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In recent years, water-in-oil Pickering emulsions have been introduced as promising reaction systems for multiphase enzyme catalysis, in particular lipase-catalyzed esterification and transesterification. Here, we for the first time gained insight into the effects that the presence of the proteins exert on the fineness and stability of the emulsion system and thus, the catalytic performance. We demonstrated a distinct, concentration-and enzyme-dependent decrease of droplet sizes in the dispersed phase, accompanied by decreasing stability against coalescence. This was due to a probably quantitative adsorption of lipases at the interphase intercalating the solid particles. Destabilization was reduced slightly at increased particle content and increased volume portion of the dispersed phase, respectively. However, the low tolerable lipase concentrations in the reaction system considerably limited its productivity. Thus, our study points at the enzyme content, or rather enzyme location, in Pickering emulsions being the crucial parameter for optimizing catalytic performance.

Enzyme haben sich in vielen Industriezweigen zu wichtigen Werkzeugen entwickelt und könnten in Zukunft besonders aufgrund der Transformation der chemischen Industrie hin zu klimaneutralen und nachhaltigen Prozessen an Bedeutung gewinnen. Für einen flächendeckenden Einsatz fehlt es jedoch an kosteneffizienten und effektiven Reinigungsmethoden, da vor allem das Downstream Processing einen bedeutenden Anteil an den Herstellungskosten haben kann. In den vergangenen Jahren wurden eine Vielzahl neuer Verfahren etabliert, um kostenintensive, chromatografische Schritte im Downstream Processing zu ersetzen. Eine vielversprechende, jedoch wenig beachtete Technik für die Enzymreinigung ist die Schaumfraktionierung. Diese Methode beruht auf der Bildung stabiler Schaumblasen, die durch die Adsorption oberflächenaktiver Moleküle an der Gas-Flüssigkeits-Grenzfläche von Luftblasen entstehen. Dadurch können Moleküle im Schaum angereichert und gereinigt werden. Die Schaumfraktionierung zeichnet sich durch milde Betriebsbedingungen, geringe Betriebskosten und einen einfachen apparativen Aufbau aus. Ihr Einsatz wird jedoch durch die Verwendung von Tensiden zur Schaumerzeugung und -stabilisierung sowie die potenzielle Denaturierung und Inaktivierung von Enzymen an der Gas-Flüssigkeits-Grenzfläche und die Unspezifität der Methode verhindert. Fusionsproteine, abgeleitet von natürlichen oberflächenaktiven Proteinen wie (bakteriellen) Hydrophobinen, könnten aufgrund ihrer spezifischen Wechselwirkungen mit der Luft-Wasser-Grenzfläche Tenside als Schaumbildner ersetzen und eine Generalisierung der Methode ermöglichen. Vor diesem Hintergrund war es das Ziel der vorliegenden Arbeit, Fusionsproteine zu identifizieren, die eine tensidfreie, aktivitätserhaltende Schaumfraktionierung von Enzymen ermöglichen. Die Identifikation potenzieller struktureller Determinanten der Fusionsproteine, die die Aufrechterhaltung der Aktivität und die Anreicherung im Schaum bedingen, bilden eine wichtige Grundlage

Silyl ether protecting groups are important tools in organic synthesis, ensuring selective reactions of hydroxyl functional groups. Enantiospecific formation or cleavage could simultaneously enable the resolution of racemic mixtures and thus significantly increase the efficiency of complex synthetic pathways. Based on reports that lipases, which today are already particularly important tools in chemical synthesis, can catalyze the enantiospecific turnover of trimethylsilanol (TMS)-protected alcohols, the goal of this study was to determine the conditions under which such a catalysis occurs. Through detailed experimental and mechanistic investigation, we demonstrated that although lipases mediate the turnover of TMS-protected alcohols, this occurs independently of the known catalytic triad, as this is unable to stabilize a tetrahedral intermediate. The reaction is essentially non-specific and therefore most likely completely independent of the active site. This rules out lipases as catalysts for the resolution of racemic mixtures of alcohols through protection or deprotection with silyl groups.

Agar is a marine heteropolysaccharide with repeating units consisting of 3,6-α-anhydro-L-galactopyranose and D-galactopyranose linked by α-(1,3) and β-(1,4) linkages. It has been promoted as a prospective replacement for petroleum-based feedstocks and other applications. Enzymatic biotransformation of agar generates high specific products: It is also more environmentally friendly than chemical hydrolysis. In particular, agarolytic bacteria and their agarases are preferred for the processing of agar into sugar derivatives. Agar-producing macroalgae are one of Indonesia's national commodities. However, agar-based products and technology are rarely developed in Indonesia. This research is aimed to explore the potential of an Indonesian marine bacterium and its agarases as bioagents for agar bioprocessing. The research objectives are to identify the novelty of the isolate among known agarolytic bacteria using microbiology and molecular biology approaches, to elucidate the agarolytic system of the bacterium using in silico genome analysis, to express and characterize the recombinant agarases, and to elucidate their potential for producing agar-derived saccharides from Indonesian natural agar. Microbulbifer elongatus PORT2 is a gram-negative marine bacterium that had been isolated from Batu Karas seawater, Pangandaran, West Java Indonesia. PORT2 shows potential as biocatalysts for agar saccharides conversion by showing remarkable agar liquefaction. The annotation of the draft genome identifies six putative β-agarases consist of three GH50, two GH86, and one GH16 in M. elongatus PORT2. Those agarases are clustered at two different contigs. Besides agarases, other genes for D-galactose and 3,6 anhydro-L galactose metabolism, sugar transports and regulatory system are found in the vicinity of the agarases clusters. Despite the ability to utilize agar as a sole carbon sole, PORT2 lacks any putative α-agarase GH117 or GH96. Both are responsible for the cleavage of α-glycosidic