biocatalysis Dotaz Zobrazit nápovědu

Pentacyclic triterpenes are important representatives of natural products that exhibit a wide variety of biological activities. These activities suggest that these compounds may represent potential medicines for the treatment of cancer and viral, bacterial, or protozoal infections. Naturally occurring triterpenes usually have several drawbacks, such as limited activity and insufficient solubility and bioavailability; therefore, they need to be modified to obtain compounds suitable for drug development. Modifications can be achieved either by methods of standard organic synthesis or with the use of biocatalysts, such as enzymes or enzyme systems within living organisms. In most cases, these modifications result in the preparation of esters, amides, saponins, or sugar conjugates. Notably, while standard organic synthesis has been heavily used and developed, the use of the latter methodology has been rather limited, but it appears that biocatalysis has recently sparked considerably wider interest within the scientific community. Among triterpenes, derivatives of lupane play important roles. This review therefore summarizes the natural occurrence and sources of lupane triterpenoids, their biosynthesis, and semisynthetic methods that may be used for the production of betulinic acid from abundant and inexpensive betulin. Most importantly, this article compares chemical transformations of lupane triterpenoids with analogous reactions performed by biocatalysts and highlights a large space for the future development of biocatalysis in this field. The results of this study may serve as a summary of the current state of research and demonstrate the potential of the method in future applications.

Článek

Biocatalysis: "A Jack of all Trades

International journal of molecular sciences. 2020 ; 21 (14) : . [pub] 20200720

Int J Mol Sci
ISSN 1422-0067
Medvik
Zdroj

Biotransformation has accompanied mankind since the Neolithic community, when people settled down and began to engage in agriculture [...].

Článek

Progress in biocatalysis with immobilized viable whole cells: systems development, reaction engineering and applications

Biotechnology letters. 2017 ; 39 (5) : 667-683. [pub] 20170208

Biotechnol Lett
ISSN 1573-6776
Medvik
Zdroj

Viable microbial cells are important biocatalysts in the production of fine chemicals and biofuels, in environmental applications and also in emerging applications such as biosensors or medicine. Their increasing significance is driven mainly by the intensive development of high performance recombinant strains supplying multienzyme cascade reaction pathways, and by advances in preservation of the native state and stability of whole-cell biocatalysts throughout their application. In many cases, the stability and performance of whole-cell biocatalysts can be highly improved by controlled immobilization techniques. This review summarizes the current progress in the development of immobilized whole-cell biocatalysts, the immobilization methods as well as in the bioreaction engineering aspects and economical aspects of their biocatalytic applications.

Článek

Bioproduction of Quercetin and Rutinose Catalyzed by Rutinosidase: Novel Concept of "Solid State Biocatalysis"

International journal of molecular sciences. 2019 ; 20 (5) : . [pub] 20190305

Int J Mol Sci
ISSN 1422-0067
Medvik
Zdroj

Quercetin is a flavonoid largely employed as a phytochemical remedy and a food or dietary supplement. We present here a novel biocatalytic methodology for the preparation of quercetin from plant-derived rutin, with both substrate and product being in mostly an undissolved state during biotransformation. This "solid-state" enzymatic conversion uses a crude enzyme preparation of recombinant rutinosidase from Aspergillus niger yielding quercetin, which precipitates from virtually insoluble rutin. The process is easily scalable and exhibits an extremely high space-time yield. The procedure has been shown to be robust and was successfully tested with rutin concentrations of up to 300 g/L (ca 0.5 M) at various scales. Using this procedure, pure quercetin is easily obtained by mere filtration of the reaction mixture, followed by washing and drying of the filter cake. Neither co-solvents nor toxic chemicals are used, thus the process can be considered environmentally friendly and the product of "bio-quality." Moreover, rare disaccharide rutinose is obtained from the filtrate at a preparatory scale as a valuable side product. These results demonstrate for the first time the efficiency of the "Solid-State-Catalysis" concept, which is applicable virtually for any biotransformation involving substrates and products of low water solubility.