Expression of Cell Wall-Modifying Enzymes in Aspen for Improved Lignocellulose Processing

Wood is an important source of biomass for materials and chemicals, and a target for genetic engineering of its properties for different applications or for research. Wood properties can be altered by using different enzymes acting on cell wall polymers postsynthetically in cell walls. This approach allows for a precise polymer structure modification thanks to the specificity of enzymes used. Such enzymes can originate from all kinds of organisms, or even be modified in a desired way for novel attributes. Here we present a general strategy for expressing a microbial enzyme in aspen and targeting it to cell wall, using an example of fungal glucuronoyl esterase. We describe methods of vector cloning, plant transformation, transgenic line selection and multiplication, testing for the presence of enzymatic activity in different cell compartments, and finally the method of plant transferring from sterile culture to the greenhouse conditions.