Production of ethanol from winter barley by the EDGE (enhanced dry grind enzymatic) process

<p>Abstract</p> <p>Background</p> <p>US legislation requires the use of advanced biofuels to be made from non-food feedstocks. However, commercialization of lignocellulosic ethanol technology is more complex than expected and is therefore running behind schedule. This is creating a demand for non-food, but more easily converted, starch-based feedstocks other than corn that can fill the gap until the second generation technologies are commercially viable. Winter barley is such a feedstock but its mash has very high viscosity due to its high content of β-glucans. This fact, along with a lower starch content than corn, makes ethanol production at the commercial scale a real challenge.</p> <p>Results</p> <p>A new fermentation process for ethanol production from Thoroughbred, a winter barley variety with a high starch content, was developed. The new process was designated the EDGE (enhanced dry grind enzymatic) process. In this process, in addition to the normal starch-converting enzymes, two accessory enzymes were used to solve the β-glucan problem. First, β-glucanases were used to hydrolyze the β-glucans to oligomeric fractions, thus significantly reducing the viscosity to allow good mixing for the distribution of the yeast and nutrients. Next, β-glucosidase was used to complete the β-glucan hydrolysis and to generate glucose, which was subsequently fermented in order to produce additional ethanol. While β-glucanases have been previously used to improve barley ethanol production by lowering viscosity, this is the first full report on the benefits of adding β-glucosidases to increase the ethanol yield.</p> <p>Conclusions</p> <p>In the EDGE process, 30% of total dry solids could be used to produce 15% v/v ethanol. Under optimum conditions an ethanol yield of 402 L/MT (dry basis) or 2.17 gallons/53 lb bushel of barley with 15% moisture was achieved. The distillers dried grains with solubles (DDGS) co-product had extremely low β-glucan (below 0.2%) making it suitable for use in both ruminant and mono-gastric animal feeds.</p

GraphMineSuite: Enabling High-Performance and Programmable Graph Mining Algorithms with Set Algebra

We propose GraphMineSuite (GMS): the first benchmarking suite for graph mining that facilitates evaluating and constructing high-performance graph mining algorithms. First, GMS comes with a benchmark specification based on extensive literature review, prescribing representative problems, algorithms, and datasets. Second, GMS offers a carefully designed software platform for seamless testing of different fine-grained elements of graph mining algorithms, such as graph representations or algorithm subroutines. The platform includes parallel implementations of more than 40 considered baselines, and it facilitates developing complex and fast mining algorithms. High modularity is possible by harnessing set algebra operations such as set intersection and difference, which enables breaking complex graph mining algorithms into simple building blocks that can be separately experimented with. GMS is supported with a broad concurrency analysis for portability in performance insights, and a novel performance metric to assess the throughput of graph mining algorithms, enabling more insightful evaluation. As use cases, we harness GMS to rapidly redesign and accelerate state-of-the-art baselines of core graph mining problems: degeneracy reordering (by up to >2x), maximal clique listing (by up to >9x), k-clique listing (by 1.1x), and subgraph isomorphism (by up to 2.5x), also obtaining better theoretical performance bounds

ENZYMATISCHE MODIFIZIERUNG VON ENZYMEN GLUCOAMYLASE ALS BEISPIEL AUS DER STÄRKEVERARBEITUNG

The chemical modification of microbial enzymes has gained increased importance. A controlled enzymatic treatment of biocatalysts can be another step towards "taylor-made" enzymes for use in food industry. The transformation of starch containing raw materials in maltose, glucose and fructose are established processes. Anyhow, it will be shown in this presentation, how a specific modification of ASPERGILLUS NIGER-Glucoamylases can lead to interesting properties in the application of industrial saccharification. During the late stage of the submerse production of glucoamylase from ASPERGILLUS NIGER, a proteolytic modification of the enzyme molecule happens. The formed enzyme shows a slightly different substrate specificity than the original enzyme. The properties of the purified glucoamylase- isoenzymes are demonstrated by means of degradation trials with branched and linear oligosaccharides. Isomaltose is formed as the main product of the reverse action from glucose as substrate by both isoenzymes. Both glucoamylases are able to split alpha-1-6-glucosidic bonds of maltooligosaccharides. The practical importance and possible influences of a certain isoenzyme ratio of commercial glucoamylases are explained with comparative saccharification trials using enzymatically liquefied wheat starch as substrate