Expression of esterase genes in plant cells results in the production of enzymatically active esterases that effectively resists the otherwise growth inhibitory and/or lethal effects of nonionic, fatty acid ester detergents such as Tween 20 or Span 20. Specifically, expression of a variety of esterases, including pregastric esterase, carboxyesterase, lipase and acyloxyacyl hydrolase from a wide variety of sources in plant cells is disclosed as an excellent method to protect the cells from the effects of these detergents, allowing the exposed plant cells to regenerate into whole plants in the presence of nonionic, fatty acid ester detergents, thereby providing a practical and safe method for plant transformation.