The effect of temperature on a very high gravity ethanol fermentation using no cook process was investigated. We found that a gradient temperature control strategy could improve the fermentation efficiency significantly, With the assistance of a new raw starch hydrolyzing enzyme and a gradient temperature control strategy, the ethanol concentration could reach up to 20% (V/V) within 90 h using commercially available dry yeast, when sorghum was used as the raw material and the dry substrate concentration was controlled at 35%.
Enzymes ; metabolism ; Ethanol ; analysis ; metabolism ; Fermentation ; Hydrolysis ; Seeds ; metabolism ; Sorghum ; metabolism ; Temperature ; Yeasts ; metabolism

In order to explore the feasibility of planting sweet sorghum in sugarcane growing area to prolong milling duration for bioethanol production, 15 varieties were sown monthly from March to September in Liuzhou of Central Guangxi Zhuang Autonomous Region. Yields of fresh stem, grain and leave were documented. The results showed that all varieties grew well when sown from March to August, but could not get mature when sown after late September. The high fresh stem yields were observed for the varieties Sart and PT3-S, 79.28 t/hm2 and 78.58 t/hm2 for single growing season, and 157.95 t/hm2 and 155.25 t/hm2 for two growing seasons. Ripening began from the end of June to late December, making the feed stock available for ethanol production from July to the end of December, even January next year.
Agriculture ; methods ; China ; Ethanol ; metabolism ; Feasibility Studies ; Plant Stems ; metabolism ; Saccharum ; growth & development ; metabolism ; Seasons ; Sorghum ; growth & development ; metabolism

A robust strain of the species Saccharomyces cerevisiae CGMCC1949 was screened and identified, and advanced solid state fermentation (ASSF) technology for fuel ethanol production from sweet sorghum stalks was thus developed. The fermentation time was shortened to less than 30 h, and ethanol yield was 92% of its theoretical maximum. And in the meantime, the cost-effective storage was established for sweet sorghum stalks, with less than 5% sugar loss after 200 days of storage, making the plant operation could extend up to 200 days without feedstock shortage. With the fermentation kinetics and heat-mass transfer models, modeling of the ASSF process was investigated, and the rotating drum bioreactor was designed. Furthermore, the ASSF technology was successfully applied in the pilot plant in which the rotating drum bioreactor was scaled up to 127 m3, and ethanol yield of 91% was achieved. At the end, techno-economic analysis (TEA) conducted by ASPEN indicated that ethanol production from sweet sorghum stalks by the ASSF is economically competitive.
Bioreactors ; microbiology ; Ethanol ; metabolism ; Fermentation ; Industrial Microbiology ; methods ; Models, Theoretical ; Plant Stems ; metabolism ; Saccharomyces cerevisiae ; metabolism ; Sorghum ; metabolism

Nitrate is the main form of inorganic nitrogen that crop absorbs, and nitrate transporter 2 (NRT2) is a high affinity transporter using nitrate as a specific substrate. When the available nitrate is limited, the high affinity transport systems are activated and play an important role in the process of nitrate absorption and transport. Most NRT2 cannot transport nitrates alone and require the assistance of a helper protein belonging to nitrate assimilation related family (NAR2) to complete the absorption or transport of nitrates. Crop nitrogen utilization efficiency is affected by environmental conditions, and there are differences between varieties, so it is of great significance to develop varieties with high nitrogen utilization efficiency. Sorghum bicolor has high stress tolerance and is more efficient in soil nitrogen uptake and utilization. The S. bicolor genome database was scanned to systematically analyze the gene structure, chromosomal localization, physicochemical properties, secondary structure and transmembrane domain, signal peptide and subcellular localization, promoter region cis-acting elements, phylogenetic evolution, single nucleotide polymorphism (SNP) recognition and annotation, and selection pressure of the gene family members. Through bioinformatics analysis, 5 NRT2 gene members (designated as SbNRT2-1a, SbNRT2-1b, SbNRT2-2, SbNRT2-3, and SbNRT2-4) and 2 NAR2 gene members (designated as SbNRT3-1 and SbNRT3-2) were identified, the number of which was less than that of foxtail millet. SbNRT2/3 were distributed on 3 chromosomes, and could be divided into four subfamilies. The genetic structure of the same subfamilies was highly similar. The average value of SbNRT2/3 hydrophilicity was positive, indicating that they were all hydrophobic proteins, whereas α-helix and random coil accounted for more than 70% of the total secondary structure. Subcellular localization occurred on plasma membrane, where SbNRT2 proteins did not contain signal peptides, but SbNRT3 proteins contained signal peptides. Further analysis revealed that the number of transmembrane domains of the SbNRT2s family members was greater than 10, while that of the SbNRT3s were 2. There was a close collinearity between NRT2/3s of S. bicolor and Zea mays. Protein domains analysis showed the presence of MFS_1 and NAR2 protein domains, which supported executing high affinity nitrate transport. Phylogenetic tree analysis showed that SbNRT2/3 were more closely related to those of Z. mays and Setaria italic. Analysis of gene promoter cis-acting elements indicated that the promoter region of SbNRT2/3 had several plant hormones and stress response elements, which might respond to growth and environmental cues. Gene expression heat map showed that SbNRT2-3 and SbNRT3-1 were induced by nitrate in the root and stem, respectively, and SbNRT2-4 and SbNRT2-3 were induced by low nitrogen in the root and stem. Non-synonymous SNP variants were found in SbNRT2-4 and SbNRT2-1a. Selection pressure analysis showed that the SbNRT2/3 were subject to purification and selection during evolution. The expression of SbNRT2/3 gene and the effect of aphid infection were consistent with the expression analysis results of genes in different tissues, and SbNRT2-1b and SbNRT3-1 were significantly expressed in the roots of aphid lines 5-27sug, and the expression levels of SbNRT2-3, SbNRT2-4 and SbNRT3-2 were significantly reduced in sorghum aphid infested leaves. Overall, genome-wide identification, expression and DNA variation analysis of NRT2/3 gene family of Sorghum bicolor provided a basis for elucidating the high efficiency of sorghum in nitrogen utilization.
Nitrate Transporters ; Nitrates/metabolism* ; Sorghum/metabolism* ; Anion Transport Proteins/metabolism* ; Phylogeny ; Protein Sorting Signals/genetics* ; Nitrogen/metabolism* ; DNA ; Gene Expression Regulation, Plant ; Plant Proteins/metabolism*

Sorghum (Sorghum bicolor L.) was one of the most important crops in the world next to wheat, rice, maize, soybean and barley. Using the callus derived from immature inflorescence as the recipients, we efficiently transformed sorghum varieties 115, ICS21B and 5-27 with the insecticidal Bacillus thuringiensis (Bt) cry1Ab gene carried in the T-DNA of binary vectors which contained hygromycin resistance gene and gus gene via Agrobacterium tumefaciens. After gradient selection with hygromycin, a total of 21 independent transgenic plant lines, 52 transgenic plants were regenerated, and the average stably transformation efficiency was 1.9%. The integration and transcription of cry1Ab gene in transgenic sorghum was confirmed by PCR analysis, Southern blotting and RT-PCR analysis. The Bt proteins were expressed in most transgenic plants with different level from plant to plant by Western blotting and ELISA assay. According to insect bioassay in laboratory, the transgenic plants with a relatively high level of Bt gene expression displayed insect-resistance to pink rice borer (Sesamina inferens).
Agrobacterium tumefaciens ; genetics ; metabolism ; Bacterial Proteins ; genetics ; metabolism ; Endotoxins ; genetics ; metabolism ; Hemolysin Proteins ; genetics ; metabolism ; Pest Control, Biological ; Plants, Genetically Modified ; genetics ; Sorghum ; genetics ; Transformation, Genetic