Fig 4.

Degradation of TAA and 2-methyl-3-buten-2-ol by resting cells of wild-type strain L108 (closed symbols) and the L108(ΔmdpJ) K2 knockout mutant strain (open symbols). (A) Isoamylene, as the sum of gamma- and beta-isomers (diamonds), was formed from TAA (squares). In all cases, mainly beta-isoamylene was emitted, representing 96 to 97% of the alkenes produced (data not shown). In addition, the accumulation of small amounts of 2-methyl-3-buten-2-ol (triangles) from TAA with the wild-type strain but not with the mutant was observed. (B) Isoprene (diamonds) was formed from 2-methyl-3-buten-2-ol (triangles). For a direct comparison with alcohol conversion, values of dehydration products refer to concentrations in the liquid phase, although they were found exclusively in the gas phase of the closed incubation bottles.