Bioethanol Production From High Sugary Corn Genotypes by Decreasing Enzyme Consumption

This is a PhD proposal defended in a 2012-2013 session at the Institute of Biological Sciences, Faculty of Science, University of Malaya, Malaysia. The proposal has been written in accordance with the requirements of the university under the sub-headings: background, problem statement, rationale, hypothesis and research questions, research objectives, literature review, methodology, scope, expected outcomes and concluding remarks, work schedule, and references. This proposal provides a comprehensive study on bioethanol production from corn. First, it discusses development and field experiments of high sugary genotypes (HSGs). Secondly, it provides a comparative evaluation of enzyme consumptions and ethanol production between normal and HSG corn genotypes. Finally, this proposal provides evaluation of the co-product quality for both groups of genotypes. The readers who are interested to conduct any further study on corn-based bioethanol would be benefited from this proposal.

Impact of the D genome and quantitative trait loci on quantitative traits in a spring durum by spring bread wheat cross

The impact of the D genome and QTL in the A and B genomes on agronomic performance of hexaploid wheat and tetraploid durum was determined using novel recombinant inbred line populations derived from interploid crosses. Genetic differences between common hexaploid (6X) bread wheat (Triticum aestivum, 2n = 6x = 42, genome, AABBDD) and tetraploid (4X) durum wheat (T. turgidum subsp. durum, 2n = 4x = 28, genome, AABB) may exist due to effects of the D genome and allelic differences at loci in the A and B genomes. Previous work allowed identification of a 6X by 4X cross combination that resulted in a large number of fertile recombinant progeny at both ploidy levels. In this study, interspecific recombinant inbred line populations at both 4X and 6X ploidy with 88 and 117 individuals, respectively, were developed from a cross between Choteau spring wheat (6X) and Mountrail durum wheat (4X). The presence of the D genome in the 6X population resulted in increased yield, tiller number, kernel weight, and kernel size, as well as a decrease in stem solidness, test weight and seed per spike. Similar results were found with a second RIL population containing 152 lines from 18 additional 6X by 4X crosses. Several QTL for agronomic and quality traits were identified in both the 4X and 6X populations. Although negatively impacted by the lack of the D genome, kernel weight in Mountrail (4X) was higher than Choteau (6X) due to positive alleles from Mountrail on chromosomes 3B and 7A. These and other favorable alleles may be useful for introgression between ploidy levels.

A laboratory protocol for determining glucose and maximum ethanol production from wheat grain: application to a complete genetic set of near-isogenic waxy lines

A laboratory protocol was developed to assess glucose and ethanol yields from wheat. The impact of the analyzed wholemeal flour quantity and the saccharification on the amount of released glucose was estimated. The whole process including the analytical methods (glucose and ethanol) was repeatable and reproducible. This protocol was used to assess the glucose and ethanol yields of six varieties and of a complete set of hexaploid near-isogenic waxy lines of cv. Trémie grown in three locations. As compared to the normal line of Trémie, double null (AnBnD) and triple null (nAnBnD) isogenic lines showed a low Hagberg falling number (218, 65, and 63 s, respectively), a higher grain protein content (10.7, 11.5, and 12.1% DM, respectively), a lower glucose yield (728, 703, and 707 kg/t, respectively), and a lower ethanol yield (463, 453, and 452 L/t, respectively). These values indicate a strong involvement of alleles encoded at Wx-B1 and Wx-D1 loci in grain composition.

Factors affecting usefulness of triticale grain for bioethanol production

BACKGROUND

Triticale grain could be a useful material for bioethanol production. The aim of this study was to examine how grain cultivar, nitrogen fertilisation level, location and year affect the starch content in triticale grain and which method of starch determination, polarimetric, enzymatic or near-infrared transmission (NIT), gives the best prediction of real bioethanol productivity from triticale grain.

RESULTS

It was found that the starch content in triticale grain was correlated positively with test weight and 1000-kernel weight but negatively with falling number and protein content. All factors, i.e. cultivar, nitrogen fertilisation level, location and year, as well as the intrinsic interaction between these factors, had a significant effect on the starch level in triticale grain. The NIT procedure of starch determination gave the best results in predicting the real yield of ethanol obtained on the basis of classic fermentation (95% match), while the enzymatic and polarimetric methods corresponded with the real results at levels of 89-90 and 78-82% respectively.

CONCLUSION

Grain growth conditions related to location and nitrogen fertilisation level had the most noticeable effect on grain starch content, while grain yield per hectare had the most significant effect on ethanol productivity.

Characterisation of fermentation of high-gravity maize mashes with the application of pullulanase, proteolytic enzymes and enzymes degrading non-starch polysaccharides

The aim of the research was to assess the possibility of the fermentation productivity rising through the increase in corn mashes extract from 16-17 to 20-21 degrees Balling, yet keeping a 3-day fermentation period. The second goal was to obtain the highest possible utilization of starch in the raw material through deep enzymatic degradation and utilization of available sugars and simultaneous maintenance of high quality spirit. It was found that fulfilling the above during the 3-day fermentation period was possible with the application of pullulanase as an additional amylolytic enzyme. Adding pullulanase resulted in the acceleration of the starch hydrolysis degree, which led to lower amounts of unhydrolyzed dextrins and higher ethanol yield. When the supportive enzymes complex (pullulanase, protease and cellulase) was used, the final ethanol concentration reached 10.86+/-0.04% v/v, with ethanol yield at 68.41+/-0.23 dm(3) of absolute ethanol (A(100)) per 100 kg of starch, which was 95.25+/-0.32% at the theoretical value. The acceleration of starch enzymatic degradation and the application of a proteolytic preparation visibly shortened both initial and main fermentation phases. This in turn increased the time of the final fermentation phase and resulted in more extensive utilization of substrates by yeasts with simultaneous reduction of the final concentration of acetaldehyde (26.0+/-0.5 mg/dm(3)A(100)) and diethyl acetal of acetaldehyde (2.5+/-0.5 mg/dm(3)A(100)). The quality of spirit obtained was positively verified also in terms of relatively low concentration of higher alcohol (3912.2+/-9.8 mg/dm(3)A(100)). Preliminary analysis of costs (without raw-material) of 1 l distillate production indicated the possibility to reduce the costs by 18-20%.