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Sweet pearl millet [Pennisetum glaucum (L.) R. Br.] and sweet sorghum [Sorghum bicolor (L.) Moench], previously tested for ethanol production, were evaluated as high sugar crops for animal feeds to possibly replace silage corn (Zea mays L.). We compared the forage yield, nutritive value, and ensilability of one hybrid of sweet pearl millet and two of sweet sorghum to a locally adapted silage corn hybrid in five Canadian ecozones. Forage yields of sweet pearl millet and sorghum were similar to that of silage corn in the Boreal Shield, Mixedwood Plain, and Atlantic Maritime ecozones, greater in the Prairies, and lower in the Pacific Maritime ecozone. Across sites, forage dry matter concentration was less for sweet pearl millet (289 g kg−1) and sweet sorghum (245 g kg−1) than for silage corn (331 g kg−1). Sweet pearl millet had a lower total digestible nutrient (TDN) concentration (452 g kg−1 DM) and aNDF digestibility (NDFd) than sweet sorghum and silage corn along with greater neutral detergent fibre (aNDF) and water-soluble carbohydrate (WSC) concentrations than silage corn. Sweet sorghum had greater aNDF and WSC, lower starch, and similar TDN (534 g kg−1 DM) concentrations, but greater NDFd compared with silage corn. Sweet pearl millet and sorghum fermented as well as silage corn, reaching low pH values and acceptable concentrations of lactic and volatile fatty acids. Sweet sorghum is therefore a viable alternative to silage corn in Canada except in the Pacific Maritime ecozone, but early-maturing hybrids with acceptable DM concentration at harvest are required.

Effects of harvest time on bioethanol production and bagasse characteristics for combustion and forage in sweet sorghum

Sweet sorghum stalks were used as a low cost carrier for immobilization of Saccharomyces cerevisiae NP 01 to produce ethanol from sweet sorghum juice. The effects on ethanol production of carrier size (6 × 6 × 6 to 20 × 20 × 20 mm3) and initial cell concentrations (5 × 107 to 2 × 108 cells mL−1) for cell immobilization were investigated. The ethanol production medium was the juice containing 230 g L−1 of total sugar without nutrient supplementation. The fermentations were carried out under static conditions in 500-mL air-locked Erlenmeyer flasks at 30 °C. The results showed that the optimum size of sorghum stalk pieces for repeated-batch ethanol production was 6 × 6 × 6 mm3, while the optimum initial cell concentration for the immobilization was 1.0 × 108 cells mL−1. The immobilized yeast under these conditions could be used for at least eight successive batches without any losses of ethanol production efficiencies. The average ethanol concentration, productivity and yield of the eight successive batches were 99.28 ± 3.53 g L−1, 1.36 ± 0.05 g L−1 h−1 and 0.47 ± 0.03 g g−1, respectively.

Sweet sorghum [Sorghum bicolor (L.) Moench] is one of the varieties of sorghum having stalk with high concentration of soluble sugar. Biochemical evaluations of sweet sorghum enable it to determine the potential of the crop to be utilized for sugar production at industrial level. This study was designed to evaluate the Ethiopian sweet sorghum germplasms for production of crystalized sugar. In this study, 91 sweet sorghum accessions were evaluated based on total soluble sugar content. As a result, 8 accessions having high total soluble sugar scores were selected and evaluated for further biochemical quality traits. In addition, three agronomic parameters were used to evaluate their effect on the biochemical features of the studied sweet sorghum and sugarcane accessions. These traits include total soluble sugar (degree brix), polarization, sucrose content, sugar purity, days to maturity, stem height and stalk diameter. Three high quality sugarcane (Saccharum officinarum) genotypes collected from Kessem sugar industry of Ethiopia were used as standard checks. Analysis of variance (ANOVA); mean separation and correlation were analyzed using R-software. ANOVA revealed significant variations for polarization value and purity of sweet sorghum juice at p ≤ 0.001. The mean separation analysis revealed that maximum and minimum degree brix were obtained from T-11 (20.23%) and T-28 (16.88%), respectively. In the present study, the polarization values ranged from 41.57 (T-28) to 69.30 0Z (C-86/12).The three sugarcane standard cheeks showed relatively higher values of polarization in comparison with the sweet sorghum accessions. Among the sweet sorghum accessions, T-13 showed relatively higher polarization value whereas the remaining sweet sorghum accessions didn’t show significant variation. The average sucrose content (pol percentage) was ranged from 11.98% (T-28) to 16.77% (C-86/12). C-86/12 sugarcane accession showed the highest (16.77%) mean value for sucrose content whereas T-28 sweet sorghum accession scored the lowest sucrose content (11.98%). Maximum purity of sugar was recorded from SP-70 (90.77%) sugarcane accession whereas; the minimum value was recorded from T-11 (63.62%) sweet sorghum accession. In addition, the correlation analysis revealed that there were both positive and negative correlation among biochemical and agro morphological traits of sweet sorghum and sugarcane. Brix value showed positive correlation with polarization (0.56**) and sucrose content (0.71**) while it was negatively correlated with sugar purity (-0.06), days to maturity (-0.06), stem height (-0.19) and stalk diameter (-0.16). On the other hand, polarization showed strong positive correlation with sucrose content (0.95**), purity (0.76**) and days to maturity (0.78**). In comparison with sugarcane, the studied sweet sorghum accessions revealed quite lower performance in polarization, sucrose content and purity. Nevertheless, this study confirmed the existence of a climate smart and promising sweet sorghum genotypes used for the production of sugar and syrup as an alternative sweetener.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-21488-3.

Optimizing N fertilizer inputs is imperative for improving sweet sorghum [Sorghum bicolor (L.) Moench] yields and biofuel feedstock system efficiency. A 2‐yr study was conducted to determine the physiological N‐use efficiency (NUE) response in sweet sorghum's ethanol yield of stem juice, bagasse, and total ethanol yield (TEY). Two sweet sorghum cultivars (‘Dale’ and ‘Top 76–6’) were fertilized at five N fertilizer rates (0, 56, 112, 168, and 224 kg ha−1). At harvest, the stem juice and bagasse yields were measured then analyzed for the corresponding N concentrations and N contents. Whole‐plant N recovery efficiency ranged from −1.5 to 57.6% across both years, with a significant N rate effect only in one study year. The NUE of juice ethanol yield only demonstrated an N response in the second year, whereas the NUE of lignocellulosic ethanol yield was greatest at the 56 kg ha−1 fertilizer rate each year. The NUE of total theoretical ethanol yield, determined as the sum of juice and bagasse conversion to ethanol, averaged 169 L EtOH kg−1 N across both years and was greatest at the 56 kg N ha−1 fertilizer rate in both years, and decreased at N rates exceeding 56 kg ha−1 in only one of the years. This study revealed that although sweet sorghum ethanol yields increased with N fertilizer application, NUE was greatest with low N fertilizer rates, consistent with previous research indicating that sweet sorghum is an appropriate biofuel feedstock for production in low‐input systems or on marginal lands.Core Ideas Nitrogen recovery and use efficiencies of sweet sorghum juice and bagasse were measured for two years in Missouri. Nitrogen recovery efficiency was greatest in one study year when 224 kg N ha−1 was applied, with no differences in recovery in the second year. The N use efficiency of estimated total ethanol yield was greatest at 56 kg N ha−1.

In order to utilize sweet sorghum grain protein (SSGP) for food applications, SSGP was hydrolyzed by alcalase to produce the hydrolysates with ACE-inhibitory activity. The Plackett-Burman design (PBD) was used to identify the important factors influencing the ACE-inhibitory activity of SSGP hydrolysates. The result of PBD indicated that hydrolysis temperature, pH and alcalase dosage had significant influence (P andlt; 0.05) on the ACE-inhibitory activity of SSGP hydrolysates. Response surface methodology (RSM) was applied to optimize the three significant factors. The optimum hydrolysis conditions obtained from RSM were as follows: hydrolysis temperature 56 and#176;C, pH 8.0, alcalase dosage 5200U/g. Under the optimum conditions, SSGP hydrolysates contained 24.3% 1–5 kDa (IC50=0.305 mg/ml) and 15.2% andlt;1 kDa (IC50=0.116 mg/ml) peptide fractions having potent in vitro ACE inhibitory activities. Moreover, the inhibition pattern against ACE investigated using Lineweaver–Burk plots revealed that the peptides with molecular weights above 5 kDa in the SSGP hydrolysates were non-competitive inhibitors with inhibition constants (Ki) between 1.098 and 1.171 mg/ml, while the peptides with molecular weights below 5 kDa in the hydrolysates were competitive inhibitors with Ki between 0.110 and 0.184 mg/ml. The results of this study suggest that SSGP may be considered as a source of functional ingredients for the prevention of hypertension.

<p><strong>Background.</strong> The most commonly used raw materials for ethanol production are maize (<em>Zea mays</em> L.) and sugarcane (<em>Saccharum</em> <em>officinarum </em>L.). A specie that is gaining importance because of its comparative advantages over other energy crops is sweet sorghum (<em>Sorghum bicolor</em> (L.) Moench). The seasonality of production, which limits the continuous supply of sweet sorghum to the industry for ethanol production, is one of the limitations of this crop. <strong>Objective. </strong>To evaluate the biomass and sugar production of sweet sorghum genotypes for different sowing dates in Veracruz, Mexico conditions. <strong>Methodology.</strong> The development of ten genotypes was determined during the autumn-winter (October 2013), winter-spring (February 2014) and spring-summer (April 2014) cycles. Three genotypes were also tested on five planting dates: June 19th, July 1st, August 1st, September 1st, and October 2nd, at the Cotaxtla Experimental Station of the Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias (INIFAP), located in the municipality of Medellín de Bravo, Veracruz, México. <strong>Results.</strong> Sweet sorghum developed in all cropping seasons, but the highest productivity was obtained in the spring-summer. Stem biomass, sugar concentration, juice volume, and sugar production were highest in June, July, and August, following planting. As the planting date was later, the values decreased. <strong>Implications.</strong> The optimal planting date for sweet sorghum cultivation in the state of Veracruz was identified. This information will be helpful for producers to obtain higher biomass yields and for the ethanol industry to plan sweet sorghum production as a complementary raw material to sugarcane. <strong>Conclusions.</strong> The optimum sweet sorghum planting period for producing biomass and sugars under Veracruz, Mexico, conditions is during June, July, and August.</p>

The production of wine from green grains of sweet sorghum presents an innovative approach to diversifying the wine industry and utilizing agricultural resources more efficiently. Sweet sorghum, a C4 grass species, is gaining attention for its potential as a bioenergy crop, but its applications extend beyond fuel production. This paper explores the feasibility and process of transforming green grains of sweet sorghum into wine, highlighting the biochemical composition of sweet sorghum, the fermentation process, and the potential challenges and opportunities associated with this novel approach to winemaking. Sweet sorghum, known scientifically as Sorghum bicolour (L.) Moench, is a versatile crop with high biomass and sugar content, making it an ideal candidate for biofuel production. However, the grains of sweet sorghum also contain fermentable sugars that can be utilized in winemaking. The biochemical composition of sweet sorghum grains includes starch, sucrose, glucose, fructose, and amino acids, providing ample substrates for yeast fermentation. The process of producing wine from green grains of sweet sorghum involves several key steps. Firstly, the grains are harvested at the green stage to capture their high sugar content before they mature and lose sweetness. The grains are then processed to extract the juice, which serves as the raw material for fermentation. Next, the juice undergoes clarification and may be supplemented with nutrients to support yeast growth and fermentation efficiency.

Sweet sorghum has become a candidate species for combining phytoremediation with biofuel production due to heavy metal resistance, great biomass and sugar enrichment in stem. However, the influence of heavy metals on sugar accumulation in sweet sorghum is still unknown. In this study, Cd induced modification of sugar storage and translocation in stem was monitored using two sweet sorghum cultivars Keller (KE) and E-tian (ET). Brix degree, which represents sugar content in stem juice, displays significant reduction in response to exogenous Cd treatment in both lines. The sugar enrichment is more obviously repressed in the lower internodes while it is hardly affected in the top internodes. Excessive Cd results in drastically enhanced Cd accumulation, preferentially in the lower internodes. More interestingly, negative correlation between Cd and sugar content is detected along internodes, indicating antagonistic translocation between Cd and sugar along stem of sweet sorghum. The preferential compartmentation of Cd and sugar in different regions of stem provides novel insights into understanding and application of sweet sorghum for combining biofuel production with phytoremediation of heavy metal in soil.

Abstract. Sweet sorghum ( (L.) Moench) is a multi-purpose crop, yielding fuel in the form of ethanol from its stem juice, food in the form of grain, and fodder from its leaves and bagasse. The sugars utilized for bioethanol production are contained in the stalks, in an amount varying between 12% and 25% of the fresh biomass, according to the genotypes and harvesting time. However, these carbohydrates can be easily lost during harvest and post-harvest, because of wrong machinery settings and prolonged periods of exposure of the cut material to the action of fermentative agents. For these reasons, the production of biofuel from sweet sorghum is very sensitive to harvest systems and storage methods, as they can influence remarkably the final energetic yield of the crop. The main objective of the present study was to monitor the time course of dry matter and sugar content in sweet sorghum stem over a long-time storage period. The analysis was carried out by dividing the stems into portions of different length in order to test different storage configuration by varying the stem portion stored to simulate the action of different harvest machines. This work has been designed to take into account a larger storage window respect previous experimentation. The research has provided evidence that sugar loss during the storage is highly influenced by the length of the stem portion, as well as by storage conditions. Total sugar content at harvest was on average 23.2%. The decreasing of sugar content continued during the storage period but at different rate for the different portions. At the end of storage, the sugar content of the whole stem was on average 6.6%, while the smallest portion (1/16 of the whole stem) had an average content of 1.0%. Indications on best storage conditions (storage form, storage location, storage ambient condition), as well as technical details regarding new potential harvesting solutions to decrease the speed rate of sugar loss have been provided. Keywords: Biofuel, Harvesting, Storage, Sugar losses, Sweet sorghum.

Estimation methods and parameter assessment for ethanol yields from total soluble solids of sweet sorghum

The use of biofuels helps to reduce the dependency on fossil fuels and therefore decreases CO2 emission. Ethanol mixed with gasoline in mandatory percentages has been used in many countries. However, production of ethanol mainly depends on food crops, commonly associated with problems such as governmental policies and social controversies. Sweet sorghum (Sorghum bicolor (L.) Moench) is one of the most potential and appropriate alternative crops for biofuel production because of its high biomass and sugar content, strong tolerance to environmental stress conditions and diseases, and wide adaptability to various soils and climates. The aim of this study was to select prospective varieties of sweet sorghum, optimum sowing times and densities to achieve high yields of ethanol production and to establish stable operational conditions in cultivating this crop. The summer-autumn cropping season combined with the sowing densities of 8.3–10.9 plant m−2 obtained the highest ethanol yield. Among cultivated locations, the soil with pH of 5.5 and contents of Al and Zn of 39.4 and 0.6 g kg−1, respectively, was the best condition to have an ethanol yield >5000 L ha−1. The pH ≥ 6.0 may be responsible for the significant reduction of zinc content in soils, which decreases both biomass of sweet sorghum and ethanol yield, while contents of N, P, K, organic carbon (OC) and cation exchange capacity (CEC), and Fe likely play no role. The cultivar 4A was the preferred candidate for ethanol production and resistant to pests and diseases, especially cut worm (Agrotis spp.).

Sweet sorghum productivity for biofuels under increased soil salinity and reduced irrigation

Family selection in sugarcane (Saccharum spp.), as practiced in Australia, was difficult to implement in South Africa because of the non-availability of mechanical harvesting and automatic weighing machines. This study explored the potential of evaluating cane yield of sugarcane families estimated using stalk number, stalk height, and stalk diameter as compared to individual seedling selection. Data for stalk number, stalk height, and stalk diameter were collected from Bruyns Hill and irrigated populations and analyzed using the Statistical Analysis System (SAS) to estimate variance components and best linear unbiased predictors (BLUP). A sample of 500 seedlings produced a significant association (r = 89, P < 0.0001) between actual and estimated cane yield. The results showed significant differences for cane yield among families. Family estimates of broad-sense heritability (H) and percent predicted gains (%Gs) were larger than for individual seedling selection. Elite families within populations were identified using BLUP. Data from four replications and 10 seedlings per plot were adequate for family evaluation.

Co-fermentation of hemicellulosic hydrolysates and starch from sweet sorghum by Clostridium acetobutylicum: A synergistic effect for butanol production