Sorghum Stalk Research Articles

Sheet nanocomposites of sorghum stalk loaded with hydrated ferric oxide for Cu(Ⅱ) deep removal from water

Novel sheet porous nanocomposites were developed for Cu(II) deep removal form water utilizing waste crop stalks. Hydrated ferric oxide (HFO) was coated onto the surface of sorghum crop stalk (SCS) through a simple and cleaner impregnation-surface deposition method to fabricate the nanocomposite adsorbent SCS-HFO. BET, SEM-EDX, FTIR and XPS characterization proved that HFO with a particle size of 10–50 nm was successfully loaded on the sorghum stalk surface. High level of coexisting cations such as Na+, Mg2+ and Ca2+ in aqueous solution had little influence on the Cu2+ adsorption capacity, showing that SCS-HFO had excellent adsorption selectivity. The adsorption of Cu2+ onto SCS-HFO fitted to Langmuir isothermal model, and the adsorption process conformed to the quasi-secondary kinetics, which indicates that monolayer chemical adsorption is dominant. The fixed-bed column of SCS-HFO could effectively reduce the Cu2+ concentration in 6.8 L of simulated wastewater to less than 0.01 mg/L. The NaCl-NH3·H2O mixed solution can regenerate SCS-HFO, and the adsorption efficiency of SCS-HFO still reaches more than 90 % after multiple adsorption-desorption cycles, indicating good stability of the prepared material. This study successfully constructed and fabricated a green and cost-effective nanocomposite adsorbent based on agricultural waste.

Bernoulli Distillation System (BDS) for Bioethanol Sorghum Stalk Purification

Sorghum is a plant that produces syrup, forage and animal feed silage. The utilization of sorghum stalk as fuel oil (bioethanol) is an energy increasingly needed by the depletion of deposits of fossil fuel oil. Thus, tools and methods are needed to produce sorghum stem bioethanol, which has a certain purity level. This study aims to increase the purity of bioethanol from sorghum stems using the Bernoulli Distillation System (BDS) by experimentally testing the purification of sorghum stem bioethanol. In the bioethanol purification stage, heat transfer in the reactor and condenser was analyzed, and the performance of the ejector was analyzed with a vacuum pressure (-55 cmHg), temperature 71°C, test time of 1800, 3600, 5400 and 7200 seconds with a test material of 28% capacity 20 liters. The results of the analysis of the highest conduction heat transfer on the water jacket wall are 14757.72 Joules, the reactor tank is 962.1 Joules, the bottom of the reactor tank is 765.05 Joules and convection in the reactor fluid is 2.09 Joules. The highest heat transfer energy in the condenser is 72683.1 Joules. While the efficiency of the water jet ejector is 65.4%, the highest increase in bioethanol content is 51% in 3600 seconds, as much as 745 ml. The characteristics of the bioethanol obtained included a calorific value test of 1389.48 cal/gram, a viscosity of 1.02044, a flash point of 32.5°C, and a density of 0.934 g/cm3. Thus, the Bernoulli Distillation System’s purification process can increase bioethanol levels effectively and efficiently.

Sorghum bicolor L. Stalk Stiffness Is Marginally Affected by Time of Day under Field Conditions

This study sought to better understand how time of day (ToD) or turgor pressure might affect the flexural stiffness of sweet sorghum stalks and potentially regulate stalk lodging resistance. Stalk flexural stiffness measured across a 48 h period in 2019 showed a significant diurnal association with leaf water potential and stalk flexural stiffness. While the correlation between stalk flexural stiffness and this proxy for internal turgor status was statistically significant, it only accounted for roughly 2% of the overall variance in stiffness. Given that turgor status is a dynamic rather than fixed physiological variable like the cellular structure, these data suggest that internal turgor plays a small yet significant role in influencing the flexural stiffness of fully mature stalks prior to a stalk lodging event. The association was assessed at earlier developmental stages across three distinct cultivars and found not to be significant. Panicle weight and stalk basal weight, but not stalk Brix or water content, were found to be better predictors of stalk flexural stiffness than either ToD or turgor status. Observation across three cultivars and four distinct developmental stages ranging from the vegetative to the hard-dough stages suggests that stalk flexural stiffness changes significantly as a function of time. However, neither ToD nor turgor status appear to meaningfully contribute to observed variations in stalk flexural stiffness in either individual stalks or across larger populations. As turgor status was not found to meaningfully influence stalk strength or flexural stiffness at any developmental time point examined in any of the three sweet sorghum cultivars under study, turgor pressure likely offers only inconsequential contributions to the biomechanics underlying sweet sorghum stalk lodging resistance.

Effects of harvest height and time on hay yield and quality of some sweet sorghum and sorghum Sudangrass hybrid varieties.

This experiment was conducted in the Research and Application Field of Canakkale Onsekiz Mart University, Faculty of Agriculture, during the 2020 and 2021 summer period. The objective of this experiment was to determine the effects of different harvesting heights on forage yields and crude ash, fat, protein, and carbon and nitrogen content of leaves and stalks of sweet sorghum (SS) and sorghum sudangrass hybrid (SSH) cultivars. Nutri Honey and Nutrima varieties of SSH and the M81-E and Topper-76 varieties of SS were used in this study. The experiment was conducted using the randomized complete block design with four replications. The main plots each included two early and late varieties of SS and SSH cultivars, while the subplots were used to test different harvesting heights (30, 60, 90, 120, 150 cm) and physiological parameters of each crop. The results of this study showed that dry forage yields increased with plant growth, with the amount of forage produced at the end of the growth cycle increasing 172.2% compared to the early growth stages. Carbon (C) content of leaves decreased by 6.5%, nitrogen (N) by 46%, crude protein (CP) by 54%, crude fat (CF) by 34%, while crude ash (CA) content increased by 6% due to the increase in plant height harvest. At the same time, in parallel with the increase in plant height at harvest, the nitrogen content of the stems of the plants decreased by 87%, crude protein by 65%, crude ash by 33% and crude fat by 41%, while the carbon content increased by 4%. As plant height at harvest increased, hay yield increased but nutrient contents of the hay decreased. However, the Nutrima, Nutri Honey and M81-E sorghum cultivars, harvested three times at heights of 90 to 120 cm, are recommended for the highest yield.

Analysis of the Management of Cereal Crop Residues on Farms to Optimise Cattle Feed in the Western Cotton Growing Zone of Burkina Faso

Crop residues are insufficiently valorised by farmers in western Burkina Faso, while cattle face a shortage of forage. The aim of this study was to analyse the management of cereal crop residues in cotton-cereal farming to optimise their use as feed for draught cattle. A sample of 72 cotton farmers was selected from nine villages in the study area by the stratification method and interviewed using a semi-structured questionnaire. The quantities of cereal crop residue biomass collected by farmers were assessed directly in the field. The results showed that maize and sorghum stalks were predominantly used in cattle feed (86.1 and 90.3%), composting (50 and 44.4%), and mulching (26.9 and 25%), respectively. The average quantities of cereal crop residues stored were 0.83, 0.16, and 1.19 tonnes of dry matter (tDM) for crop farmers, livestock breeders, and agro-pastoralists, respectively, with respective fodder balances of -3.99, -29.05, and -16.99 Tropical Cattle Units (TCU) for the use of cattle, or -0.88, -0.38, and -1.81 TCU for the use of draught cattle during the lean season. Concentrated feed use was 0.20, 0.05, and 0.21 kg/cattle/day; respectively. The main factors influencing the quantities of cereal residues stored on the farms were the size of the cultivated areas and the farmers’ capacity for transportation. Provision of transport equipment and storage infrastructure would therefore appear to be a solution that could improve the level of fodder residue storage, particularly for draught oxen.

Biomass C-doped three-dimensional Bi2WO6 for enhanced visible-light-driven photodegradation of diclofenac and rhodamine B

Photocatalysis as a green and efficient pollutant degradation technology, displaying great potential in environmental purification. By one step hydrothermal method in this study, flower-like Bi2WO6 with a large specific surface area was obtained, and the preparation of biomass carbon modified Bi2WO6 with sorghum stalks was also proposed to construct a series (BWO/x%C). The composites were effectively characterized in terms of several aspects of structure and properties. With the dyes rhodamine B and diclofenac as typical organic pollutants, the photocatalytic activity of the proposed photocatalysts was evaluated. Under visible light irradiation, the removal of rhodamine B by BWO/4%C reached 97.27% within 50 min and that of diclofenac reached 96.19% within 120 min, which were significantly favorable to single-phase Bi2WO6. The superiority of this system BWO/4%C is mainly due to its large specific surface area (33.51 m2/g), which provides additional reaction sites for contaminants. The UV–Vis DRS findings indicated that the modified biomass C reduced the band gap of Bi2WO6 and improved the availability of Bi2WO6 to visible light, and the separation efficiency of the electron and hole pairs of Bi2WO6 was improved due to the strong electron transfer ability of biomass C. The analyzing results of free radical trapping experiments confirmed that h+ and •O2- are the main active substances involved in the photodegradation reaction. The results of five cycle experiments exhibited that the degradation rate of rhodamine B still reached higher than 90%, confirming the good stability of the prepared material. Finally, a feasible degradation mechanism was proposed for the degradation of rhodamine B and diclofenac. It offers new ideas for the development of composite nano-photocatalytic materials targeting difficult-to-degrade organic pollutants.

Study on Structural and Morphological of Steam-Treated Sorghum Stalk Fiber: Enhancing Potential for Reinforcement in Polymer Composite

Lignocellulosic biomass, such as sorghum stalk fiber, has received a lot of interest as reinforcement in polymer composites because of its renewable nature, low cost, and potential environmental benefits. This is due to crystalline cellulose fibrils embedded in hemicellulose, lignin, wax, and other impurities in the lignocellulosic fiber. As a result, treatment to remove non-cellulosic components, expose cellulose fibrils, and improve the adhesion with polymer matrices is critical for their usage as reinforcement in polymer composites. This study investigates the effects of environmentally friendly steam treatment on sorghum stalk fiber's structural and morphological properties. Sorghum stalk fiber was subjected to steam treatment conditions at different durations. Fourier transform infrared (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and sessile drop tests were used to examine the structural and morphological changes generated by steam treatment. It was observed that the steam treatment of sorghum fiber was successful in eliminating part of the amorphous lignin and hemicellulose components as well as contaminants such as wax, causing the crystallinity ratio to rise. Defibrillation also occurs, and the fiber surface becomes rougher. Due to the rough fiber surface and the space created by defibrillation, the polymer matrix can penetrate the fiber and increase its adhesion by a mechanical interlocking mechanism.

Comparative Analysis of Macro/Microstructures and Constituents of Sorghum and Reed Straw.

Node-containing straws exhibit superior mechanical properties compared to node-free straw plants, particularly in terms of shear resistance and compression resistance. We explore the relationship between the structure and mechanical properties of straw materials, providing deeper insights for the field of biomechanics. In this study, we focused on two node-containing straw plants, namely sorghum and reed. The main characteristics of sorghum and reed stalks were compared using macroscopic observation, stereomicroscopy, scanning electron microscopy, infrared spectroscopy, and EDS analysis. This study revealed numerous similarities and differences in the macro- and microstructures as well as the elemental composition of sorghum and reed stalks. The functional groups in sorghum and reed stalks were largely similar, with the primary elements being C and O. Distinguishing features included a higher tapering and a slightly larger reduction in wall thickness in sorghum stalks compared to reed stalks. The cross-section of sorghum stalks was filled with pith structures, while reed stalks exhibited a hollow structure. The vascular bundles in sorghum typically showed a paired arrangement, whereas those in reeds were arranged in odd numbers. Furthermore, sorghum straws contained more Cl and no Br, while the parenchyma of reed straws contained higher Br. The C and O proportions of sorghum straws and reed straws are 50-53% (50-51%) and 45-46% (48-49%), respectively. These variations in elemental composition are believed to be correlated with the mechanical properties of the materials. By conducting a detailed study of the micro/macrostructures and material composition of sorghum and reed straw, this paper provides valuable insights for the field of biomechanics.

Hydrogen and Fatty Acid Production by Dark Fermentation of Sweet Sorghum Stalks as an Efficient Pre-treatment for Energy Recovery Before Their Bioconversion into Methane

Hydrogen and Fatty Acid Production by Dark Fermentation of Sweet Sorghum Stalks as an Efficient Pre-treatment for Energy Recovery Before Their Bioconversion into Methane

Differences in Chemical Composition, Polyphenol Compounds, Antioxidant Activity, and In Vitro Rumen Fermentation among Sorghum Stalks

The aim of the study was to examine the differences in the chemical composition, polyphenol compounds, antioxidant activity, and in vitro rumen fermentation among six varieties of sorghum stalks. The results show that maoliangnuo 1 (M1) contained a higher (p < 0.05) level of dry matter, and jinzhong 405 (J4) contained a higher (p < 0.05) level of crude protein content. The concentrations of neutral detergent fiber, acid detergent fiber, and cellulose were significantly higher (p < 0.05) in stalk jinliangnuo (JN). The levels of chlorogenic acid, homoorientin, isovitexin, vitexin, rhoifolin, genistin, quercetin, apigenin, aloe emodin, emodin, and total polyphenols were all significantly (p < 0.05) higher in maohongnuo 6 (M6) than in the other stalks. Moreover, stalk M6 contained higher (p < 0.05) levels of total antioxidant capacity (TAC), glutathione peroxidase (GPX), catalase (CAT), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging capacity. There were significant (p < 0.05) positive correlations between total polyphenols and TAC, superoxide dismutase, GPX, CAT, and DPPH free-radical scavenging capacity. The total gas production was significantly (p < 0.05) influenced by the sorghum stalk variety and incubation time. Stalk J4 displayed higher values for the (p < 0.05) immediately soluble fraction and the potential extent of gas production, while stalk M6 exhibited a significantly lower (p < 0.05) insoluble fraction level. Furthermore, stalk M6 exhibited a significantly higher level of (p < 0.05) ruminal fluid propionic acid, but its level of butyric acid and its ratio of acetic acid to propionic acid were both significantly lower (p < 0.05). Taken together, the results reported in this paper indicate that the chemical composition, polyphenol compounds, antioxidant activity, and in vitro rumen fermentation all vary greatly among different varieties of sorghum stalks.

Lodging Variability in Sorghum Stalks Is Dependent on the Biomechanical and Chemical Composition of the Stalk Rinds

Stalk lodging contributes to significant crop yield losses. Therefore, understanding the biomechanical strength and structural rigidity of grain stalks can contribute to improving stalk lodging resistance in crops. From the structural constituents of the stalk, the rind provides the principal structure, supporting cells against tension and bending loads. In this work, the biomechanical and viscoelastic behavior of the rind from the internodes of two sweet sorghum varieties (Della and REDforGREEN (RG)), grown in two different growing seasons, were evaluated by three-point micro-bending tests using a dynamic mechanical analyzer (DMA). In addition, the chemical composition of rinds and the microfibril angle (MFA) of the cell wall were determined using XRD. The results revealed that the biomechanical behavior of Della varieties was stiffer and more resistant to loads than that of RG varieties. Two features of the rind biomechanical properties, flexural modulus (FM) and flexural strength (FS), showed a significant reduction for RG. Particularly, a reduction in FS of 16–37% and in FM of 22–41% were detected for RG1. Changes in the stalks’ rind biomechanical properties were attributed to cell wall components. Total lignin and glucan/cellulose contents were positively correlated with the FM and FS of the rind. Subsequently, an increase in the two cell wall components drove an increase in stiffness. Furthermore, the MFA of the rind was also found to influence the rind strength.

ANIMAL FEED PACKAGING INNOVATION MADE FROM GREEN SORGUM TO REDUCE PRODUCT DAMAGE IN THE STORAGE PROCESS

Silage as a feed ingredient for ruminants is very helpful for farmers in fulfil need feed . Traditional breeders who are only able to raise livestock on the side cannot earn money decent income. Livestock must always innovate in making animal feed so that they do not depend on looking for grass every day. Making silage as animal feed can help sustainable livestock farming. Community service was carried out in Weling Hamlet RT03/04 Cibuluh Village, Ujungjaya District, Sumedang Regency. Training on making silage was carried out with farmer groups, with processing the main ingredient being sorghum stalks . At the moment Still there is goods produced too Many NGs are caused by biting mice plastic resulting packaging holes in plastic packaging .NG caused Can reached 15% of capacity stored production at warehouse. Done repair packaging with use a plastic drum so free from bite mice on packaging at a time repair quality nutrition . In improving Sorghum tree nutrients are chopped using a cupper machine , then mixed with bran, molasses, groats, stirred and packaged using plastic drums. Making airtight silage ensures that outside air does not enter, because if the material is contaminated with outside air it will become damaged and moldy.

Biomass-derived 3D evaporator with antifouling and salt-rejecting toward solar-enabled steam generation, desalination, and electricity generation

Solar-driven interfacial evaporation is currently considered as one of the most effective and sustainable strategies to address water scarcity and energy shortages issues. Whereas, challenges in developing durable, eco-friendly, and low-cost solar evaporators from readily available materials still exist. Herein, we have reported a facile strategy to construct a robust natural sorghum stalk pith solar evaporator. With advantageous features of gradient honeycomb structure and hydrophilic polymer chains, the constructed evaporator exhibits broadband light absorption, efficient light to heat conversion, fast water transport, and multi-channel release of steam performances, leading to an ultrahigh evaporation rate of 3.79 kg m−2h−1 under one sun irradiation and outstanding salt-resistant ability at a high evaporation rate of 2.6 kg·m−2·h−1 in a highly concentrated brine (20 wt% NaCl), accompanied with anti-oil-fouling performances, as well as high oil removal efficiency (>99.8 %) for oil-in-water emulsion, outperforming most previously reported solar evaporators. Additionally, solar irradiation can further promote the directional water flow, contributing to a high photovoltage of 68 mV under one sun illumination. This paves the way for designing durable biomass-based steam generators, not only scaling up sustainable clean water production, sewage depuration and desalination, but also discovering promising application in the field of electricity generation.

Dissolved black carbon mediated photo-oxidation of arsenic(III) to arsenic(V) in water: The key role of triplet states

Arsenic is a common contaminant found in natural waters, and has raised significant environmental concerns due to its toxicity and carcinogenicity. In this study, we investigated the mediated photo-oxidation of arsenite (As(III)) under simulated sunlight by dissolved black carbon (DBC), an important dissolved organic matter (DOM) constituent released from black carbon. Five DBC were collected from the water extracts of black carbons that were derived by pyrolyzing different biomass (i.e., bamboo, rice, peanuts, corn, and sorghum stalks), and four well-studied dissolved humic substances (DHS) were selected for benchmarking. The presence of DBC (i.e., 5 mg C−1) significantly accelerated the photo-oxidation of As(III) to arsenate (As(V)), with the observed pseudo-first-order rate constant of reaction increased by 5∼11 times. Quenching experiments of photochemically produced reactive intermediates suggested that As(III) was mainly oxidized by triplet-excited DBC (3DBC*, contribution of 48%), singlet oxygen (1O2, 18%) and superoxide anions (O2•-, 28%) in sunlight-irradiated DBC solutions. The average apparent quantum yield of As(III) photo-oxidation for DBC was found to be more than 4 times higher in comparison with DHS. Such a strong mediation efficiency of DBC was due to its smaller molecular size and higher aromaticity than DHS, which facilitated the non-charge-transfer process to produce triplet-excited states and their sensitized 1O2. Consistently, DBC exhibited a higher apparent quantum yield and a longer lifetime of triplet states as compared with DHS. The results imply that DBC may play a previously unrecognized important role in the fate of arsenic in aquatic environments.

A comprehensive pyrolysis study of sorghum and reed stalk: TG/IR/MS analysis and machine learning-assisted kinetic prediction

This work focused on investigating the pyrolysis characteristics of sorghum stalk (SS) and reed stalk (RS), whose potentiality as value-added feedstocks for thermochemical conversion is largely unexplored. The experimental method, thermogravimetric-infrared-mass spectrometry, was applied to reveal the thermal decomposition process, evaluate the kinetic and thermodynamic parameters, and identify the gaseous products, which could provide fundamental data and valuable information for bioenergy utilization and optimization of reactors. The average activation energy values of SS and RS by isoconversional methods are estimated to be 185.0–210.4 kJ/mol and 192.6–197.0 kJ/mol. Though kinetic parameters, especially activation energy values, play a crucial role in understanding reaction mechanism and guiding further applications, conventional methods are time-consuming and labor-intensive. In the current work, a gradient boosting regression tree model was successfully constructed to achieve fast prediction of activation energy values with a competitive accuracy of R2 > 0.85 without repetitive experiments. In addition, the established model has showed good generalization ability in new datasets, which reveals the great potential of the machine learning approach in the pyrolysis kinetic field.

Impact of Mechanical Stirring and Percolate Recirculation on the Performances of Dry Anaerobic Digestion

Dry anaerobic digestion (DAD) is an attractive method for simultaneous organic waste disposal and bioenergy recovery. DAD has the problems of low methane yields, low reaction rates, and easy inhibition due to its limited mass transfer and heat transfer. In this work, two methods of mechanical stirring and percolate recirculation were compared regarding their capacities of improving the mass transfer and enhancing the performances of DAD in batch experiments with sorghum stalks as a substrate. The cumulative biogas yield and system stability were investigated when the stirring linear velocity was 0 cm/s, 22 cm/s, 44 cm/s, 66 cm/s, and 88 cm/s. When the stirring linear velocity was 88 cm/s, the cumulative biogas yield and methane content were highest. The computational fluid dynamics (CFD) simulation indicated that the shearing force near the stirring shaft was largest. When the linear velocity of the stirring paddle was 88 cm/s, the shearing force at a radial distance close to center was about −140 N/m2. When the ratio of the material stacking height to the reactor diameter (H/D) was 3:2, the AD showed the best performance. A higher material stacking height promoted the contact between the microorganisms and the substrate and enhanced the biogas production. By combining percolate recirculation and mechanical stirring, the cumulative biogas yield increased by 28% compared with the static DAD process because of the promotion of mass transfer in the DAD.

Development of sustainable biomass residues for biofuels applications

A comprehensive understanding of physiochemical properties, thermal degradation behavior and chemical composition is significant for biomass residues before their thermochemical conversion for energy production. In this investigation, teff straw (TS), coffee husk (CH), corn cob (CC), and sweet sorghum stalk (SSS) residues were characterized to assess their potential applications as value-added bioenergy and chemical products. The thermal degradation behavior of CC, CH, TS and SSS samples is calculated using four different heating rates. The activation energy values ranged from 81.919 to 262.238 and 85.737–212.349 kJ mol−1 and were generated by the KAS and FWO models and aided in understanding the biomass conversion process into bio-products. The cellulose, hemicellulose, and lignin contents of CC, CH, TS, and SSS were found to be in the ranges of 31.56–41.15%, 23.9–32.02%, and 19.85–25.07%, respectively. The calorific values of the residues ranged from 17.3 to 19.7 MJ/kg, comparable to crude biomass. Scanning electron micrographs revealed agglomerated, irregular, and rough textures, with parallel lines providing nutrient and water transport pathways in all biomass samples. Energy Dispersive X-ray spectra and X-ray diffraction analysis indicated the presence of high carbonaceous material and crystalline nature. FTIR analysis identified prominent band peaks at specific wave numbers. Based on these findings, it can be concluded that these residues hold potential as energy sources for various applications, such as the textile, plastics, paints, automobile, and food additive industries.

The Conversion of Sorghum (Sorghum bicolor (L.) Moench) Stem Waste into Activated Carbon by the Pyrolysis Method Using ZnCl2 Activator

<p><strong>Abstract.</strong> The use of activated carbon in Indonesia is expanding along with the increasing demand for activated carbon. Therefore, it is necessary to continue to search for raw materials and methods for producing activated carbon to produce high-quality activated carbon. Sorghum stalk (Sorghum bicolor (L.) Moench) is used as a new precursor for the formation of activated carbon by utilizing a ZnCl<sub>2</sub> activator followed by pyrolysis in a furnace with a temperature of 800°C. This study aims to determine the effect of drying and the concentration of activator agents on activated carbon production. The ZnCl<sub>2</sub> activator concentrations used were 15% and 30%. The results showed that the activated carbon obtained through the withdrawal process with a ZnCl<sub>2</sub> concentration of 30% had the highest carbon content, namely 100%. Test results with FTIR spectroscopy showed that the activated carbon samples had groups (C-H), (O-H), (C≡C), (C=O), (C=C), and (C-O). In addition, the SEM test results showed that the surface of the activated carbon formed had many pores. With the presence of activated carbon from sorghum stem waste, it is hoped that this product can reduce the contaminants contained in wastewater.</p><p><strong>Keywords: </strong></p><p><strong></strong>Activation, Activated Carbon, Waste, Pyrolysis, Sorghum, ZnCl<sub>2</sub></p>

Engineering Thermoanaerobacterium aotearoense SCUT27 with the deficiency of a hypothetic protein regulated by ArgR1864 for enhanced ethanol production from lignocellulosic hydrolysates

Arginine repressor (ArgR1864) is a multifunctional regulator in Thermoanaerobacterium aotearoense SCUT27 (SCUT27). For better understanding its function in SCUT27, the transcriptome of SCUT27/ΔargR1864 under xylose was further investigated. 2014 (V518_2014) denoted as a hypothetic protein gene was mined, which played important roles on xylose metabolism and carbon metabolic flux distribution in SCUT27. In 2014 deletion mutant, no lactic acid could be produced along with enhanced ethanol formation. Same changes were also observed in SCUT27/ΔargR1864. ArgR1864 is the direct regulator of 2014 identified by electrophoretic mobility shift assays (EMSA). When 2014 was complemented in SCUT27/ΔargR1864, the fermentation traits of SCUT27/ΔargR1864/2014 were returned to wild-type levels, suggesting that the improved xylose utilization and ethanol formation of SCUT27/ΔargR1864 were attributed to the low expression of 2014. When cultured under sorghum stalk, corn cob and wheat straw hydrolysates, SCUT27/Δ2014 also showed the excellent capability for sugar utilization and ethanol production with the consumption rate of xylose and glucose increased by 20%–37.93 and 64.29%–190.91% separately, the ethanol production improved by 326.61%–547.89% and ethanol yield enhanced by 216.67%–337.50%. Thus, 2014, as a hypothetic protein gene, could be used as the new genetic reference to predict functional genes to engineer the microorganism for biofuel production from lignocellulosic hydrolysates.

Effect of using different clarifying agents and temperature on physicochemical and sensory properties of sweet sorghum syrup extract

The utilization of sorghum crops to produce value-added products such as alternative natural sweeteners has been increasing. Knowledge of the sweet sorghum juice clarification process to yield sweet sorghum syrup as an alternative sweetener is essential to get the best result and improve the quality of the syrup. This research aimed to study the sorghum syrup extraction process by using clarifying agents: Ca(OH)2, bentonite, and activated carbon, followed by the heating process at 70oC or 80oC. Sorghum stalks were milled to produce sorghum juice then clarified and heated up to make sweet sorghum syrup to reach 68.78-76.78% Bx. The clarification process was done to reduce particles in sorghum juice before the heating process. In this work, the psycho-chemical (pH, colour, turbidity, reducing sugar) and sensory properties (flavour and aroma) of sorghum syrup after clarification and heating process were analyzed. A randomized block design was used as the experimental design. Adding Ca(OH)2 and heating at 80oC resulted in sorghum syrup with higher pH and lower turbidity than that heated at 70oC. The evaluation revealed that the combination of Ca(OH)2 and 5% bentonite has the sweetest flavour, caramel aroma, and preferred psycho-chemical properties showed in pH (5.28), turbidity (35.56 NTU), and reducing sugar (57.52%).