A thermostable pyrimidine nucleoside phosphorylase from Brevibacillus borstelensis LK01 for synthesizing halogenated nucleosides

Objective To isolate a thermostable pyrimidine nucleoside phosphorylase (PyNP) from mesophilic bacteria by gene mining. Results Bb PyNP from Brevibacillus borstelensis LK01 was isolated by gene mining. Bb PyNP had a highest 60% identity with that of reported PyNPs. Bb PyNP could catalyze the phosphorolysis of thymidine, 2′-deoxyuridine, uridine and 5-methyuridine. Bb PyNP had good thermostability and retained 73% of its original activity after 2 h incubation at 50 °C. Bb PyNP had the highest activity at an optimum alkaline pH of 8.5. Bb PyNP was stable from pH 7 to 9.8. Under preliminary optimized conditions, the biosynthesis of various 5-halogenated pyrimidine nucleosides by Bb PyNP reached the yield of 61–84%. Conclusion An efficient approach was estimated in isolating thermostable PyNP from mesophilic bacteria.