Biotransformation of 2,6‐diaminopurine nucleosides by immobilized Geobacillus stearothermophilus

Abstract

An efficient and green bioprocess to obtain 2,6-diaminopurine nucleosides using thermophilic bacteria is herein reported. Geobacillus stearothermophilus CECT 43 showed a conversion rate of 90 and 83% at 2 h to obtain 2,6-diaminopurine-2'-deoxyriboside and 2,6-diaminopurine riboside, respectively. The selected biocatalyst was successfully stabilized in an agarose matrix and used to produce up to 23.4 g of 2,6-diaminopurine-2'-deoxyriboside in 240 h of process. These nucleoside analogues can be used as prodrug precursors or in antisense oligonucleotide synthesis.

Characterization of an atypical, thermostable, organic solvent- and acid-tolerant 2′-deoxyribosyltransferase from Chroococcidiopsis thermalis

“…Due to the low solubility of some purine bases, such as guanine, xanthine, or other modified purines, the enzymatic synthesis of purine nucleoside analogues from poorly soluble purine bases has been described to be less efficient. To overcome this drawback, many different strategies have been employed, such as raising the pH and/or the temperature (Crespo et al 2017;De Benedetti et al 2012;Del Arco et al 2017;Okuyama et al 2003;Yokozeki and Tsuji 2000), or adding organic solvents (Fernández-Lucas et al 2012), and the effect of water-organic co-solvent mixtures on the enzymatic activity and stability of several NDTs has been extensively documented (Castro and Knubovets 2003;Fernández-Lucas et al 2012). In this regard, several factors such as the denaturing capacity (Khmelnitsky et al 1991), the polarity index (Gupta et al 1997), the dielectric constant (Kaul and Banerjee 2008), the log P value (Arroyo et al 2000), and the Dimroth-Reichardt parameter (Moreno and Fágáin 1997) have been considered in general with limited success.…”

Bioproduction of ribavirin by green microbial biotransformation

“…It is well known that transglycosylation reactions are reversible [26] and previous reports have demonstrated that using an excess of any substrate significantly improved conversion values [27]. In this case, a base excess promotes the second reaction step (Scheme 1) shifting equilibrium towards products by taking R-1-P available and turning it into ribavirin.…”

“…Scale-up bioprocesses for ribavirin biosynthesis using batch and packed-bed reactors. Environmental factors were calculated as previously reported [27].…”

Biocatalytic approaches applied to the synthesis of nucleoside prodrugs

“…Chemoenzymatic approaches (a, b, c) to prepare Abacavir from Diels-Alder cycloaddition of cyclopentadiene. and agarose-entrapped whole cells (Nóbile et al, 2010), as well as cloned and overexpressed free enzymes (Ubiali et al, 2012), thermostable Geobacillus stearothermophilus (De Benedetti et al, 2012) and Aeropyrum pernix K1 (Zhu et al, 2013).…”