Abstract
S-hydroxymethylglutathione dehydrogenase from Paecilomyces variotii No. 5 strain (NBRC 109023), isolated as a formaldehyde-degrading fungus, was purified by a procedure that included ammonium sulfate precipitation, DEAE-Sepharose and hydroxyapatite chromatography and isoelectrofocusing. Approximately 122-fold purification was achieved with a yield of 10.5%. The enzyme preparation was homogeneous as judged by sodium dodecyl polyacrylamide gel electrophoresis (SDS-PAGE). The molecular mass of the purified enzyme was estimated to be 49 kDa by SDS-PAGE and gel filtration, suggesting that it is a monomer. Enzyme activity was optimal at pH 8.0 and was stable in the range of pH 7.0–10. The optimum temperature for activity was 40°C and the enzyme was stable up to 40°C. The isoelectric point was pH 5.8. Substrate specificity was very high for formaldehyde. Besides formaldehyde, the only aldehyde or alcohol tested that served as a substrate was pyruvaldehyde. Enzyme activity was enhanced by several divalent cations such as Mn2+ (179%), Ba2+ (132%), and Ca2+ (112%) but was completely inhibited by Ni2+, Fe3+, Hg2+, p-chloromercuribenzoate (PCMB) and cuprizone. Inactivation of the enzyme by sulfhydryl reagents (Hg2+ and PCMB) indicated that the sulfhydryl group of the enzyme is essential for catalytic activity.
Highlights
Formaldehyde is a ubiquitous compound that is a product of biological sources (Levy 1971; Zimmerman et al 1978) and environmental sources (Ando 1998)
An advanced technology for potable water pretreatment includes ozonation, during which formaldehyde is generated as a result of the reaction of ozone with traces of humus (Schechter and Singer 1995)
Microorganism, media and culture conditions P. variotii NBRC 109023, which was isolated from soil and can degrade a high concentration of formaldehyde (2.4%) was used
Summary
Formaldehyde is a ubiquitous compound that is a product of biological sources (from photooxidation of atmospheric hydrocarbons) (Levy 1971; Zimmerman et al 1978) and environmental sources (emissions from industrial processes) (Ando 1998). An advanced technology for potable water pretreatment includes ozonation, during which formaldehyde is generated as a result of the reaction of ozone with traces of humus (Schechter and Singer 1995). Formaldehyde acts as disinfectant at concentrations as low as 0.1%. It is used for room sterilization, viscosity stabilization and preservation of adhesives made from starch and for preservation of. To address the problem of formaldehyde pollution, we attempted to isolate a microorganism that can degrade formaldehyde. We isolated a fungus that can degrade concentrations of formaldehyde as high as 2.4%. The fungus belongs to the genus Paecilomyces (Iwahara et al 2002). After determining the DNA sequence of the 18 S ribosomal RNA gene of this fungus, we named it Paecilomyces variotii No 5 (NBRC 109023)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
