Physico-chemical characterization of feedstocks and native plant biomass available in Mexico. Pre-treatment and fermentation of hydrolysates

Mexico has an increasingly large population, decreasing reserves of oil and fossil fuels, and very limited land area suitable for agriculture.  A large scale nation-wide project is leaded by the Mexican Petroleum Institute, the National Polytechnic Institute, and the National Institute for Research in Agro-Forestry and Animal Production.  Twenty-four different plant materials, feed stocks and native plants biomass samples, which include dedicated agricultural feedstocks, agro-industrial and forestry by-products, as well as previously uncharacterized wild native plant biomass, were all characterized by physical and chemical methods. Their content of lignin, cellulose and hemicellulose was determined. The materials were treated by either strong thermo-acid, or enzymatic processes to achieve total hydrolysis.  The reducing sugars yield was determined by spectrophotometric methods, while both monosaccharide composition and potential fermentation inhibitors in the hydrolysates, were determined by HPLC with either refractive index or diode array detectors. Hydrolysates were then fermented using two different commercial yeast cultures available in Mexico, and the alcohol yield determined by YSI and HPLC. Based on the sustainability of their production, their stability and quality as raw materials, as well as their potential for bioconversion, 8 different biomaterials were selected for further studies. Among the selected materials, introduced grasses, agave biomass and agroindustrial by-products of large abundance are considered for large scale processing, for the production of bioethanol and chemicals.