**1. Introduction**

Sustainable production of industrial chemicals requires the use of biomass as a raw material, which can be converted into intermediate chemicals, currently being used as raw materials derived from non-renewable feedstocks, such as coal, crude oil, natural gas, etc. This allows the chemical industry to preserve its current petrochemical plants, except changing its source of feedstock from nonrenewable sources to renewable materials, such as biomass. The challenges posed by shifting to renewable feedstocks involve new chemistries which convert a variety of biomass materials into the known feedstocks, and in some cases starting with completely different raw materials. In addition, biomass conversions by fermentation involve slow reactions, conducted in the liquid phase, with low conversions, resulting in dilute aqueous solutions.

Traditionally, the chemical industry has relied on gas phase, catalytic, high temperature, and often high-pressure reactions, which require short residence times in

smaller reactors and produce a high concentration of product(s). In comparison, biomass conversions using fermentation are biological, liquid-phase reactions, conducted at near ambient temperature and usually atmospheric pressure. The reaction rates in fermentation chemistry are orders of magnitude lower than in gas-phase chemical conversions.

Notwithstanding these challenges, in this chapter, known reactions for converting a variety of biomass sources into known chemical feedstocks have been detailed. Conversion and yield information from the publications of these chemical reactions was used to generate and rank these reactions based on their carbon economy. Carbon economy is the ratio of the mass of carbon atoms in the feedstock produced to the mass of carbon atoms present in the biomass source. By maximizing the carbon economy, the mass of carbon atoms present in the waste product(s) is minimized.

In addition, chemical reaction pathways, currently used to manufacture the top 100 industrial chemicals from nonrenewable feedstocks, were derived from known sources [1–4], and each reaction pathway was also evaluated by its carbon economy. A computer program was developed to link the biomass conversion reactions with the industrial chemical pathways, with the objective of maximizing the overall carbon economy starting with the biomass material and ending with the industrial chemical. This provided multiple reaction pathways, in order of decreasing the overall carbon economy, to convert a biomass feedstock to each of the top 100 industrial chemicals.
