Christoph Emmerling is Associate Professor of Soil Science at the Soil Science Department, Faculty of Regional and Environmental Sciences, University of Trier. His main emphases in research and teaching are Soil Biology, Land-use Change, and Renewable Resources. From 2001 until 2005 he was head of the commission Soil Biology of the Soil Science Society of Germany. Recently he is member of TriCSS – Trier Centre of Sustainable Studies – and of the steering committee Bioenergy 2.0 of Rhineland-Palatinate, Germany.
The ecological drawbacks of growing maize like soil erosion and the use of large quantities of fertilizers and biocides effected the debate about its use as biogas substrate. Consequently, the investigation of alternative plants for this purpose is subject of many research activities. An auspicious approach is the use of perennial energy crops. The cultivation of such species is associated with ecological (soil protection, biodiversity, no use of biocides) and economical (no sowing and plant protection after establishment, avoidance of work peaks) advantages. In the light of doubts and reservations against new biogas substrates, our approach is to substitute only parts of maize in the biogas feedstock. With growing acceptance, the shares can be raised up to total substitution. In this context, the compability of both substrates is very important. Inhibitional effects that decrease the methane yield of both maize and the alternative energy crop should be avoided. Furthermore, a neutral behaviour of this composites or even better synergetic effects (e.g. compensation of nutrient deficiencies) should be achieved. To investigate the interaction with maize we mixed it with different shares (0, 10, 25, 50, 75, 100 %) of diverse alternative energy crops (Miscanthus giganteus, Sida hermaphrodita, Silphium perfoliatum, Elymus elongatus as cultivated variety “Szarvasi”) and incubated them for 50 days in a batch assay. The biochemical methane potential of these composites was then compared with the theoretical sum of the respective proportion of separately digested substrates to detect interactive effects.
In Taek Hwang has completed his PhD from Chonbuk National University in Korea and postdoctoral studies from Virginia Poly-tech. Institute and State University. He has been a principal research scientist at Korea Research Institute of Chemical Technology (KRICT) since 2000 and Research Fellow in 2013. He has been an adjunct professor of the department of Green Chemistry & Environmental Biotechnology, University of Science & Technology (UST) in Korea since 2010. His current research work is focused on the biochemical conversion in the biorefinery process, especially, discovery of enzymes and chemo-enzymatic bio-catalysis. He has published more than 30 papers in reputed journals and has been teaching studients as an professor of UST.
A new methodology for the total cellulose hydrolysis using a chemo-enzymatic system of combining chemical depolymerization process and enzymatic hydrolysis was described in this paper. The approach undertaken herein involves the dissolution of cellulose in an ionic liquid (IL), depolymerization by acidic solid catalyst, and obtained total cello-oligomers aided by antisolvent. The yield of soluble cello-oligomers from cellulose depolymerization was 81.1% under 81.3% conversion and recovery of 99.8% treated with 1.5% AMB at 100oC for 1 h. Followed by the chemical depolymerization, all of the total soluble cellooligomers which are longer as in molecular length than cello-biose extracted from the reaction mixture was virtually hydrolyzed to the glucose by the β-1,4-D-glucan glucohydrolase identified from a Paenibacillus sp. HPL-001, which is different to other commercialized β-1,4-D-glucosidase. Continuous recycling 99% of ionic acid and organic solvent completely breaks down the cellulose to soluble sugars shorter than 6 AGU cellooligomers. The efficiency of this technology could compromise the dissolution and selective deconstruction problem for a crucial step in the production of glucose as final product without further degradation from cellulose as an alternative techno-economic process against traditional expensive three-enzymatic hydrolysis.