and Sphingobium sp. The results show that aerobic microbial granules based process is suitable for the treatment selleck of dibutyl phosphite contaminated water. “
“This work describes an efficient, simple, and green bioprocess for obtaining 5-halogenated pyrimidine nucleosides from thymidine by transglycosylation using whole cells. Biosynthesis of 5-fluoro-2′-deoxyuridine (floxuridine) was achieved by free and immobilized Aeromonas salmonicida ATCC 27013 with an 80% and 65% conversion occurring

in 1 h, respectively. The immobilized biocatalyst was stable for more than 4 months in storage conditions (4 °C) and could be reused at least 30 times without loss of its activity. This microorganism was able to biosynthesize 2.0 mg L−1 min−1 (60%) of 5-chloro-2′-deoxyuridine in 3 h. These halogenated pyrimidine 2′-deoxynucleosides are used as antitumoral agents. Nucleosides have been considered of great interest because they have shown activity against various cancer

cell lines in vitro and in vivo. Nucleosides and their analogues are implicated in the modulation of several signal transduction pathways causing growth inhibition, differentiation, apoptosis, and modulation of gene expression through different mechanisms of action (Wang et al., 2004; Rossi et al., 2009; Li et al., 2010). Therefore, nucleoside analogues can be used as powerful antitumoral agents. Halogenated derivatives are high throughput screening compounds widely recognized today as an effective cancer treatment. The efficacy of fluorinated derivatives for the treatment of several cancer modalities is well known (Cantero et al., 2006; Bronckaers et al., 2008). Floxuridine or 5-fluoro-2′-deoxyuridine has shown activity in patients with colorectal, pancreatic, breast, head, and neck cancers (Liu et al., 2008). Many studies have demonstrated that Inositol monophosphatase 1 5-chloro-2′-deoxyuridine is useful in cancer treatment (Morris, 1993). Moreover, 5-fluoro-2′-deoxyuridine and 5-chloro-2′-deoxyuridine have been useful as substrates to design new prodrugs (Johar et al.,

2005; Park et al., 2009). Biocatalysis is frequently recognized as superior to conventional chemical methods in selective modification of polyfunctional substrates owing to high catalytic efficiency, inherent selectivity, and simple downstream processing. In addition, biotransformations take place under very mild conditions and offer environmentally clean technologies (Qian et al., 2008). Transglycosylation is catalyzed by nucleoside phosphorylases. These enzymes catalyze reversible phosphorolytic cleavage of N-glycosidic bonds of nucleosides without addition of ATP, to form a free base and its respective activated pentose moiety, which is then coupled to the desired modified base to give a nucleoside analogue (only β-anomer; Bzowska et al., 2000). Halogenation is usually applied to organic structures in order to confer or enhance antitumoral activity.