A new recombinant plasmid, pBZIP1, was constructed for heterologous expression of high levels of ice nucleation activity in ethanol-producing Zymomonas mobilis strains CP4 and NCIB 11163. The plasmid construct contained the mobilization region and tetracycline resistance gene of pBR325, the replication region of the Z. mobilis native plasmid pZMO3 and the Pseudomonas syringae ice nucleation gene under the control of the Z. mobiiis CP4 pyruvate decarboxylase promoter (P-pdc). Z. mobilis transconjugants retained the plasmid stably, expressed ice nucleation activity up to 0.73 log [ice nuclei/cell] and can be used as improved sources of ice nuclei for industrial applications.