A new concept based on own experimental results and published data and concerning the involvement under extreme conditions of additional (nontraditional) mechanisms of formaldehyde, formate and hydrogen peroxide detoxification in methylotrophic yeast has been proposed. It has been shown that neutralization of toxic effect of formaldehyde and formate, except the known ways, includes a system of energy-dependent extrusion of formic acid into extracellular space. Detoxification of hydrogen peroxide, besides of catalase way, can be realized by means of cytochrome c peroxidase reaction. The proposed concept has been built on the basis of physiological and biochemical analysis of specially constructed mutants strains of methylotrophic yeast with certain metabolic damages. The selected mutants, used as the instrument in fundamental studies of detoxification processes, also have been successfully used for practical purposes in construction of cell biosensors and creation of enzymatic kits.