The 32nd Symposium on Biotechnology for Fuels and Chemicals was underway with an alarming statistic estimating that by 2020, 80% of petroleum reserves will reside in the Middle East and North Africa. The following speaker subsequently discussed that agricultural ability is far more balanced, explaining the need for biofuels and thus our presence at the conference. The United States Department of Energy has three different technology investment pathways for renewable fuels: basic science driven (understanding structural biology and enzyme engineering), technology driven (end-product attenuation and pretreatment reactors), and industry driven. Biomass Recalcitrance, the inherent tendency of a plant cell wall structure to hinder its breakdown into sugars, is perhaps the greatest issue facing the use of lignocellulosic biomass for biofuels. He described that the three main issues associated with this are physical access, chemical access due to thermodynamic barriers, and the plants intrinsic resistance to depolymerization. The end portion of his discussion dealt with the effect of particle size on enzyme digestibility. His research showed that particle size decreases w/ increases severity, and enzyme digestibility increases w/ decreasing particle size; this was shown by using wet sieving to separate PCS into size fractions. An interesting fact that he also found in his study was that delamination was an unintended results of pretreatment; delamination is a form of failure for composite materials. Essentially, treated cell wall is more accessible but new structures form and new aggregations of microfibrils appear. Also increased ordering in macrofibril w also indicated by Raman spectropscopy; this technique analyzes vibrational, rotational, and other low-frequency modes in a system. He concluded by articulated that new solutions to biomasss recalcitrance are more science and better tools and technological approaches.
Another speaker also spoke on a similar issue saying that, “to understand how to take something apart, we must understand how to put it together.” His lecture focused around five levels of structure that must be considered to fully understand the bioconversion of lignocellulose from trees of various types (compression wood, tension wood, and early wood). He explained that lignocellulosic biomass is quite heterogenous and this affects the pretreatment choice. For example, hardwoods require steam and dilute acid while softwoods utilize other pretreatment mechanisms. He believes the ideal pretreatment provides recovery of hemicellulose and lignin in a high value form and also maximizes the accessibility of cellulose to enzymes. Furthermore, he established that efficient cellulose hydrolysis requires high surface area. Althought new to me, he spoke extensively on a process called hornification, a technical term often used to describe changes in fibers affected by drying or recycling. His research found that Hornification decreases hydrolysis yields and has significant effects on cellulose accessibility upon re-wetting. He concluded his talk with a take home message articulating that the world needs cheaper pretreatments that can effectively overcome heterogeneity.
Today’s speaker initiated their lecture with a simple, yet direct, quote. He said, “we need to use less to produce more from less.” According to him, we have currently used 33% of Earth’s surface for fuel, but this is 55% of the habitable land if take out places like Antarctica. He also explained the shift of who is growing crops—sovereign nations are going into developing countries and renting land, countries like South Korea, China, and UAE are leaders here. Furthermore, there is also a global water scarcity where water is available; the most extreme is in northern Africa and Australia, but this scarcity is often seasonal. Remembering that by 2050 there will be 9 billion people, freshwater implications of land use include maintaining stream flows, freshwater quality, and downstream habitat impacts. Various policies have been implemented for end use such as Renewable Fuel Standards by the EPA, renewable energy directive, and low carbon fuel standards. Policies and laws for resource use are quote numerous—Brazil has sugarcane and land-zoning laws, South Africa has a stream flow reduction tax, Australia has a freshwater risk abatement, and Tanzania has limits on biofuel production.
One woman of Italian descent spoke about the Inter-American Development Bank’s (IDB) efforts in promoting sustainable biofuels. She began by explaining how the IDB contribution to solving energy issues entails a biofuels sustainability scorecard, biofuels action plans and technical cooperation, and implementation of biofuels standards and certification schemes. One man asked why they used a scorecard and she replied that there was a high demand for IDB support in biofuels development so they needed a way to pre-screen the best projects. Creation of this scorecard was done by partnership with the Roundtable on Sustainable Biofuels. They also had internal and external feedback from academics, NGO’s, investors, and financial institutions in the US, EU, and in LAC. The scorecard was laughed in 2008 and quite interestingly, is an instrument to the bank but is still readily available to the public (www.iadb.org/biofuelsscorecard). To this end, d the Biofuels Sustainability Scorecard includes key sustainability criteria to incentive more sustainable practices in biofuels projects. Essentially, this tool has equipped the IDB and its clients with cutting-edge applied knowledge designed to strengthen the development effectiveness of interventions in the region.
One talk titled Fundamental knowledge for sustainable cellulosic biofuels was an informative talk that discussed the core information needed to understand cellulosic biofuels. Clearly, the aim with this type of research is to improve plants for use as cellulosic biofuels feedstocks, improve knowledge to improve pretreatments and enzymes in order to generate low-cost cellulosic sugar streams, and also to improve conversion of cellulosic sugar streams into ethanol and next generation biofuels and improve sustainability of biofuel cropping systems. He spent the majority of his session explaining a few issues and his approaches to them. First, he described how it is hard to generate fuel from cell wall sugars (due to recalcitrance) so one must modify hemicellulose. To understand how to do this they dissected xylan polymer synthesis by transcript profiling of xylose or mannose rich seedlings. They then sequenced RNA EST libraries to identify the candidate genes and then test/confirm function by inactivating candidate genes. A second issue that he mentioned was the notion that sugar release requires pretreatment. For example, he explains that untreated corn stover can be transformed to HMF or sugars in a one step release; this is fermentable by ecoli in yeast. He subsequently explained how improving microbes for fuel production is done by anaerobic growth. They produce sugar transporters and enzymes to make building blocks and fuels; his laboratory did this in various E.coli strains. By doing this, they can improve refinery microbes by combining the positive traits that they find. He concludes by articulating that improving sustainable biofuel production is done by tracking energy inputs, measuring soil, carbon, water and GHG effects, quantifying pests and diseases in ecosystems, and establishing life cycle models testing various biophysical land use and marketplace responses.