Nonenzymatic chemical reactions spontaneous

Biological. In both soils and water, chemical and biological mediated reactions can transform thiram to compounds containing the mercaptan group (Alexander, 1981). Odeyemi and Alexander (1977) isolated three strains of Rhizobium sp. that degraded thiram. One of these strains, Rhizobium meliloti, metabolized thiram to yield dimethy-lamine (DMA) and carbon disulfide which formed spontaneously from dimethyldithiocar-bamate (DMDT). The conversion of DMDT to DMA and carbon disulfide occurred via enzymatic and nonenzymatic mechanisms (Odeyemi and Alexander, 1977). 

Two particular problems which are often encountered in hydroxynitrile lyase-catalyzed reactions are the spontaneous nonenzymatic formation of racemic cyanohydrin and racemization of the product due to equilibration of the reaction. As a result, the optical purity of the product is decreased. Bearing in mind that both the chemical formation and the racemization of cyanohydrins are pH-dependent and require water, three different techniques have been developed in order to suppress the reduction of the optical purity of the product. 

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