Hector Hernandez Escoto
Department of Chemical Engineering
University of Guanajuato
Hector Hernandez Escoto completed his PhD at the age of 29 years from Universidad Autonoma Metropolitana – Iztapalapa (México) in the field of process control. He has followed this research line, applying and developing corresponding tools for the process design and control of systems of stirred tank reactors, firstly working during 4 years for COMEX Research Center (México), and next in the University of Guanajuato, where is titular professor. He has published more than 10 papers in reputed journals, has directed and been implied in 5 industrial projects, and is member of the Researchers National System of México.
A main question for designing a saccharification process of lignocellulosic material is determining in which conditions the enzymatic complex to be used will be effective. Commercial enzymatic cocktails are provided with conditions that span certain values. Due to complexity of the system enzymatic cocktail - lignocelluosic biomass, process conditions are not the same for every lignocellulosic mass; then, a scan of process conditions has to be carried out, many times following a response surface methodology. In this work, we addressed the scan of process conditions through an economic system to carry out numerous experiments: a thermomixer where Eppendorf® tubes are considered as micro-reactors. Then, the determination of effective process conditions for a certain commercial enzymatic cocktail (of unknown exact content of enzymes) to hydrolyze wheat straw, and how the process conditions change with different substrates are described. Alkali- and dilute- acid pretreated wheat straw, and pure cellulose were substrates while enzymatic complex (Accellerase 1500) was kindly provided by Genencor. The factors that the micro-reaction system allowed to study were temperature, pH and dosage of enzyme. Every micro-reactor was filled with the same amount of holocellulosic material; thermochemical pretreated straw (alkali and acid) was milled to pass through a sieve No. 40. Glucose and xylose were measured by a YSI biochemical analyzer, and reducing sugars were determined with DNS method. Response surfaces were constructed for each substrate, allowing, in addition to the display of best process conditions, an economic and fast comparison of pretreatments: alkaline pretreatment allowed the obtaining of higher concentrations of sugar.