bond to the diacetylated sophorose unit. Palmityl, stearyl, and oleyl alcohols lead to products with lipid chain lengths of C32 or C36. Oleyl alcohol is the preferred substrate leading to 45 g L−1 of the double unsaturated C36 SL with S. bombicola and 20 g L−1 with C. kuoi. Scale up from shake flask to 1.5 L fermentations is possible and 65 g L−1 long‐chain SLs are obtained with S. bombicola within 7 days. Mixed feeding of oleic acid and a variety of fatty alcohols leads to new long‐chain SLs. In the presence of oleic acid the yeasts do not oxidize the fatty alcohol and thus the production of biosurfactants with tailored chain length is possible. The long‐chain SLs show good emulsification ability of water/paraffin oil mixtures at low energy input and reduced interfacial tension significantly.
Practical Applications: Sophorolipids are produced by fermentation on industrial scale focusing on cleaning and detergent applications. Mainly lactonic or anionic open‐chain forms are used today. The new long‐chain SLs presented in this manuscript are accessible with existing production technology and can be produced with high titers from cost‐efficient renewable raw materials. In contrast to the commercial products the long‐chain SLs are more hydrophobic and exhibit a strong emulsification behavior. Therefore they have the potential to broaden the application range of SLs in future. They may be useful as novel emulsifiers for cosmetic creams and lotions, pharmaceutical ointments and food products or may find application in oil spill remediation.
Due to the worldwide shortage of petrochemical based resources, the usage of renewable bio-based raw materials for established and novel products becomes increasingly important.[1] Such bio-based resources are already used for the fabrication of a variety of products, e. g. paper, lubricants, detergents or cosmetics. In the future they are expected to emerge in many more applications in industry and household.[1]
A very promising approach relies on the use of glycolipids as a source of hydroxy-oleic acid.[2] Microbial glycolipids are produced for instance via fermentation from natural resources such as plant oils and sugar.[3] After fermentation complex product mixtures are obtained with the composition depending on the microorganism, substrate and fermentation time.[3] The successful use of microbial glycolipids and hydroxy-oleic acid (HOA) derived therefrom as bio-based intermediates requires reliable analytical methods as well as robust manufacturing processes for the synthesis and cleavage of bio-based molecules. In order to obtain hydroxy-oleic acids as bio-based intermediates, the acidic cleavage of microbial derived sophorolipid was investigated. In addition the implementation of HOA in polyurethane (PU) systems was explored.
Comparative analysis of non-natural acceptor glucosylation with sucrase enzymes of family GH 70
(2019)
Mutan- and alternansucrase were analyzed for their non-natural glucosylation potential with catecholic compounds caffeic acid and nordihydroguaiaretic acid (NDGA) as well as with non-catecolic p-coumaric acid and umbellic acid. Mutansucrase accepted both catecholic substrates and high glucosylation yields of 92 % with caffeic acid and 81 % with NDGA were obtained. The enzyme showed a clear regio-preference for the catechol 4-OH, which corresponds to findings from our previous work with Leuconostoc and Weissella derived glucansucrases. The substrate spectrum of the alternansucrase was broader and all substrates were successfully glucosylated with a preference for the catechols. Interestingly alternansucrase possessed a different regio-specificity. With caffeic acid the 3-O-α-D-glucoside was the major product. A similar substrate spectrum and regioselectivity pattern was observed in previous glucansucrase screenings only with glucansucrase from strain Weissella beninensis DSM 22752. Therefore it may be concluded that the W. beninensis enzyme is an alternansucrase type enzyme as well.
Pseudozyma antarctica Lipase B catalyzed esterification and transesterification in deep eutectic solvents (DES) was investigated in reaction systems with alcohols of different polarity. Coconut oil and crude biodiesel were deacidified successfully with non-immobilized CALBL and final acid values of 1.2 for biodiesel and 0.5 for coconut oil were obtained, while no esterification with ethanol was observed without DES. Water depletion of the lipid phase in the presence of water adsorbing DES causes this difference. Analysis of water contents revealed a 10 fold lower water content of the lipid phase in the presence of a second DES phase than in trials without utilization of DES. In contrast reactions of hydrophilic polyols are suppressed in the presence of DES. While the esterification of fructose and the transesterification with glycerol worked well in the polar solvent 2-methyl-2-butanol, almost no fructose esterification and a decreased transesterification with glycerol were observed in the presence of DES. Analysis of logP values of the substrates explains the substrate dependent differences in reactivity. The polar alcohols are probably bound strongly in the hydrogen-bonding network of the DES phase and are thus not available for lipase catalyzed reactions.
The synthesis of 17-hydroxy-oleic acid based oligomeric esters was investigated with immobilized Pseudozyma antarctica Lipase B and hexanediol as co-substrate. The effects of different reaction parameters on velocity and product composition at equilibrium conditions were analyzed. The synthesis of oleic acid esters was used as a reference system for initial evaluation of reaction parameters. The reaction with oleic acid and hexanediol was fastest at an enzyme concentration of 5% at 60 °C and high conversions of > 90 % were achieved in non-polar solvents in the presence of molecular sieves. In heptane an oleic acid conversion of 96 % was reached with a final diester to monoester ratio of > 4:1. In syntheses trials with 17-hydroxy-oleic acid the formation of oligomers was verified with GPC, however; conversion was generally lower than with oleic acid. Removal of hydroxyl fatty acid monomers and dimers and the formation ester functionalities could be verified by GC analysis. An increase of the degree of oligomerization was observed simultaneously by GPC analysis. The number-average molecular weight was around 1400 in the best trials corresponding to a degree of oligomerization of around 4 units of hydroxyl-fatty acid attached to a hexanediol core. Though transformations were not complete, the final oligomer size was in the lower range of polyester diols used for polyurethane manufacturing.
STEPsCON 2018 was jointly organized by the Faculty of Applied Natural Sciences of TH Köln (Germany) and the University of Oulu (Finland) on the occasion of the 50th anniversary of the Leverkusen – Oulu town twinning. The conference focused on sustainability issues and covered the current state of research in four key topics:
1. Sustainable Medicine and Pharmaceuticals
2. Resources and Bioremediation
3. Sustainable Chemistry & Industrial Biotechnology
4. Innovative Materials & Formulations
Current changes in environmental legislation and customer demands set an urge for the development of more sustainable surfactants. Thus, the objective of this work was the development of novel environmentally friendly amino acid surfactants. Combining Diels–Alder cyclization of myrcene with maleic or citraconic anhydride followed by ring opening with amino acids enabled a synthesis route with a principal 100% atom economy. Variation of amino acids resulted in a large structural variety of anionic and amphoteric surfactants. Lysine gave access to either a mono-acylated product bearing a cationic side chain or a bi-acylated gemini surfactant. First, anhydride precursors were synthesized in yields of >90% in a Diels–Alder reaction under microwave radiation and subsequent amino acid coupling in aqueous environment gave fully bio-based surfactants in good yields and purity. Physicochemical characterization showed an enhanced decrease in surface tension upon addition of amino acids to the myrcene–anhydride backbone, resulting in a minimal value of 31 mN·m−1 for gemini–lysine. Foamabilitiy and foam stability were significantly increased at skin-friendly pH 5.5 by incorporation of amino acids. The carboxylic groups of surfactants with arginine were esterified with ethanol to access cationic compounds. Comparative analysis revealed moderate antimicrobial effects against yeast, Gram-positive bacteria, and Gram-negative bacteria.