The use of trehalose-stabilized lyophilized methanol dehydrogenase from Hyphomicrobium X for the detection of methanol.

The enzyme methanol dehydrogenase (EC 1.1.99.8) from Hyphomicrobium X was used in an attempt to develop a rapid colorimetric test for methanol. The enzyme was stabilized for storage by lyophilization in the presence of the disaccharide trehalose. It was found that the enzyme retained significantly greater activity in the dried state with trehalose than without. The enzyme was partially purified by ammonium sulphate fractionation, after which it was found to be more stable in solution at pH 9 than at pH 7. A procedure is given which involves mixing a defined amount of enzyme with the methanol-containing water together with phenazine methosulphate (PMS), 2-6-dichlorophenol-indophenol (DCPIP) and cyanide, and observing the resultant colour change from blue to yellow if methanol is present. The sensitivity of the procedure is such that 9 mg L-1 of methanol can be readily detected.