The present invention relates to a recombinant organism or microorganism having a decreased pool of crotonic acid compared to the organism or microorganism from which it is derived due to at least one of: (i) an increased conversion of crotonyl-CoA into butyryl-CoA; and/or an increased conversion of butyryl-CoA into butyric acid; (ii) an increased conversion of crotonyl-CoA into 3-hydroxybutyryl-CoA; and/or an increased conversion of 3-hydroxybutyryl-CoA into 3-hydroxybutyric acid; (iii) an increased conversion of crotonic acid into crotonyl-CoA; (iv) an increased conversion of crotonyl-[acyl-carrier protein] into butyryl [acyl-carrier-protein]; (v) a decreased conversion of crotonyl-CoA into crotonic acid; and/or (vi) a decreased conversion of crotonyl-[acyl-carrier protein] into crotonic acid. Moreover, the present invention relates to the use of such a recombinant organism or microorganism for the production of alkenes with the enzyme ferulic acid decarboxylase. Further, the present invention relates to a method for the production of isobutene or butadiene by culturing such a recombinant organism or microorganism in a suitable culture medium under suitable conditions.