1.) Solving the biomass recalcitrance challenge: impacts go beyond 2012
The talk, by Dr. Himmel, was on the subject of the rigidity and protective qualities of the cell wall, and how this makes permeability more difficult to achieve. Plants have adapted a rigid cell wall to protect itself from the outside world, such as microbes. Due to this increase in protection, the break down of the cell well is extremely difficult. Dr. Himmel’s research has showed that pretreatment significantly increases the permeability of the cell wall. Increased acid treatment is not cost effective enough to consistently use, causing for new research to develop other effective ways, which has led to the Steam Gun method. The pretreatment method of Steam Gun has shown to be more effective, without the negative effects of changing the xylan content, and it lowers the severity of acid treatment. However, to effectively manipulate the cell wall, more needs to be known about it. Current research is using fungal cellulase markers to tag the areas where break down occurs.
2.) What are the key substrate factors which limit the hydrolysis of biomass by cellulases?
This talk, presented by a postdoc from the University of British Columbia, was about lignocellulosic biomass being heterogeneous and how this affected pretreatment choice. There were several groups of types of lignocellulosic biomass, including hardwoods and softwoods. Pretreatment choices was determined by the type of lignocellulosic biomass, like hardwoods required steam and dilute acid, while softwoods required a different pretreatment from that, organosolv and pulping. The focus for this research team was on bioconversion of lignocellulose from trees, learning about how the treatments affect the lignocellulose. The goal of the research was to make pretreatments more homogeneous, which would make pretreatments more cost effective.
3.) The significance of supramolecular structures of cellulose for the enzymatic hydrolysis of plant cell walls
This was a talk about differences in the supramolecular structures of cellulose that can be altered by enzymatic hydrolysis, affecting the plant cell wall. In cellulose fibers there are regions called dislocations, which are regions of different organization and structure in the cellulose, which are susceptible to various forms of degradation. These regions have in the past been assumed to be amorphous, however, this research team attempted to prove that they are in fact birefringent, thus they have a crystalline organization, but the exact structure remains unknown. Results from this study show that dislocations are important during the initial part of enzymatic hydrolysis of cellulose.
4.) Genetic dissection of bioenergy traits in sorghum
According to this research team, Sorghum, a plant species related to corn and sugar cane, has a number of characteristics that make it a very attractive biomass crop for ethanol production: low water and fertilizer requirements, tolerance to heat and drought, high biomass yield, and great genetic diversity. Two traits of particular interest to this research team are the sweet sorghum trait, which results in the accumulation of fermentable sugars in the juice of the stems, and the brown midrib (bmr) trait, which changes the color and the chemical composition of the vascular tissue, and results in higher yields of fermentable sugars obtained after enzymatic processing of the lignocellulosic biomass. The genetic basis of these traits, however, is poorly understood and impedes the full exploitation of sorghum for bioenergy production.
5.) Fundamental Knowledge for sustainable cellulosic biofuels
This was a talk given by Great lakes Bioenergy Partners, who work in conjunction with 6 primary academic groups, mainly Wisconsin and Michigan State University. Their current research is focused on improving plants for use of cellulosic biofuels, improving pretreatments and enzymes in order to generate low-cost cellulosic sugar streams, and improving the sustainability of cellulosic biofuel cropping systems. One major focus of this group was improving the sustainable biofuel production, which the believed they could do by improving cellulosic biofuel cropping systems. They planned to track energy inputs and plant microbial outputs from different cropping systems. In conclusion, they hope to improve the sustainability of the cellulosic biofuels enterprise.