Energy analysis of ethanol production from sweet sorghum

The Piedmont System is a collection of equipment for efficiently removing the juice from sweet sorghum stalks for the production of ethanol. The concept is to separate the whole stalks into pith and rind-leaf fractions, pass only the pith fraction through a screw press, and thus achieve an improvement in juice-expression efficiency and press capacity. An energy analysis was done for two options of this proposed harvesting/processing system: (Option 1) The juice is evaporated to syrup and used throughout the year to produce ethanol, and the by-products are used as cattle feed. (Option 2) The juice is fermented as it is harvested, and the by-products (along with other cellulosic materials) are used as feedstock for the remainder of the year. Energy ratios (energy output/energy input) of 0·9, 1·1 and 0·8 were found for sweet sorghum Option 1, sweet sorghum Option 2, and corn, respectively, as feedstocks for ethanol. If only liquid fuels are considered, the ratios are increased to 3·5, 7·9 and 4·5.     

先进固体发酵技术(ASSF)生产甜高粱乙醇

介绍了利用高产能源作物甜高粱生产燃料乙醇的先进固态发酵(ASSF)技术,从甜高粱茎秆保存、菌种、反应器,到固体发酵过程的数学模拟和工程放大进行了系统研究。筛选出高效产乙醇的菌种CGMCC1949,固体发酵时间低于30 h,乙醇收率高于92%;优选出贮存甜高粱茎秆的有效方法,通过抑菌处理,厌氧贮存200 d糖分损失小于5%;对固态发酵过程进行了数学模拟,设计并优化了固体发酵设备,成功进行了工程放大试验,并且基于ASPEN软件对该技术进行了技术经济评价,结果表明ASSF法生产甜高粱乙醇在技术、工程和经济上均具有充分的可行性和明显优势。     

中国能源作物甜高粱的空间适宜分布及乙醇生产潜力

甜高粱作为能源作物在世界范围内广受关注,但目前对于甜高粱的空间分布及乙醇生产潜力尚缺乏专门的定量研究。依据气候、土壤、地形和土地利用等空间数据以及相关文献资料,探讨了甜高粱在中国的空间适宜分布。研究表明,我国大部分区域均可种植甜高粱;其中可种植的未利用地面积达5919.2×104hm2,主要集中于新疆和内蒙古等省区;而最适宜甜高粱种植的未利用地面积为286.7×104hm2,主要分布在黑龙江、内蒙古、山东和吉林等地。中国未利用地甜高粱乙醇生产潜力较大,在不考虑其它社会经济限制因素下,总乙醇生产潜力可达11838.5×104t以上。最适宜未利用地的甜高粱乙醇生产潜力为573.4×104-2637.8×104t,平均为1075.2×104t,可满足中国目前E20乙醇汽油84.8%的需求。如在适宜性较差和较适宜的未利用地种植甜高粱,应充分考虑开发成本和能源投入等问题。     

Ethanol production from sweet sorghum juice using very high gravity technology: Effects of carbon and nitrogen supplementations

Ethanol production from sweet sorghum juice by Saccharomyces cerevisiae NP01 was investigated under very high gravity (VHG) fermentation and various carbon adjuncts and nitrogen sources. When sucrose was used as an adjunct, the sweet sorghum juice containing total sugar of 280 g l⁻¹, 3 g yeast extract l⁻¹ and 5 g peptone l⁻¹ gave the maximum ethanol production efficiency with concentration, productivity and yield of 120.68 ± 0.54 g l⁻¹, 2.01 ± 0.01 g l⁻¹ h⁻¹ and 0.51 ± 0.00 g g⁻¹, respectively. When sugarcane molasses was used as an adjunct, the juice under the same conditions gave the maximum ethanol concentration, productivity and yield with the values of 109.34 ± 0.78 g l⁻¹, 1.52 ± 0.01 g l⁻¹ h⁻¹ and 0.45 ± 0.01 g g⁻¹, respectively. In addition, ammonium sulphate was not suitable for use as a nitrogen supplement in the sweet sorghum juice for ethanol production since it caused the reduction in ethanol concentration and yield for approximately 14% when compared to those of the unsupplemented juices.     

Butanol production from sweet sorghum bagasse with high solids content: Part I—comparison of liquid hot water pretreatment with dilute sulfuric acid

In these studies, we pretreated sweet sorghum bagasse (SSB) using liquid hot water (LHW) or dilute H₂SO₄ (2 g L^?1) at 190°C for zero min (as soon as temperature reached 190°C, cooling was started) to reduce generation of sugar degradation fermentation inhibiting products such as furfural and hydroxymethyl furfural (HMF). The solids loading were 250–300 g L^?1. This was followed by enzymatic hydrolysis. After hydrolysis, 89.0 g L^?1 sugars, 7.60 g L^?1 acetic acid, 0.33 g L^?1 furfural, and 0.07 g L^?1 HMF were released. This pretreatment and hydrolysis resulted in the release of 57.9% sugars. This was followed by second hydrolysis of the fibrous biomass which resulted in the release of 43.64 g L^?1 additional sugars, 2.40 g L^?1 acetic acid, zero g L^?1 furfural, and zero g L^?1 HMF. In both the hydrolyzates, 86.3% sugars present in SSB were released. Fermentation of the hydrolyzate I resulted in poor acetone‐butanol‐ethanol (ABE) fermentation. However, fermentation of the hydrolyzate II was successful and produced 13.43 g L^?1 ABE of which butanol was the main product. Use of 2 g L^?1 H₂SO₄ as a pretreatment medium followed by enzymatic hydrolysis resulted in the release of 100.6–93.8% (w/w) sugars from 250 to 300 g L^?1 SSB, respectively. LHW or dilute H₂SO₄ were used to economize production of cellulosic sugars from SSB. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:960–966, 2018     

Effects of three endophytic entomopathogens on sweet sorghum and on the larvae of the stalk borer Sesamia nonagrioides

Various endophytic fungi of native plants and crops are important entomopathogens. The objective of this study was to investigate the entomopathogenic action of Beauveria bassiana (Balsamo) Vuillemin, Metarhizium robertsii (Metchnikoff) Sorokin, and Isaria fumosorosea (Wize) Brown & Smith (all Ascomycota: Hypocreales) against larvae of Sesamia nonagrioides (Lefebvre) (Lepidoptera: Noctuidae) artificially introduced into Sorghum bicolor L. (Moench) (Poaceae) plants under natural environmental conditions. Sorghum bicolor is an economically important crop cultivated for grain, fiber, forage, and lately for biofuel, and S. nonagrioides is its main pest in Mediterranean areas. Young sorghum plants were inoculated with the entomopathogens by spraying in the field. Plant water status, chlorophyll concentration, photosynthesis, and transpiration were not affected. Thirty days after endophyte establishment, plants were infested with fourth instars of S. nonagrioides. The endophytes prevented 50–70% of larvae from entering stalks. Larval mortality was 70–100% and tunnel lengths were reduced by 60–87%. Larval infestation resulted in reduced electron transport capacity and net photosynthetic rate, which was ameliorated in the presence of I. fumosorosea and reversed by B. bassiana and M. robertsii. The growth of sorghum was unaffected in all treatments during the experimental period. Beauveria bassiana and M. robertsii can protect sweet sorghum from damage induced by S. nonagrioides under natural environmental conditions without affecting plant physiology and growth.     

Identification and comprehensive analysis of the CLV3/ESR‐related (CLE) gene family in Brassica napus L.

• The CLE (CLAVATA3/ESR) gene family, encoding a group of small secretory peptides, plays important roles in cell‐to‐cell communication, thereby controlling a broad spectrum of development processes. The CLE family has been systematically characterized in some plants, but not in Brassica napus.
• In the present study, 116 BnCLE genes were identified in the B. napus genome, including seven unannotated, six incorrectly predicted and five multi‐CLE domain‐encoding genes. These BnCLE members were separated into seven distinct groups based on phylogenetic analysis, which might facilitate the functional characterization of the peptides.
• Further characterization of CLE pre‐propeptides revealed 31 unique CLE peptides from 45 BnCLE genes, which may give rise to distinct roles of BnCLE and expansion of the gene family. The biological activity of these unique CLE dodecamer peptides was tested further through in vitro peptide assays. Variations in several important residues were identified as key contributors to the functional differentiation of BnCLE and expansion of the gene family in B. napus. Expression profile analysis helped to characterize possible functional redundancy and sub‐functionalization among the BnCLE members.
• This study presents a comprehensive overview of the CLE gene family in B. napus and provides a foundation for future evolutionary and functional studies.

     

Effect of harvest date and nitrogen fertilization rate on the nutritive value of amaranth forage (Amaranthus hypochondriacus)

This study was conducted to assess effects of harvest date (i.e., 40 and 60 d after planting) and N fertilization rate (i.e., 120, 180, 240 kg N/ha) on the nutritive value of amaranth forage (Amaranthus hypochondriacus) using a factorial experiment with a randomized complete block design. The content of dry matter (DM), crude protein (CP), true protein (TP), ether extract (EE), water soluble carbohydrates (WSC), ash-free neutral detergent fiber (NDFom), ash-free acid detergent fiber (ADFom), lignin(sa), ash, Ca, P, Na, K, oxalic acid and nitrate were determined. Soluble CP (SP) and protein fractions non-protein N (A), true protein rapidly degraded in the rumen (B₁), true protein degraded in the rumen at a moderate rate (B₂), true protein associated with the cell wall and slowly degraded in the rumen (B₃) and acid detergent insoluble CP (C) were measured according to the Cornell Net Carbohydrate and Protein System. In vitro gas production (IVGP), OM disappearance (OMD) and NDFom disappearance (NDFD) were determined using a gas production technique. Results showed that the later harvest date increased (P<0.05) DM, EE, WSC, NDFom, ADFom, lignin(sa), B₃ and C; while CP, TP, ash, Ca, P, K, SP, A, B₁, B₂, nitrate, total and soluble oxalic acid, IVGP, b (i.e., gas production from the insoluble fermentable fractions at 120 h), c (i.e., rate of gas production during incubation), OMD and NDFD decreased (P<0.05). With increasing N fertilization rate, CP, TP, EE, P, nitrate, oxalic acid, SP, A, b, OMD and NDFD increased (P<0.05), however B₂ declined (P<0.05). Increasing N fertilization increased yield, CP concentration and nutrient digestibility. At 40 d after planting use of amaranth forage as a ruminant feed is limited due to its high nitrate content. However, at 60 d, although a depression in digestibility and CP content occurred, this forage has the potential as a ruminant feed due to the much lower nitrate levels.