Plants as Enzyme Factories

Abstract

In this chapter, we focus on the production of enzymes and other commercially valuable proteins in transgenic plants. Enzymes are ideal for use as catalysts in industrial processes because they can function in aqueous solutions at ambient temperatures and neutral or physiologic pH levels. Furthermore, enzymes have a high specificity, low toxicity, and catalyse reactions relatively quickly at low concentrations. However, temperature and pH extremes can limit enzymatic activity, and certain ions, organic molecules and solvents can inactivate enzymes. Such conditions are often present in large‐scale industrial processes so significant changes are required when moving from chemical to enzymatic catalysts. Nevertheless, the large market opportunity for industrial enzymes and the environmental benefits they provide offer the incentive to invest in the development of efficient production systems and to make the necessary changes in industrial processes.

Plant biotechnology for lignocellulosic biofuel production

“…The yield of transgene products is affected by the genetic characteristics of the transgenes, in particular (i) codon usage in host plants, (ii) the promoter used for expression and (iii) the encoded signal peptides for subcellular localization (Hood, ; Hood et al ., , ; Streatfield, ). Cellulases from bacteria, such as Acidothermus cellulolyticus and Trichoderma reesei , have been expressed in many plant species, including Arabidopsis, tobacco and alfalfa (Table ).…”

Molecular farming: strategies, expression systems and bio-safety considerations

“…Even if the expression level of protein in maize is 1% of dry weight and its recovery is only 50%, the cost of its production may still be only 2-10% of microbial systems and may be even lower than that for mammalian systems (Twyman et al 2003;Chen et al 2005). It has been estimated that at 20% total soluble seed protein expression level, one bushel (25 kg) of maize can produce the same amount of avidin as one tonne of chicken eggs and the cost is only 0.5% of that of chicken eggs (Hood 2004). Several companies at the moment are involved in the commercial production of plant made recombinant proteins.…”