The most common route to produce aromatic chemicals - organic compounds 
containing at least one benzene ring in their structure - is chemical synthesis. 
These processes, usually starting from an extracted fossil oil molecule such as 
benzene, toluene, or xylene, are highly environmentally unfriendly due to the 
use of non-renewable raw materials, high energy consumption and the usual 
production of toxic by-products. An alternative way to produce aromatic 
compounds is extraction from plants. These extractions typically have a low 
yield and a high purification cost. This motivates the search for alternative 
platforms to produce aromatic compounds through low-cost and environmentally 
friendly processes. Microorganisms are able to synthesize aromatic amino acids 
through the shikimate pathway. The construction of microbial cell factories able 
to produce the desired molecule from renewable feedstock becomes a promising 
alternative. This review article focuses on the recent advances in microbial 
production of aromatic products, with a special emphasis on metabolic 
engineering strategies, as well as bioprocess optimization. The recent 
combination of these two techniques has resulted in the development of several 
alternative processes to produce phenylpropanoids, aromatic alcohols, phenolic 
aldehydes, and others. Chemical species that were unavailable for human 
consumption due to the high cost and/or high environmental impact of their 
production, have now become accessible.