This study utilized a circular economy approach to convert unripe rice, a low-cost by-product of the rice milling industry, into biofuels using a biorefinery process. The recombinant yeast Saccharomyces cerevisiae ER T12.7 strain was tested for its ability to produce ethanol from unripe rice. In hydrolysis trials with 20 % (dw/v) UR, ER T12.7 showed superior saccharification yields comparable to the commercial enzyme STARGEN 002. In 1-L bioreactor tests, ER T12.7 produced ethanol as efficiently as the parental ER V1 strain under simultaneous saccharification and fermentation. The spent fermentation broth from both amylolytic strains was evaluated for biomethane production, achieving high yields of up to 373.61 mL CH/g volatile solids. This research is the first to demonstrate process integration to produce ethanol and methane from rice waste sequentially, highlighting the potential of unripe rice in biorefining for a circular economy.

Fungi are emerging as key organisms in tackling global challenges related to agricultural and food productivity, environmental sustainability, and climate change. This review delves into the transformative potential of fungal genomics and metabolic engineering, two forefront fields in modern biotechnology. Fungal genomics entails the thorough analysis and manipulation of fungal genetic material to enhance desirable traits, such as pest resistance, nutrient absorption, and stress tolerance. Metabolic engineering focuses on altering the biochemical pathways within fungi to optimize the production of valuable compounds, including biofuels, pharmaceuticals, and industrial enzymes. By artificial intelligence (AI)-driven integration of genetic and metabolic engineering techniques, we can harness the unique capabilities of both filamentous and mycorrhizal fungi to develop sustainable agricultural practices, enhance soil health, and promote ecosystem restoration. This review explores the current state of research, technological advancements, and practical applications, offering insights into scalability challenges on how integrative fungal genomics and metabolic engineering can deliver innovative solutions for a sustainable future.

Severe membrane fouling and low CH content in the produced biogas have restricted the applicability and energy recovery profit of the anaerobic membrane bioreactor (AnMBR). Herein, a novel AnMBR was constructed with an electrochemical hydrogen evolution reaction (electro-HER) by double anodes and a titanium membrane-cathode (eHAnMBR). The electro-HER was controlled and enhanced by sacrificed iron anode under low voltage, to mitigate membrane fouling and upgrade biogas simultaneously. The critical factors in electro-HER were investigated to influence the AnMBR system, including hydrogen, applied voltage, and Fe ions. The voltage and hydrogen enhanced the hydrogenotrophic methanogenesis process and enriched hydrophilic Methanobacterium and Methanosarcina, thereby improving biogas purity by up to 28% and increasing total CH₄ production by 46%. Furthermore, the electro-HER on the membrane-cathode decreased the transmembrane pressure by 30%. Time of Flight Secondary Ion Mass Spectrometry (TOF-SIMs) was innovatively applied to visualize the organic foulants in membrane pores. The electro-HER not only produced H to optimize cake layer structure but also produced local alkalinity on the membrane surface, to remove extracellular polymeric substances in membrane pores. Additionally, Fe/Fe released from the sacrificial iron anode, facilitated phosphate precipitation and removal from 15.7% to 37.9%. This study presents a novel and sustainable wastewater treatment solution by integrating the electro-HER process with AnMBR, enabling both energy recovery and membrane antifouling.

This study examined hydrogen conversion efficiency and operational stability in pilot-scale in-situ bio-methanation during the co-digestion of sewage sludge and lactic acid (partially derived from waste poly-lactic acid). Parallel laboratory-scale experiments were also conducted. In the pilot, hydrogen conversion efficiency decreased from 98.9 % to 84.4 % as the hydrogen feed rate increased from 240 to 1,200 mL/L/d. Conversely, laboratory experiments maintained efficiencies above 95 % at a feed rate of 3,600 mL/L/d, suggesting that hydrogen gas-liquid transfer limited hydrogen conversion efficiency in the pilot. Lactic acid degradation was observed both with and without hydrogen injection in the pilot. Methane yields from the acid were 310 ± 30 and 300 ± 30 mL/g (chemical oxygen demand (COD))-added, close to the theoretical methane yield (350 mL/gCOD). These results demonstrate the importance of hydrogen gas-liquid transfer when scaling up bio-methanation processes. Moreover, they showed the potential of waste poly-lactic acid as a methane source.

Leveraging biofuel derived from biomass stands as a pivotal strategy in reducing CO emissions and mitigating the greenhouse effect. Biomass serves as a clean, renewable energy source, offering inherent benefits. However, despite its advantages, biomass encounters obstacles hindering its widespread industrial applications, including its relatively low calorific value, limited grindability, high water content, and susceptibility to corrosion. The torrefaction process has garnered significant attention as an effective method for enhancing the quality of raw biomass for energy production. In this review, we briefly discussed the mechanism of bio-coal preparation using biomass, physico-chemical characterization of different torrefied feedstocks, and the effect of torrefaction parameters, along with the effect of the different types of reactors on biomass torrefaction. Furthermore, bio-coal's emission characteristics and fuel quality throughout the thermal treatment have been covered. Thus, bio-coal finds a wide range of applications in sustainable energy generation, environmental remediation, agri-food development, polymer composites, and others.

This study investigates the enhancement of methane production in anaerobic co-digestion (AcoD) through the introduction of exogenous CO₂ and the application of bamboo biochar. Exogenous CO₂ boosts biogas yield by providing an additional carbon source, which requires optimized solubility and pH buffering to ensure effective methanation. Biochar serves as an electron shuttle and pH stabilizer, facilitating CO solubility and syntrophic interactions that enhance microbial stability. When combined, biochar and CO₂ (R2) achieved a significant synergistic effect, increasing specific methane production (SMP) by 42.56% compared to the control (R0). Independent additions of biochar (R1) and CO₂ (R3) also improved SMP, with increases of 35.50% and 28.01%, respectively. This enhancement is likely due to the elevated activity of homoacetogenic bacteria and hydrogenotrophic methanogens, with increased acsB gene expression 2.4-fold with biochar + CO₂ and 1.5-fold with CO₂ alone compared to the control. Additionally, biochar facilitated syntrophic metabolism mediated by Cytochrome-C, promoting electron transfer. The study also demonstrated that biochar and CO could enhance enzyme activity, including acetyl-CoA synthase, mhpF, and mhpE. Such improvements bolster AcoD efficiency and promote resource recycling within the circular economy framework.

The development of new measurement methods to assess fugitive methane (CH) emissions from industrial sources is needed to improve our understanding of these emissions and promote mitigation practices. Drone-based measurement methods have rapidly emerged in the last few years, however, there are still challenges in finding accurate drone-based measurement approaches and assessing their suitability. This study aims to validate and demonstrate a drone-based method that simultaneously measures atmospheric gas concentrations and wind vectors while flying downwind of the emission source. During the development phase, several tests were performed to ensure that the wind sensor was placed avoiding the majority of downwash and backwash interference. Comparing wind measurements taken at two wind masts and on a mast and a drone produced similar results, thus supporting the reliability of drone-based wind measurements. Moreover, the drone flux method (DFM) was validated by quantifying CH emissions from controlled release tests (2.18 or 3.59 kg h) and the release mimicked (1) a ground-based single source, (2) a ground-based double source and (3) an elevated single source. The DFM results had error rates ranging from +33 to -35%. The DFM was further used to assess emissions from a biogas plant, with simultaneous measurements using the tracer gas dispersion method (TDM). During the same time interval, the DFM quantified the biogas plant emitting CH at a rate of 25.3 ± 6.2 kg h, while the TDM averaged 25.7 ± 4.4 kg h. The method expanded uncertainty (95% confidence interval) assessment was 46% for the controlled release test for single flights quantification. By increasing the number of flights, the uncertainty theoretically decreased to 33% and to 27% for averages of 2 or 3 flights, respectively. Wind sensitivity analysis revealed the importance of assessing wind speed reliably, considering the measured plume height and atmospheric conditions; otherwise, significant errors in the emission determination can occur.

Surfactant is generally regarded to enhance the hydrolysis rate and favor high efficiency which however has not been revealed in the lignocellulosic anaerobic co-digestion process. In particular, the responses and functions of fungal community exposing to surfactants remain largely unknown. In this study, the roles of dodecyl dimethyl benzyl ammonium chloride (DDBAC, cationic), linear alkylbenzene sulfonate (LAS, anionic) and Triton X-100 (TX, nonionic) surfactants on the lignocellulosic anaerobic co-digestion were investigated. 1 mg/L DDBAC, LAS and TX promoted the degradation of lignocellulose and increased biogas yields by 6.85%, 62.76% and 36.96% comparing with the control group (CK). LAS and TX stimulated the growth of Prevotella, Petrimonas and Romboutsia, produced higher activities of cellulase (averagely 4.22 and 3.73 times of CK), generated more volatile fatty acids (VFAs, averagely 2.94 and 2.44 times of CK) and NH-N (averagely 1.91 and 1.63 times of the control group), and finally realized efficient acetoclastic methanogenesis. The abundant fungi genera, Pseudallescheria, Pseudeurotium, Monascus and Aspergillus were significantly correlated to lignin, cellulose, VFAs, ammonia nitrogen (NH-N), cellulase and coenzyme F activities (p < 0.05). Surfactants exposure damaged the connectivity of Proteobacteria with other microbes in the co-occurrence networks while increased the connectivity of Ascomycota to offset the disturbance of surfactants on the fungal community. The synergistic interaction between bacteria and fungi achieved efficient substrate degradation, contributed to the stability of microbial community and resulted in high biogas production. This research provided references for further management of surfactants exposed lignocellulosic anaerobic co-digestion process and systematically biowaste treatment in large-scale farms.

The study evaluates the effectiveness of aged refuse bioreactors (ARBs) in treating young landfill leachate and recovering energy through biogas production. Over 90 days, duplicate reactors (ARB1 and ARB2) were operated through three 30-day recirculation cycles under anaerobic conditions, utilizing aged refuse from a closed landfill in Bangalore, India. The study was extended by an additional 900 days without further leachate addition to assess long-term gas generation potential. Cumulative gas production amounted to 1384 L in ARB1 and 1182 L in ARB2, with maximum methane production per gram of chemical oxygen demand (COD) recorded at 0.474 L and 0.387 L, respectively. Variability in biogas production was correlated with differences in volumetric moisture content, which also influenced pollutant removal and led to significant improvements in the leachate pollution index, decreasing from 24.4 to 12.84 in ARB1 and to 16.46 in ARB2. COD levels were decreased by 70-90%, and TDS by 46-63%. Heavy metal concentrations, including copper, chromium, cadmium, lead, zinc, and nickel, were reduced by 95-99% to acceptable levels, though increases in ammonia and total phosphorus were noted. Key mechanisms in the ARB included anaerobic degradation, adsorption, oxidation-reduction reactions, and precipitation. In the fourth cycle, without leachate recirculation, gas production reached 320 L in ARB1 and 358.8 L in ARB2, indicating effective conversion of carbon retained from aged refuse and leachate treatment into biogas. Microbial analysis identified dominant communities of Methanosarcina and Methanomicrobia. Overall, this study demonstrates that ARBs are effective in treating young landfill leachate and recovering energy, offering insights into sustainable waste management.

This article examines the development of Ukraine's liquid biofuels market, driven by the need to diversify its fuel supply amidst complete reliance on imported fuels for road transport. The country also faces challenges exporting agricultural feedstock for first-generation biofuels due to geopolitical disruptions since early 2022. In response, the production and use of liquid biofuels represent a strategic move to reduce dependence on fossil fuels while fulfilling international obligations, including the ones within the Energy Community and the European Union (EU). Ukraine must align with the EU's renewable energy targets as a candidate for EU accession. Using the methods of fuel consumption quantification, blending mandate assessment, and excise tax rate calculation framework, the article finds that the potential market demand for bioethanol in Ukraine is projected to range from 125 to 278 thousand tonnes and for biodiesel from 196 to 431 thousand tonnes in 2025-2031. Ukraine's biofuel production potential could reach 2.54 million tonnes of oil equivalent by 2050, with advanced biofuels expected to dominate. Current excise tax rates for bioethanol are considered appropriate and supportive of market growth. To foster further development, legislative amendments are needed to mandate biodiesel blending, along with awareness campaigns highlighting the benefits of biofuels. Additionally, vehicles using high biofuel blends should receive incentives similar to those of electric vehicles, such as access to preferential parking.