1,721,368 research outputs found
Biocatalysis for use in pharmaceutical manufacturing
No full textThe major goal of our research is the development of synthetically useful selective biotransformations using microbial enzymes by combining natural and non-natural conditions. Biotransformations to be used in pharmaceutical manufacturing has been studied.
Examples from our work will be presented with regards to these strategies, including different applications:
➢ Selective modification of antibiotics (deacylation and demannosilation) by using hydrolases from actinomycetes
➢ Chemo- and enantioselective oxidations and reductions for the production of optically pure intermediates to be used for the synthesis of different drugs
Different techniques have been exploited for improving the selectivity and/or productivity of the bioprocesses: medium manipulation (e.g. binding agents or organic solvents), biocatalyst manipulation and reactor engineering
New Enantioselective Microbial Esterases
No full textThe major goal of our research is the development of synthetically useful selective biotransformations using “new” microbial enzymes by combining natural and non-natural conditions. Enantioselective hydrolysis of chiral or prochiral esters can be used in different fields (i.e. pharma, agrofood, materials) for obtaining optically pure alcohols or carboxylic acids.
While a number of lipases is commercially available as free or immobilized enzymes, esterase are much less studied, although they show interesting features, such as:
Esterases show chemo-, regio- and stereoselectivity alternative or complementary to the ones displayed by lipases
Esterases are much less used for the synthesis of optically pure product and their commercial availability limited.
We have built-up a library of 75 microoganisms belonging to different genera having cell-associated esterases selected after screenings carried out on chiral esters of primary alcohols which are hydrolysed with low enantioselectivity by commercial lipases.
New cell-bound carboxylesterases from bacteria (i.e. Bacillus coagulans, Streptomyces sp.) and yeasts (i.e. Kluyveromyces marxianus, Pichia sp.) have been studied and partially characterised. They have been employed for different enantioselective hydrolysis of chiral esters (i.e. solketal and aminoacid esters), not easily and/or efficiently resolved with commercial enzymes. Different strategies of optimisation and development of processes yielding multi-gram scale production will be also discussed
Preparation of glycolipo(depsi)peptides derivatives by biocatalysis
No full textFocus of our research is the development of synthetically useful selective biotransformations utilizing microbial enzymes by combining natural and non-natural conditions. The presentation will deal with biotransformations as a way to generate novel glycolipo(depsi)peptide-like molecules.
There are several reasons why it is important to produce derivatives of glycolipopeptide antibiotics obtained by fermentation: i.e. to better pharmacokinetics and/or pharmacodynamics, to cope with emerging resistance among gram-positive pathogens, to reduce undesirable possible side-effects. Selective hydrolysis of the fatty acid chain and/or of the sugar residues in glycolipo(depsi)peptides have been studied by chemical means, but the presence of other hydrolysable groups (i.e. the peptide bonds or the lactone in the cyclic core of these molecules) makes conventional chemistry rather complicated.
Biocatalysis offers a valid alternative for performing chemo- and regio-selective hydrolysis of acyl or glycosydic bonds under mild conditions of pH, temperature and pressure. Unfortunately, commercial enzymes proved not to be useful for these modifications. Therefore, non commercial enzymes and new enzymatic activities with activity towards glycolipo(depsi)peptide have been explored using different screening approaches..
Examples from our work will be presented by including different applications:
Deacylation of glycolipopeptide antibiotics (i.e dalbavancin, A40926)
Deacylation of ramoplanin
Demannosilation of ramoplanin
These biotransformations have been accomplished on preparative scale using enzymes/whole cells from different species of actinomycete
Oxidations with isolated and cell-bound dehydrogenases and oxidases
No full textOxidations catalyzed by microbial dehydrogenases and oxidases allow for transformation of different molecules (primary and secondary alcohols, aldehydes, amines, saturated compounds) with high chemo-, regio- and enantioselectivity. Although only few bio-oxidations have been developed on large scale, the use of dehydrogenases and oxidases can be seen as a complementary tool to conventional synthetic methods. This review shows the advantages and the limitations of bio-oxidations catalyzed by whole microbial cells and/or isolated enzymes, with particular emphasis on the problem of cofactor recycling. The representative examples have been chosen trying to highlight how the problems of low selectivity or productivity can be overcome by using different techniques, such as the use of isolated enzymes and addition of coenzymes coupled with systems for regeneration of the coenzymes, genetic modification of the microorganism for knocking-out the degrading enzymes, recombination of the oxidative enzyme of interest in hosts with no overmetabolism, in situ extraction of the product, employment of microorganisms with "incomplete" oxidative metabolism, use of synthetic substrates leading to product not further modifiable
Biocatalysis for the manufacture of pharma intermediates
No full textThe major goal of our research is the development of synthetically useful selective biotransformations using microbial enzymes by combining natural and non-natural conditions. Biotransformations to be used in pharmaceutical manufacturing has been studied.
Examples from our work will be presented with regards to these strategies, including different applications:
➢ Selective modification (deacylation and demannosilation) of lipoglycopeptide antibiotics by using hydrolases from actinomycetes. Case study: modification of ramoplanin
➢ Chemo- and enantioselective oxidations for the production of optically pure intermediates to be used for the synthesis of different drugs. Case study: chemoenzymatic synthesis of Captopril®
Different techniques have been exploited for improving the selectivity and/or productivity of the bioprocesses: reaction engineering, biocatalyst manipulation and reactor engineering
Enzymatic synthesis of (S)-1,2-O-isopropylidene glycerol
No full textThis invention relates to a process for the synthesis of (S)-1,2-O-isopropylidene glycerol by hydrolysis of a racemic mixture of (R,S)-1,2-O-isopropylidene glycerol acetate catalysed by Kluyveromyces marxianus, recovery of unreacted (R)-1,2-O-isopropylidene glycerol acetate, and hydrolysis thereo
Reduction of carbonylic and carboxylic group's by plant cell cultures
No full textThe transformation of aliphatic and aromatic acids to their corresponding alcohols, involving two reductive steps, is difficult to perform biologically due to its low redox potential. For this reason, the reduction of nonactivated carboxylic acids has been described for only a limited number of substrates and confined to a few microbial groups (fungi, clostridia, and archea). Nine species of cultured plant cells were able to reduce cinnamic, hexanoic, and octanoic acids to the corresponding primary alcohols with yields ranging from 2 to 80% (w/w). Aldehyde was detected only for three species during the reduction of cinnamic acid, confirming that the second reductive step from aldehyde to alcohol is faster than the first, from acid to aldehyde. Lyophilized cells from some of the cultures were used in buffer and solvent-water systems to obtain the reduction of carbonylic (ethyl acetoacetate) and carboxylic (cinnamic and hexanoic acids) groups
Production of optically pure molecules by biotransformation of agro-food wastes.
No full textBiocatalysis is nowadays an established technology for the production of chemicals. Biotransformations are performed under mild conditions and can be highly selective; Biocatalysts are currently employed for the production of products in different fields, such as pharmaceuticals or intermediate for their production (e.g., antibiotics, statins, enantiomerically pure building blocks), fine chemicals (e.g., aminoacids, vitamins) and food manufacture (e.g., sweeteners, lipids, nutraceuticals). Stereoselectivity is a key-issue in most of the bioprocesses developed for transformations of organic molecules. Methods based on biocatalysis can further broaden their applicability and meet criteria of sustainability if efficiently employed for the transformation of cheaply available agro-food wastes and surplus, such as starch, molasses, cheap proteins and lipids. The application of recombinant technologies and protein engineering has dramatically widened the potential of biotransformations. Examples of classical and new bioprocesses are reported, highlighting the improvements given by an integrated application of different strategies (molecular biology, extractive systems, immobilization etc.) for their optmization
Novel enantioselective enzymes from non-conventional yeasts
No full textThe major goal of my research is the development of synthetically useful selective biotransformations using “new” microbial enzymes by combining natural and non-natural conditions.
In this poster will be presented results from research activities on three different class of enzymes:
● Carboxylesterases – A new cell-bound carboxylesterase from Kluyveromyces marxianus have been purified and partially characterised. It has been employed for different enantioselective hydrolysis of chiral esters (i.e. solketal and aminoacid esters), not easily and/or efficiently resolved with commercial enzymes. Different strategies of optimisation and development of processes yelding multi-gram scale production will be also discussed.
Ref. Daniela Monti, Erica Elisa Ferrandi, Monica Righi, Diego Romano, Francesco Molinari. Purification and characterization of the enantioselective esterase from Kluyveromyces marxianus CBS 1553. Journal of Biotechnology (2008), 133(1), 65-72.
● Dehydrogenases - Pichia glucozyma produces DHs able to reduce aromatic ketones with peculiar stereodifferentiation between the prostereogenic faces of the carbonyls. Different aromatic substrates were reduced with high molar conversions and excellent stereoselectivity; the stereoselectivity was often complementary to the one observed with organometallics. The presence of different dehydrogenases in Pichia glucozyma allowed also for the deracemization of different racemic benzoins and α-substituted carbonyls.
Ref. Syed Masood Husain, Thomas Stillger, Pascal Dünkelmann, Melanie Lödige, Lydia Walter, Elke Breitling, Martina Pohl, Mara Bürchner, Ingo Krossing, Michael Müller, Diego Romano, Francesco Molinari, Stereoselective reduction of 2-hydroxy ketones towards syn- and anti-1,2-Diols – Accepted for publication in Advanched Sinthesys and Catalisys
R. Gandolfi, E. Cesarotti, F. Molinari, D. Romano, I. Rimoldi. Asymmetric reductions of ethyl 2-(benzamidomethyl)-3-oxobutanoate by yeasts
Tetrahedron: Asymmetry 2009, 20, 411-414.
● Enoate Reductases (OYEs) - Old Yellow Enzymes are flavin-dependent oxidoreductases that catalyze the stereoselective trans-hydrogenation of electron-poor alkenes (enoate reductase activity), which can result in important chiral synthons toward synthesis of many pharmaceuticals and chemicals. In this study, environmental yeasts have been screened for OYE activity with the purpose to develop new enoate reductase biocatalyst. Recombinant strains with enhanced OYE activity have been obtained and could be exploited for production of purified enzyme. Furthermore, the data herein reported attract interest due to promising applications in asymmetric synthesis.
Ref. Stefano Raimondi, Diego Romano, Alberto Amaretti, Francesco Molinari and Maddalena Rossi. Enoate reductases from non conventional yeasts as novel biocatalysts: cloning and functional expression in Saccharomyces cerevisiae.
Submitted at Journal of Biotechnolog
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