Team:Slovenia/PROJECT/biosynthesis

Chuck Norris facts:

Introduction

Biosynthesis is an enzyme catalyzed process, occurring in living cells, by which simple substrate molecules are converted into more complex products. The process often consists of several steps, in which the product of one step is used as a substrate for the following step. In synthetic biology, research and engineering of biosynthetic pathways gains more and more attention every year. One of the first great stories in the field of synthetic biology was engineering the artificial biosynthetic pathway for antimalarial drug artemisinic acid production in Saccharomyces cerevisae yeast. Production of  artemisinic acid in genetically modified yeasts was achieved modulating regulation of specific mevalonate pathway genes and by the introduction of genes for the biosynthetic pathway from Artemisia annua plant to yeast. Another great examples of biosynthetic pathway engineering are production of fatty esters (biodiesel), fatty alcohols, and waxes by genetically modified Escherichia coli. Genes from different organisms were combined into completely new pathway which was introduced to Escherichia coli  to produce useful fuel directly from plant biomass.

For industrial applications biosynthetic pathways composed of several enzymes should be engineered in a way to achieve high yield of the desired biosynthetic products. Various strategies for optimization have been undertaken so far, such as:

• Increasing the pool of available substrate and/or overexpression of the enzymes of the limiting biosynthetic steps,
• Introducing heterologous enzymes with preferred kinetic characteristics,
• Blocking branching of biosynthetic pathway,
• Compartmentalizing of biosynthetic pathways by directing enzymes of a particular biosynthetic pathway to a specific cell compartments or artificially made compartments (e.g. metabolosomes),
• Increasing the proximity of enzymes by assembling metabolic pathways on a protein scaffold.

Scaffold-assisted biosynthetic pathway