Deep Eutectic Solvent Pretreatment of Transgenic Biomass With Increased C6C1 Lignin Monomers.

The complex and heterogeneous polyphenolic structure of lignin confers recalcitrance to plant cell walls and challenges biomass processing for agroindustrial applications. Recently, significant efforts have been made to alter lignin composition to overcome its inherent intractability. In this work, to overcome technical difficulties related to biomass recalcitrance, we report an integrated strategy combining biomass genetic engineering with a pretreatment using a bio-derived deep eutectic solvent (DES). In particular, we employed biomass from an Arabidopsis line that expressed a bacterial hydroxycinnamoyl-CoA hydratase-lyase (HCHL) in lignifying tissues, which results in the accumulation of unusual C6C1 lignin monomers and a slight decrease in lignin molecular weight. The transgenic biomass was pretreated with renewable DES that can be synthesized from lignin-derived phenols. Biomass from the HCHL plant line containing C6C1 monomers showed increased pretreatment efficiency and released more fermentable sugars up to 34% compared to WT biomass. The enhanced biomass saccharification of the HCHL line is likely due to a reduction of lignin recalcitrance caused by the overproduction of C6C1 aromatics that act as degree of polymerization (DP) reducers and higher chemical reactivity of lignin structures with such C6C1 aromatics. Overall, our findings demonstrate that strategic plant genetic engineering, along with renewable DES pretreatment, could enable the development of sustainable biorefinery

Influence of Oxygen Microenvironment on Microfluidic Glucose Sensor Performance

We propose a novel method to overcome significant problems of baseline drift and sensitivity degradation in amperometric biosensors based on oxidase enzyme reactions. A novel glucose microsensor with a built-in electrochemical oxygen manipulation microsystem is introduced to demonstrate three novel functionalities; one-point in situ self-calibration (zero-point), broadening of dynamic range and increase in sensitivity. The influence of electrochemically generated oxygen microenvironment on the sensor output within a fluidic structure is investigated

Electrochemical and Hydrodynamic Interferences on the Performance of an Oxygen Microsensor with Built-in Electrochemical Microactuator

An in situ self-diagnostic technique for a dissolved oxygen microsensor is proposed in an effort to devise an intelligent microsensor system with an integrated electro-chemical actuation electrode. With a built-in platinum microelectrode that surrounds the microsensor, two kinds of microenvironments (oxygen-saturated or oxygen-depleted phases) can be created by water electrolysis depending on the polarity. The functionality of the microsensor can be checked during these microenvironment phases. The polarographic oxygen microsensor is fabricated on a flexible polyimide substrate (Kapton/sup ©/) and the influences of electrochemical and hydrodynamic conditions on the sensor responses have been investigated

Work in Progress -- Balancing Prescribed and Project-Based Experiences in Microfabrication Laboratories

Student education for microfabrication processes needs to integrate theoretical understanding with process understanding. Instructional challenges exist in designing effective laboratory experiences. The pedagogical issues include linking theoretical lecture concepts to cost-effective laboratories, tailoring the relative time between lectures and laboratories, and balancing the laboratory assignments between prescribed and project-based experiences. We describe the progressive implementations of microfabrication laboratory experiences in graduate courses. The first offering has no laboratory activity. The prescribed laboratory and project-based laboratory components were gradually incorporated. All laboratory experiences were team-based and utilized cost-effective facilities. The assessments indicate that students prefer significant laboratory experience and that learning of selected lecture concepts is enhanced through an interactive environment. Furthermore, observations are made concerning the effective balance of lecture and laboratories and of prescribed and project-based experiences