Sweet Sorghum Research Articles

ASSESSMENT OF THE EFFECT OF BIOCHAR ON THE PROCESS OF THERMOLISIS OF BIOMASS OF PLANTS GROWN ON RECLAIMED LANDS

Samples of soil contaminated with heavy metals for pot experiments with annual crops (maize, sweet and sudan sorghum) were taken near the mines "Pavlogradska" and "Blagodatna" in the coal-mining region of Western Donbass. The basis of the reclaimed areas was an 8-10 m thick mine rock (MR) dump, covered with different layers of black soil or red-brown clay by creating two types of soil artificial profiles with the addition of 30 cm of black soil (30 cm of BS +MR) and 50 cm red-brown clay (50 cm RBC + MR). Experimental soil samples were treated with 3.0% (w/w) biochar. The purpose of the study was to study the effect of the addition of biochar on the process of thermal destruction of the biomass of maize, sweet and sudan sorghum, grown on different substrates - components of artificial reclaimed profiles (upper layers of chernozem mass and red-brown clay). The process of thermolysis of biomass components of three agricultural crops was studied by the method of thermogravimetric analysis. Thermal destruction of the biomass of the three studied plant species occurred in two stages: evaporation of water and volatile compounds (stage 1) and decomposition of the main components: hemicellulose, cellulose and lignin (stage 2). The first stage took place in the temperature range of 50-180°С. The process was slow, the maximum speed did not exceed 5-8%/min, the extreme point was observed at a temperature of 100-110°C. Loss of body weight is insignificant, 4.5–7.5%. The second stage is divided into two phases: the decomposition of holocellulose with the beginning of lignin decomposition (phase 1) and the cessation of lignin decomposition, and the formation of non-combustible residue (phase 2). Destruction of holocellulose occurred in the temperature range of 190-390°С. Due to the large amount of hemicellulose in the biomass of the studied plants, its decomposition was shifted to the region of higher temperatures. Therefore, the degradation ranges of hemicellulose and cellulose overlapped, and only one extreme point was observed in the DTG curves. The process proceeded at high speeds with the peak of destruction in the temperature range of 280-310°C. Weight loss was also the most significant and was between 50 and 55%. Decomposition of lignin occurred rather slowly, with one insignificant peak in the temperature range of 420-440°C. A weight loss of 26-30% has been established. At the first stage, the process proceeded mainly with heat absorption; the reactions of the second stage were exothermic with noticeable thermal effects in the zones of cellulose and lignin decomposition. Differences in thermal characteristics of sugar sorghum biomass grown on different substrates and with the addition of biochar were determined in the process of thermolysis. Degradation of holocellulose occurred more slowly in biomass collected from a vessel with red-brown clay, in contrast to lignin, which decomposed faster than in the experiment where the substrate was a loose layer of chernozem. The share of non-combustible residues was almost 2 times smaller. A slight increase in the rate of the cellulose decomposition reaction (1,2 times) and a significant increase in the rate of the lignin destruction reaction (5 times) was observed. In the treatment with biochar, a more complete combustion of biomass was observed. The rate of cellulose decomposition in the experiment with red-brown clay became somewhat higher, although the decomposition of lignin occurred more slowly. The share of non-combustible residues increased by 1,8 times. Thermal destruction of Sudan grass biomass on both substrates occurred in a similar manner. The addition of biochar did not reveal significant deviations in the thermal behavior of biomass grown on chernozem, in contrast to the experiment with red-brown clay, where the addition of biochar contributed to a significant reduction in the duration of thermolysis. The first stage of thermolysis of corn biomass was somewhat shorter in the experiment with a bulk layer of chernozem compared to red-brown clay and was accompanied by a lower mass loss. The same trend was observed in the decomposition of holocellulose. At the same time, the destruction of lignin in the version with chernozem lasted longer, the extremum point was shifted to the region of higher temperatures, the speed of the process was almost twice as low as in the version with clay, and the proportion of non-combustible residue was 1,7. times higher. More complete combustion of corn biomass was also observed in the version with biochar.

Isolation and characterization of Azotobacter sp. for plant growth promotion and abiotic stress tolerance in Telangana's agro-climatic regions: Towards sustainable development

Current study was done to understand and improve plant survival and growth under biotic and abiotic stress tolerance was considered. The primary goal of this work was to isolate azotobacterial species from indigenous places where the agriculture community has been practicing traditional methods along with regular places, also examined the areas of stressed agriculture areas which are seasonally cultivated and environments in their capacity to enhance drought stress tolerance brought from different crop fields such as Maize, sweet Sorghum, Sugarcane, corn, and wheat to increase the yield.These crops soil samples were taken from few drought areas tolerant places, i.e. under different temperature, salinity, pH and moisture conditions of those particular areas in Telangana. The different soil samples isolated for azotobacter strains from different regions in Telangana were collected and analyzed for growth in media to get the high yield for the agriculture purpose which will benefit the agricultural community and leads to sustainable development. Morphological, biochemical, and molecular characteristics were used to evaluate the Azotobacter species. Azotobacter beijerinckii strain and Azotobacter tropicalis strain were identified by biochemical testing and 16s rRNA sequencing. Azotobacter beijerinckii strain (BKPOU06TS) and Azotobacter tropicalis strain (BKPOU08TS) 16S rRNA sequences were submitted to GenBank with accession numbers OP536202 and OP536206, respectively.

Heritability, genetic advance, and correlation studies of morpho-agronomic traits and brix in Burkina Faso sweet stalk sorghum genotypes

Heritability, genetic advance, and correlation studies of morpho-agronomic traits and brix in Burkina Faso sweet stalk sorghum genotypes

Effect of processing of sweet sorghum bagasse based complete diet on growth and carcass traits in growing Ram Lambs

Kumari, N.N., Reddy, Y.R., Nagalakshmi, D. and Vidya, B. 2023. Effect of processing of sweet sorghum bagasse based complete diet on growth and carcass traits in growing ram lambs. Animal Nutrition and Feed Technology, 23: 65–75.

Physiological maturation of sweet sorghum seeds produced under water restriction

Physiological maturation of sweet sorghum seeds produced under water restriction

In vitro nutritional evaluation of hybrids and open-pollinated varieties of sweet Sorghum crop in Goats

The present study was conducted to compare the nutritional evaluation of sweet sorghum [Sorghum bicolor (L.)] hybrids and open-pollinated varieties. Two each of sweet sorghum hybrids (PAC52093, SPSSH19) and open-pollinated varieties (SPSSV15, SPSSV20), were planted at four locations viz., two locations each in Sithouli and Turari villages of Gwalior district during rainy season 2021. Crude protein content was significantly (P<0.01) higher in SPSSH19 and neutral detergent fibre was significantly (P<0.01) lower in PAC52093 hybrid of sweet sorghum in comparison to other varieties. Dry matter yield was higher in SPSSH19 (250.0±1.0 q/ha) in comparison to PAC52093 (229.0±1.0 q/ha), SPSSV15 (228.0±1.0 q/ha) and SPSSV20 (227.0±1.0 q/ha). The digestibility of dry matter, organic matter, crude protein, neutral detergent fibre, acid detergent fibre, cellulose and hemicellulose was similar among the hybrids and varieties (P>0.05). In conclusion, hybrid SPSSH19 was superior in dry matter yield and digestible crude protein contents in comparison to other hybrids and varieties.

Thymol-menthol-based deep eutectic solvent as a modifier in reactive liquid–liquid extraction of carboxylic acids from pretreated sweet sorghum silage press juice

Reactive liquid–liquid extraction has been widely investigated as a means of isolating carboxylic acids from fermentation broths. However, commonly applied fossil-based solvent phases should be replaced by green alternatives. In this work, we investigate a thymol-menthol-based deep eutectic solvent (tmDES) as a green alternative to the commonly applied modifier 1–octanol for the extraction of lactic acid, acetic acid, and oxalic acid from a model solution and pre-treated sweet sorghum silage press juice (pSPJ); tri–n–octylamine (TOA) was used as a reactive extractant. Additionally, NMR spectroscopy was used to detect interactions between menthol and thymol molecules, as well as among these and TOA and lactic acid. NMR measurements of tmDES revealed the existence of multiple intermolecular contacts between thymol and menthol. Furthermore, nuclear Overhauser effects (NOEs) between the tmDES, TOA, and lactic acid molecules were found. Extraction experiments showed that tmDES improves the extraction efficiency when using pSPJ as the feed phase. The maximum extraction efficiency for lactic acid increased from 35.0 ± 0.8 % to 48.7 ± 0.7 % and for acetic acid from 52.4 ± 0.2 % to 82.2 ± 0.6 % when using a tmDES instead of 1–octanol at 50 °C. Furthermore, the use of tmDES resulted in higher extraction efficiencies as compared to the use of 1–octanol at equilibrium pH values ranging from five to seven, which is a common pH range for fermentation. Besides having superior biocompatibility and extraction efficiency as compared to 1–octanol, tmDES allow carboxylic acid extraction processes to be carried out at higher pH levels.

Productivity of sweet sorghum hybrids depending on harvesting periods in the conditions of the Western Polissya

Purpose. Increasing the efficiency of growing domestically bred sugar cultivation for bioethanol by optimizing the elements elements of the cultivation technology. Methods. Field, laboratory, visual, measuring and weighing, mathematical and statistical. Results. According to the results of a results carried out in 2019–2020 under of Western Polissya, it was found that sugar sorghum for the of biogas should be harvested in September, as maximum root biofuel in this period. Conclusions. When growing hybrid largest amount of green mass (79.8 t/ha) and the maximum output of biogas — 16.75 thousand m3/ha and energy — 365.2 GJ/ha. Obtaining high productivity of sugar sorghum as a raw material for the production of biofuel is possible only with the use of modern hybrids with a sufficient level of productivity.

THE EFFECTS OF SOWING DESIGNS ON FORAGE YIELD AND QUALITY OF SWEET SORGHUM AND MUNG BEAN MIXTURES UNDER MEDITERRANEAN CONDITIONS

This study was conducted to determine the effects of sowing designs on forage yield and quality in sweet sorghum and mung bean grown as binary mixture with different cultivation systems in Mediterranean conditions under second crop season during 2019-2020. As sowing design, twin-row (20×55 cm row spacing), narrow-row (55 cm row spacing) and conventional-row (75 cm row spacing) were used as sowing design. The mixtures were formed based on the plant density and alternative row numbers of sweet sorghum and mung bean. Sowing was done on alternating rows of 1 row of sweet sorghum and 1 row of mung bean and 2 rows of sweet sorghum and 1 row of mung bean. The plant density of sweet sorghum was 14 plants m-2 and plant densities of mung bean were 14 plants m-2, 21 plants m-2 and 28 plants m-2. This experiment was planned as two-factor (sowing designs and mixtures) and conducted in randomized complete block design arranged in split plot with 3 replications. To evaluate the forage yield and quality, fresh forage yield, dry matter yield, NDF, ADF, ADL, crude ash crude protein and ether extract characteristics were examined. In addition, the intercropping potential of mung bean and sweet sorghum mixtures was evaluated by the land equivalent ratio. As a result of the present study, mixed cultivation of 14 plants m-2 with one row of sweet sorghum and 14 plants m-2 with one row of mung bean gave the best results in narrow row sowing design. It was concluded that an efficient and high quality intercropping system can be realized in the second crop conditions in regions where Mediterranean climatic conditions prevail, especially for mung beans and sweet sorghum.

INFLUENCE OF DIFFERENT CONDITIONS OF MINERAL NUTRITION ON YIELD OF SWEET SORGHUM SEEDS IN THE CONDITIONS OF THE SOUTHERN FOREST-STEPPE OF WESTERN SIBERIA

Sorghum occupies a significant place in world agriculture and is of particular value in intensive feed production. The selection of agricultural practices for increase of seed productivity is relevant and current, since the availability of own seeds is of decisive importance in reduction of feed production cost. The studies were carried out in Omsk region in 2013, 2015–2017 in a stationary field experiment in eight-field crop rotation. The aim of the work is to study the influence of mineral nutrition conditions on yield of sweet sorghum seeds, water and nutritional regimes of meadow-black soil in the conditions of the south of Western Siberia. The experiment included a three-factor scheme: the supply of soil with mobile phosphorus according to Chirikov (factor A) - average, 50-100 mg/kg (background 0); increased, 100-120 mg/kg (I) and 140-150 mg/kg (II); high, 150-200 mg/kg (III); phosphorus fertilizer (factor B) - P0, P60; nitrogen fertilizer (factor C) - N0, N30, N60. The field experiment was implemented by mutual method of pre-sowing application of mineral fertilizers and different levels of phosphorus in the soil. The soil is meadow-black soil, medium-thick, medium-humus, heavy loamy. The reaction of the soil environment in the arable layer is neutral, the depth of groundwater in spring is 2.86, in autumn - 3.09 m. The climate of the southern forest-steppe of Omsk region is suitable for sweet sorghum cultivation with insufficient moisture in some years and uneven distribution of precipitation during the growing season. The yield of sweet sorghum seeds ranged from 2.93 to 3.46 t/ha on average for 3 years, depending on the background, the largest yield increase was noted on 0 background (N60P60) with a natural level of mobile phosphorus and pre-sowing application of nitrogen and phosphorus fertilizers. It is possible to obtain seeds of sweet sorghum in the southern forest-steppe of Omsk region. To achieve high yields on soils with an average content of mobile phosphorus, it is necessary to use nitrogen and phosphorus fertilizers. It is also indispensable to select an early ripening variety capable of forming high quality seeds in the specific conditions of Siberia.

Preparation of microcrystalline cellulose from agricultural residues and their application as polylactic acid/microcrystalline cellulose composite films for the preservation of Lanzhou lily

Microcrystalline celluloses were isolated from four agricultural residues, including sweet sorghum stalk, Jerusalem artichoke stalk, grains stillage, and Chinese herb residue, and characterized in terms of physicochemical and structural properties. The obtained microcrystalline celluloses were composited with polylactic acid as a packing film for the preservation of Lanzhou lily. All the agricultural residues-derived microcrystalline celluloses were in cellulose Iβ structure with high purity and good thermal stability. Microcrystalline celluloses from sweet sorghum stalk had a higher degree of polymerization (327) and crystallinity (70.52 %) than others. The preservation effect of lily bulbs packaged by films were significantly improved indicated by the lessened weight loss rate and the meliorative hardness and whiteness, which ascribe to the repressed oxidation reactions. Polylactic acid/microcrystalline cellulose composite films prepared from sweet sorghum straw have been proved the most effective. This work could offer a value-added outlet for agricultural residues to produce microcrystalline celluloses-based biocompatible films for preservation of Lanzhou lily.

Overexpressing GRE3 in Saccharomyces cerevisiae enables high ethanol production from different lignocellulose hydrolysates.

The efficiently renewable bioethanol can help to alleviate energy crisis and environmental pollution. Genetically modified strains for efficient use of xylose and developing lignocellulosic hydrolysates play an essential role in facilitating cellulosic ethanol production. Here we present a promising strain GRE3OE via GRE3 overexpressed in a previously reported Saccharomyces cerevisiae strain WXY70. A comprehensive evaluation of the fermentation level of GRE3OE in alkaline-distilled sweet sorghum bagasse, sorghum straw and xylose mother liquor hydrolysate. Under simulated corn stover hydrolysate, GRE3OE produced 53.39 g/L ethanol within 48 h. GRE3OE produced about 0.498 g/g total sugar in sorghum straw hydrolysate solution. Moreover, GRE3OE consumed more xylose than WXY70 in the high-concentration xylose mother liquor. Taken together, GRE3OE could be a candidate strain for industrial ethanol development, which is due to its remarkable fermentation efficiency during different lignocellulosic hydrolysates.

Response of sugarcane aphid (Melanaphis sacchari) to interactive effects of soil drenched triterpenoid phytonematicides in sweet sorghum (Sorghum bicolor)

Triterpenoid phytonematicides, namely, Nemarioc-AL, Nemafric-BL and Mordica, when drench-applied each consistently suppressed root-knot nematode population densities, with limited information on whether the products could induce any systemic effects that would suppress sugarcane aphid population densities and reproductive potential. The objective of the study was therefore to determine the interactive effects of soil-drenched triterpenoid phytonematicides on aphid population densities and their reproductive factors. A 2× 2× 2 factorial experiment was laid out in a randomised complete block design with six replications during 2020-21 and 2021-22 growing seasons in Limpopo Province, South Africa. Each sweet sorghum seedling was infested with 5 adult M. sacchari, with appropriate treatment combinations drench-applied weekly. At 150 days after infestation, treatments had highly significant effects on aphid population densities and reproductive factors. Relative to untreated control, the second order interaction and the three first order interactions reduced aphid population densities by 92, 75, 79 and 80%, respectively. In conclusion, soil-drenched triterpenoid phytonematicides induced systemic effects in sweet sorghum, which significantly suppressed population densities of M. sacchari.

Osmotic stress resistance of different sorghum species affected by NaСl

Introduction. One of the most urgent issue of plant production which attracts the attention of many researchers and farmers, is salt tolerance of plants. Salinity has a negative effect, caused by the disruption of an osmotic balance of a cell that negatively affects water regime of plants. At the same time, plants experience growth inhibition and reduce their yield.The purpose of the study was to estimate resistance of different sorghum species to chloride salinity and to identify the most resistant genotypes.Methods. The study was carried out in the laboratory for plant physiology in 2018–2021. For the current study there has been carries out a modelling of a salt stress by a pure salt solution (concentration of 13 atm.) according to a conventional methodology, the control was distilled water.Results. There has been established the salinity stress effect on seed germination of different sorghum species. The values of germination energy and laboratory germination of grain sorghum were 53.1% and 62.0%; of sweet sorghum — 39.1% and 43.1; the values of Sudan grass — 30.1 and 33.5%, respectively. In the first and second groups — of highly resistant and resistant species (seed germination affected by salinity ranged from 61 to 100%) — were are 61% of grain sorghum genotypes, 56% of sugar sorghum genotypes and 6% of Sudan grass genotypes. There has been established a resistance degree and identified some features of the development of varieties with different degrees of resistance to this stress (length of sprouts and primary roots). Grain sorghum was found less susceptible to salinity stress of all studied species. Among grain sorghum samples, 9 genotypes have demonstrated the highest salinity resistance with a germination rate from 87.5 (Uch. 22/20) to 95.9% (Uch. 29/20). The maximum values were shown by the samples of Uch. 29/20 (95.95%), Uch. 20/20 (93.9%), Uch. 21/20 (93.8%), Jetta x Uch. 45/20 (91.5%) and Uch. 7/20 (90.8%), which indicated the ability to tolerate severe salinity concentration.

Physicochemical analysis and intermediate pyrolysis of Bambara Groundnut Shell (BGS), Sweet Sorghum Stalk (SSS), and Shea Nutshell (SNS)

ABSTRACT The current work focused on the intermediate pyrolysis of Bambara Groundnut Shells (BGS-G1), Sweet Sorghum Stalk (SSS), and Shea Nutshells (SNS). These feedstocks are readily available as wastes or by-products from industrial and agricultural activities. The thermo-gravimetric analysis of the biomass samples exhibited decomposition and devolatilization potentials in the temperature range of 110–650°C. The kinetic modelling resulted in the activation energy of BGS G1 being the lowest as 20.43 kJ/mol and SNS as the highest 24.89 kJ/mol among the three biomass samples. Intermediate pyrolysis was conducted in a vertical tube reactor at a temperature of 600°C, with nitrogen flow at 10 ml/min and heating rate ≥ 33.0℃/min. The yield of pyrolysis bio-oil was 38.0 ± 6.4, 44.2 ± 6, and 39.7 ± 5.2 wt.% for BGS-G1, SSS, and SNS, respectively. The HHV of bio-oil varied as 23.7 ± 1.8, 23.8 ± 1.8, to 26.5 ± 2.0 MJ/kg for BGS-G1 SSS and SNS respectively. The biochar recorded the lowest HHV for BGS-G1 as 18.8 ± 1.2 MJ/kg and the highest for SNS as 26.4 ± 1.8 MJ/kg. The FTIR of bio-oil revealed significant functional groups, and GC-MS (Gas Chromatography and Mass Spectrometry) analysis categorized the compounds in bio-oils as ketones, furans, phenolics, acids, phenols and benzene derivatives. The physicochemical analysis of the feedstocks and the products (bio-oil and biochar) showed their potential for bioenergy and biochemical (green chemicals) production.

Insect Feeding on Sorghum bicolor Pollen and Hymenoptera Attraction to Aphid-Produced Honeydew.

Pollinators are declining globally, potentially reducing both human food supply and plant diversity. To support pollinator populations, planting of nectar-rich plants with different flowering seasons is encouraged while promoting wind-pollinated plants, including grasses, is rarely recommended. However, many bees and other pollinators collect pollen from grasses which is used as a protein source. In addition to pollen, Hymenoptera may also collect honeydew from plants infested with aphids. In this study, insects consuming or collecting pollen from sweet sorghum, Sorghum bicolor, were recorded while pan traps and yellow sticky card surveys were placed in grain sorghum fields and in areas with Johnsongrass, Sorghum halepense to assess the Hymenoptera response to honeydew excreted by the sorghum aphid (SA), Melanaphis sorghi. Five genera of insects, including bees, hoverflies, and earwigs, were observed feeding on pollen in sweet sorghum, with differences observed by date, but not plant height or panicle length. Nearly 2000 Hymenoptera belonging to 29 families were collected from grain sorghum with 84% associated with aphid infestations. About 4 times as many Hymenoptera were collected in SA infested sorghum with significantly more ants, halictid bees, scelionid, sphecid, encyrtid, mymarid, diapriid and braconid wasps were found in infested sorghum plots. In Johnsongrass plots, 20 times more Hymenoptera were collected from infested plots. Together, the data suggest that sorghum is serving as a pollen food source for hoverflies, earwigs, and bees and sorghum susceptible to SA could provide energy from honeydew. Future research should examine whether planting strips of susceptible sorghum at crop field edges would benefit Hymenoptera and pollinators.

Characterization of starch structures isolated from the grains of waxy, sweet, and hybrid sorghum (Sorghum bicolor L. Moench).

In this study, starches were isolated from inbred (sweet and waxy) and hybrid (sweet and waxy) sorghum grains. Structural and property differences between (inbred and hybrid) sweet and waxy sorghum starches were evaluated and discussed. The intermediate fraction and amylose content present in hybrid sweet starch were lower than those in inbred sweet starch, while the opposite trend occurred with waxy starch. Furthermore, there was a higher A chain (30.93-35.73% waxy, 13.73-31.81% sweet) and lower B2 + B3 chain (18.04-16.56% waxy, 24.07-17.43% sweet) of amylopectin in hybrid sorghum starch. X-ray diffraction (XRD) and Fourier transform infrared reflection measurements affirm the relative crystalline and ordered structures of both varieties as follows: inbred waxy > hybrid waxy > hybrid sweet > inbred sweet. Small angle X-ray scattering and 13C CP/MAS nuclear magnetic resonance proved that the amylopectin content of waxy starch was positively correlated with lamellar ordering. In contrast, an opposite trend was observed in sweet sorghum starch due to its long B2 + B3 chain content. Furthermore, the relationship between starch granule structure and function was also concluded. These findings could provide a basic theory for the accurate application of existing sorghum varieties precisely.

Biomass and Dry Matter Yield Potential of Some Early Sweet Sorghum (Sorghum bicolor var. saccharatum (L.) Mohlenbr.) Genotypes

Sweet sorghum plant is a warm season annual crop. It can be used for animal feeding in the one-cut agricultural system. Sweet sorghum is grown for the purpose of fresh and dry grass and for silage production. Biomass of sweet sorghum is nutritive due to sweet sorghum stalk contains 15-20% sugar. The study aimed to determine biomass, dry matter yield and some agricultural characteristics of some early sweet sorghum genotypes. Research was carried out during the second crop-growing season of 2016 at the Eyyubiye campus of experimental area of the Harran University in Sanliurfa, Turkiye. The experiment was designed as complete randomized blocks design with four replicates. This study utilized 12 early sweet sorghum genotypes as crop material. The experiment investigated some yield characteristics such as cluster formation period, plant height, stalk diameter, stalk ratio, leaf ratio, cluster ratio, dry matter yield and biomass yield. Results showed significant differences between the genotypes for tested characteristics (P≤0.01). Cluster formation period values ranged from 54.25 to 69.00 day, plant height from 252.25 to 340.75 cm, stalk diameter from 19.15 to 25.60 mm, stalk ratio from 75.72% to 86.75%. Leaf ratio values varied between 8.83% and 15.98%, cluster ratio between 4.40% and 10.31%. Dry matter yield values were between 2918.12 and 8456.25 kg da-1, biomass yield values between 9283.5 and 18400.0 kg da-1. Findings revealed that UNLY-hybrid-4, Rox Orange, Blue Ribben, and Colman sweet sorghum cultivars gave higher values than others in terms of plant height, dry matter yield and biomass yield.

Transcriptional regulation of the raffinose family oligosaccharides pathway in Sorghum bicolor reveals potential roles in leaf sucrose transport and stem sucrose accumulation.

Bioenergy sorghum hybrids are being developed with enhanced drought tolerance and high levels of stem sugars. Raffinose family oligosaccharides (RFOs) contribute to plant environmental stress tolerance, sugar storage, transport, and signaling. To better understand the role of RFOs in sorghum, genes involved in myo-inositol and RFO metabolism were identified and relative transcript abundance analyzed during development. Genes involved in RFO biosynthesis (SbMIPS1, SbInsPase, SbGolS1, SbRS) were more highly expressed in leaves compared to stems and roots, with peak expression early in the morning in leaves. SbGolS, SbRS, SbAGA1 and SbAGA2 were also expressed at high levels in the leaf collar and leaf sheath. In leaf blades, genes involved in myo-inositol biosynthesis (SbMIPS1, SbInsPase) were expressed in bundle sheath cells, whereas genes involved in galactinol and raffinose synthesis (SbGolS1, SbRS) were expressed in mesophyll cells. Furthermore, SbAGA1 and SbAGA2, genes that encode neutral-alkaline alpha-galactosidases that hydrolyze raffinose, were differentially expressed in minor vein bundle sheath cells and major vein and mid-rib vascular and xylem parenchyma. This suggests that raffinose synthesized from sucrose and galactinol in mesophyll cells diffuses into vascular bundles where hydrolysis releases sucrose for long distance phloem transport. Increased expression (>20-fold) of SbAGA1 and SbAGA2 in stem storage pith parenchyma of sweet sorghum between floral initiation and grain maturity, and higher expression in sweet sorghum compared to grain sorghum, indicates these genes may play a key role in non-structural carbohydrate accumulation in stems.

Energy Assessment of Second-Generation (2G) Bioethanol Production from Sweet Sorghum (Sorghum bicolor (L.) Moench) Bagasse

Sweet sorghum bagasse (SSB) provides a raw material rich in polysaccharides that can be converted into biofuel and other high-value-added bioproducts under the biorefinery concept. The aim of this study was to evaluate the effect of hydrothermal pretreatment on the availability of SSB fermentable sugars for bioethanol production, considering the energy balance of the process. For this, the biomass was subjected to one process, pre-saccharification simultaneous and fermentation (PSSF). Previously, the temperature, time, and particle size effect were determined, as well as the enzymatic load for the more significant release of monomeric sugars. It was observed that the increase in the pretreatment severity, defined by the severity factor [log(Ro)], resulted in a more significant release of sugar and energy consumption. In the PSSF, bioethanol production was 22.17 g/L, with a total energy consumption of 2.46 MJ/g of processed biomass, of which 79.14% was by concept of electricity.