Maejo International Journal of Energy and Environmental Communication

Brassinosteroid-enhanced phytoremediation for a sustainable strategy for mitigating vanadium contamination in agricultural soils

Yanhua Li — 2024-09-29

Vanadium (V) contamination in soils, primarily from mining, industrial activities, and fossil fuel combustion, poses a significant ecological threat to plants, animals, and humans. While vanadium is an essential trace element in biological systems, excessive accumulation disrupts plant physiological processes, leading to oxidative stress, impaired growth, and reduced crop productivity. Brassinosteroids (BRs), a class of plant steroid hormones, have emerged as promising agents for mitigating heavy metal toxicity. This study explores the role of BRs, particularly 28-homobrassinolide (HBL) and 24- epibrassinolide (EBL), in alleviating vanadium stress in plants. BRs enhance plant tolerance by modulating antioxidant defense mechanisms, regulating metal uptake, and activating stress-related signaling pathways such as MAPK and NADPH oxidase pathways. Additionally, BRs stimulate the production of reactive oxygen species (ROS) at controlled levels, inducing stress-adaptive responses while preventing oxidative damage. This review discusses vanadium speciation, soil contamination levels, plant uptake mechanisms, and the potential of BRs in assisted phytoremediation strategies. Understanding the molecular and physiological interactions between BRs and vanadium toxicity will provide insights into developing sustainable agricultural practices for improving crop resilience in contaminated environments.

A comprehensive review of electric vehicle energy management techniques, optimizations, and controllers

P. Srinivasarao — 2024-10-04

The terrible impact of environmental pollution and the greatest deficiency of fossil fuels, the development of electric vehicles (EVs) are alternatives to minimize the greenhouse gas emission and protect the environmental circumstances. Since most of the EVs are driven by energy storage sources (ESS), numerous researchers have conducted many investigations to ascertain the potentiality of ESS-based EVs. Nonetheless, the demand of end users is to enhance the lifetime of battery and reduce the consumption of hydrogen. Hence, advanced and newly designed control strategies are required for enriching the efficiency of the EVs with energy management systems (EMS). This work presents a state-of-the-art of various types of vehicles including ICE type, hybrid EVs, and all types EVs. The EMS strategies such as battery, ultra-capacitor (UC), flywheel energy storage (FES), fuel-cell, and hybrid energy storages are addressed in this work. Furthermore, different types of optimization methods are highlighted for solving the limitations and improving the performance of EVs in future. Diverse control techniques namely, classical controllers, fuzzy logic controller (FLC), model predictive control (MPC), and operational mode/state machine. Finally, this article provides a thorough analysis of these studies and makes recommendations for new researchers on how to proceed with their study in the future.

Sustainable biobutanol production from Amorphophallus tuber starch via optimized ABE fermentation

Solaiyammal Pandi — 2024-12-28

This study examines Amorphophallus tuber starch as a renewable carbon substrate for batch fermentation of acetone, butanol and ethanol (ABE) using Clostridium acetobutylicum TISTR. Scientists examined spent yeast extract as a potential economic substitute for conventional yeast extract as a nitrogen source. Batch fermentation of C. acetobutylicum required analysis of essential process parameters such as substrate concentration and nitrogen source selection and carbon source type, and pH values. The utilization of gelatinized Amorphophallus tuber starch by C. acetobutylicum led to a total solvent output of 28.45 g/L under uncontrolled pH conditions, which is similar to the 30.51 g/L solvent concentration attained with glucose. The highest solvent yield was observed during pure fermentation of gelatinized starch because enzymatic pretreatment failed to boost production, but acidic hydrolysis reduced solvent levels by 22.66%. Acidic conditions at pH 5.5 supported maximum solvent concentration (32.13 g/L), but pH 5.25 produced the highest acetone levels (6.59 g/L). The fermentation process at pH values above six promoted acidogenic pathways while producing minimal solvent amounts. Total solvent production reached its highest level of 28.56 g/L when the initial starch concentration was set at 70 g/L, yet lower concentrations under 30 g/L resulted in acidogenic metabolism. Recycled brewer's yeast extract produced solvents at a level that matched the performance of regular yeast extract by reaching 18.46 g/L. The findings from this research show that Amorphophallus tuber starch can effectively produce biobutanol with nutrients derived from brewery waste operations while supporting sustainable manufacturing approaches based on bio-circular economy sources.

Lignocellulosic valorization of groundnut shells for bioethanol: Energy potential and techno-economic feasibility

Kshitija Tikhe — 2024-11-04

This study investigates optimized calcium oxide (CaO) alkaline pretreatment to create sustainable bioethanol production from groundnut shell waste while evaluating its physical and chemical properties alongside bioenergy capabilities. The versatile properties of groundnut shells obtained from agricultural residues include low moisture content (9.5% wet basis), together with high volatile matter (70.2%) as well as fixed carbon (18.1%), while maintaining low ash content (3.2%) which makes these shells suitable for thermal and biochemical conversions. Their lignocellulosic composition is 32.8% cellulose, 20.1% hemicellulose, and 27.4% lignin. CaO pretreatment at 2% w/v concentration led to improved biomass digestibility, which produced total sugars at 465.2 mg/g and reducing sugars at 297.4 mg/g from the material. Enzymatic hydrolysis of the pretreated biomass achieved an additional glucose concentration of 318.7 mg/g. When Saccharomyces cerevisiae fermented the hydrolysate for 120 hours, it produced 33.6 g/L of ethanol, representing 88% theoretical yield. The pretreatment and subsequent hydrolysis stages yielded reducing sugar recovery rates of 86.5% and 84.1%, respectively, and total sugar recovery rates of 91.6% and 88.3%. Groundnut shells provide a substantial promise as a renewable energy resource because they have a 17.2 MJ/kg heating value and 13.9 MJ energy potential per kilogram of dry biomass. The integrated approach demonstrates the technical viability of bioethanol production from groundnut shells while contributing to sustainable agricultural practices and waste management, and operating within low-carbon energy systems of the circular bioeconomy framework.

Integrated aquaculture wastewater treatment and biodiesel production using mixed algal consortia

Rajeswaran Ramaraj — 2024-10-26

This study investigates the feasibility of integrating the process of waste treatment into aquaculture facilities, and biodiesel production can be achieved using multiple algae species. A mixed consortium consisting of Anabaena sp., Chlorella sp., together with Oscillatoria sp., Oedogonium sp., and Scenedesmus sp., was grown in untreated aquaculture wastewater for 15 days alongside F/2 synthetic medium cultivation. The combined system outperformed by effectively eliminating total nitrogen by 90.5% and removing total phosphorus along with orthophosphate at 100% and achieving 91.1% and 76.8% removal of nitrate and nitrite, respectively. Biomass production reached 7.3 g/L during wastewater-based cultivation, which doubled the results obtained from the F/2 control. The wastewater-grown cells accumulated lipids corresponding to a weight fraction of 43.9%, which generated 3.20 g/L lipid production. After the transesterification process, biodiesel yield matched the lipid yield (3.20 g/L), which produced an 81% greater output than in synthetic media. Laboratory tests on fatty acid methyl ester (FAME) composition showed high levels of palmitic acid (C16:0) and oleic acid (C18:1) that met all international biodiesel specifications according to ASTM D6751 and EN 14214. The research verifies how mixed microalgal cultures promote simultaneous water purification with sustainable biodiesel outcomes. A unified method publishes bioeconomy circularity through the conversion of aquaculture wastewater into renewable energy materials while it improves both aquatic farming sustainability together with operational energy efficiency.

Advancing bioenergy sustainability through hydrogen nanobubble- enhanced anaerobic digestion of tobacco stalks for biogas production

Kamoldara Reansuwan — 2024-11-19

The rising demand for renewable energy, alongside environmental pressures from agricultural residue disposal, requires innovative bioconversion methods. This study evaluates how hydrogen nanobubble water (H₂-NBW) benefits the anaerobic digestion (AD) process of tobacco stalks, a widespread lignocellulosic residue type in northern Thailand. Testing of tobacco stalk AD was performed under mesophilic temperatures with AD dosages ranging from zero to 100 percent H₂-NBW. The experiment measured methane production, digestion kinetics, redox environment, and fiber degradation rates. The combination of H₂-NBW at a 60% concentration delivered the best performance by producing 262.1 ± 6.4 mL/g VS of methane with 88.2% methane content during the AD process. Laboratory measurements using kinetic models demonstrated higher methane production speeds and shorter time-to-initial-production stages when the H₂-NBW levels were between moderate and high values. The digestion performance benefits from increased hemicellulose and cellulose degradation along with a reduced crystallinity structure, combined with better pH and Oxidation-reduction potential (ORP) stability, as laboratory results show. This study shows that maintaining appropriate concentrations of H₂-NBW as a supplement will produce both excellent fuel gas properties and low-cost waste management potential. The research outcomes demonstrate favorable conditions for wider nanobubble-assisted AD applications, which can serve as a sustainable waste management approach for agriculture while contributing to global renewable energy targets.

Enhanced biocompatibility: A comparative approach on polyethylene glycol and zinc-incorporated hydrogels

Vaidhegi Kugarajah — 2024-09-23

With recent medical technology developments, hydrogels have gained vast interest due to their soft tissue-like mechanical properties, injectability, high water content, etc. Poly (ethylene glycol) (PEG) hydrogels are highly commendable due to their synthetic structure, tunable architecture, biocompatibility, and reproducibility. In the present research, zinc nanoparticles at various concentrations (0.025, 0.05, 0.075 wt%) were infused in PEG hydrogels to enable better biocompatibility. The prepared nanocomposites are evaluated for their morphological, functional, and structural characteristics compared to naïve PEG hydrogel. Antibacterial activity revealed that PEG + 0.075 wt% Zn exhibited the maximum zone of inhibition of 0.09 ± 0.2mm compared to plain hydrogel (0.02 ± 0.5 mm). Statistical analysis through independent T-test exhibited a statistical significance of the nanocomposite hydrogel with p= 0.001, (p<0.05) when tested with a G-power of 80%, 0.5 alpha error, and 95% confidence interval. The present research introduces novel PEG-Zn nanocomposite hydrogels and offers a future scope for bioengineering applications.

Valorization of banana frond juice for bioethanol production: Process efficiency and circular economy implications

Piyaphong Yongphet — 2024-12-04

This investigation evaluates the microbial conversion capacity of banana frond juice (BFJ) as an accessible lignocellulosic feedstock through Saccharomyces cerevisiae fermentation under the best possible operation conditions. Mechanical pressing of fresh banana fronds produced juice with a yield average of 0.33 ± 0.02 L/kg along with an initial total sugar content of 76.4 ± 2.8 g/L. The bioconversion of clarified BFJ occurred under batch fermentation conditions at pH 5.6 and 36°C using 10% v/v yeast inoculum for 120 hours while measuring ethanol production together with sugar consumption at 24-hour intervals. The fermentation process achieved total sugar depletion at 96 hours, resulting in an ethanol production of 45.75 ± 1.1 g/L, which delivered a yield of 0.33 g/g sugar and an efficiency of 64.7% compared to theoretical maximums. During the fermentation process, researchers achieved an average volumetric ethanol productivity level of 0.38 g/L·h. The yield results of BFJ fall within competition when compared to sugarcane juice, oil palm frond juice, and banana pseudostem hydrolysates, while also requiring few processing steps without enzymatic or chemical pretreatment (Legodi et al., 2021). Statistical data showed that sugar consumption is directly linked to ethanol production through a correlation level of R² = 0.987 (p < 0.01). Biofuel production benefits from the Flush rejects/consumes BFJ as a promising and inexpensive raw material. The incorporation of banana fruit juice as a sustainable biofuel feedstock becomes viable due to its simple preprocessing demands combined with advantageous fermentation behaviour and circular bioeconomic alignment.