Lignocellulosic bioethanol is a promising renewable energy source that can reduce greenhouse gas emissions and improve energy security. However, its commercialization faces significant economic and environmental challenges, including high feedstock costs, complex pretreatment processes, expensive enzyme formulations, and substantial energy and water requirements. This review examines the key factors affecting its viability, including feedstock costs, enzyme efficiency, co-product generation, greenhouse gas emissions, water use, energy efficiency, and land use impacts. Recent advancements in pretreatment technologies, enzyme recycling, genetically engineered microbial strains, and fermentation strategies are discussed for their potential to improve process efficiency and reduce production costs. This review also explores co-product valorization, including lignin and biogas utilization, which can enhance the economic sustainability of bioethanol production by generating additional revenue streams, offsetting operational costs, and improving overall process efficiency. Identifying research gaps, it highlights the need for cost-effective feedstock supply chains, advanced enzyme technologies, and optimized fermentation methods. Additionally, the role of life cycle assessments and government policies, including subsidies, is considered in shaping production costs and the environmental impact. By integrating economic and environmental perspectives, this review provides insights into advancing the sustainable production of lignocellulosic bioethanol, emphasizing the importance of continued innovation to overcome existing challenges.

Dental caries is a biofilm-mediated, sugar-driven, multifactorial, dynamic disease that results in the phasic demineralization and remineralization of dental hard tissues. Despite scientific advances in cariology, dental caries remains a severe global concern. The aim of this study was to determine the optimization of microbial and molecular techniques for the detection of cariogenic pathogens in dental caries patients, the prevalence of cariogenic bacteria on the basis of socioeconomic, climatological, and hygienic factors, and in vitro evaluation of the antimicrobial activity of selected synthetic antibiotics and herbal extracts. In this study, oral samples were collected from 900 patients for bacterial strain screening on a biochemical and molecular basis. Plant extracts, such as ginger, garlic, neem, tulsi, amla, and aloe vera, were used to check the antimicrobial activity against the isolated strains. Synthetic antimicrobial agents, such as penicillin, amoxicillin, erythromycin, clindamycin, metronidazole, doxycycline, ceftazidime, levofloxacin, and ciprofloxacin, were also used to access the antimicrobial activity. Among 900 patients, 63% were males and 37% were females, patients aged between 36 and 58 (45.7%) years were prone to disease, and the most common symptom was toothache (61%). For oral diseases, 21% used herbs, 36% used antibiotics, and 48% were self-medicated, owing to sweets consumption (60.66%) and fizzy drinks and fast food (51.56%). Staphylococcus mutans (29.11%) and Streptococcus sobrinus (28.11%) were found as the most abundant strains. Seven bacterial strains were successfully screened and predicted to be closely related to genera S. sobrinus, S. mutans, Actinomyces naeslundii, Lactobacillus acidophilus, Eubacterium nodatum, Propionibacterium acidifaciens, and Treponema Pallidum. Among plant extracts, the maximum zone of inhibition was recorded by ginger (22.36 mm) and amla (20.01 mm), while among synthetic antibiotics, ciprofloxacin and levofloxacin were most effective against all microbes. This study concluded that phyto extracts of ginger and amla were considered suitable alternatives to synthetic antibiotics to treat dental diseases.

Bioethanol manifests an extraordinary potential to overcome the severe energy crises and reliance on fossil fuels, yet it supports the sustainable and cost-effective production of fuels for automobile engines and contributes to the reduction of greenhouse gas (GHG) emissions and other global climate-related challenges. The present study examines the potential of Mixed Lignocellulosic Biomass (MLB) as a sustainable feedstock for the consistent year-round production of bioethanol. The primary MLB sources considered in this research to underscore the significance of this heterogeneous strategy include sweet sorghum bagasse (SSB), sugarcane bagasse (SCB), and date palm trunk (DPT). Each of the three feedstocks, i.e., SSB, SCB, and DPT, were individually subjected to alkaline pretreatment, a step aimed at breaking down structural barriers and facilitating greater release of fermentable sugars during fermentation. Likewise, the alkaline-pretreated biomasses were subjected to simultaneous saccharification and fermentation (SSF) for 96 h, both individually as well as in various combined proportions. Individually, pretreated sweet sorghum bagasse (SSB) fibers produced the highest ethanol concentration, of 30.79 ± 0.44 g/L; an ethanol yield of 0.40 ± 0.62 g/g; an ethanol productivity of 0.42 ± 0.87 g/L/h; and a theoretical ethanol yield of 79.81% at 72 h. In contrast, the combination of MLB (50% of pretreated SSB and 50% of DPT fibers) produced a significantly higher ethanol concentration of 31.47 ± 0.57 g/L and an ethanol productivity of 0.653 ± 0.24 g/L/h in much less time, i.e., 48 h of SSF fermentation. The empirical data confirms that MLB offers a sustainable paradigm for ethanol biosynthesis by curtailing fermentation time and optimizing economic and operational efficacy.

Oil palm frond as an abundant and inexpensive lignocellulosic waste was used to optimize alkaline pretreatment for ethanol production. The studied lignocellulosic waste is one of the largest biomasses (47%) in oil palm waste. Oil palm frond fibers were processed by steam explosion, hot water extraction, and alkaline extraction pretreatment, followed by simultaneous saccharification and fermentation (SSF), for ethanol production as an alternative energy resource. To optimize alkaline extraction for oil palm frond, a Taguchi method with a three-factor design constituted a concentration of NaOH (15%, 20%, and 25%), time (30, 60, and 90 min), and temperature (70, 80, and 90 °C). An optimum alkaline extraction condition of 15% NaOH at 90 °C for 60 min gave the highest percentage of α-cellulose (80.74%) and the lowest percentages of lignin (15.99%), ash (1.05%), and pentosan (2.09%). In addition, the optimized pretreatment condition significantly improved α-cellulose to 52.65% and removed lignin up to 51.78%. Simultaneous saccharification and fermentation (SSF) was carried out with 10% (dry weight) alkaline pretreated OPF fibers, Celluclast 1.5 L (15 FU/gram substrate), Novozyme 188 (15 IU/gram substrate), and Saccharomyces cerevisiae SC90 at 40 and 45 °C. The highest ethanol concentration, theoretical ethanol yield, and ethanol productivity observed at 40 °C were 33.15 g/L, 72.54%, and 0.55 g/L/h, respectively. The results suggest that an optimized alkaline pretreatment process using palm frond as a lignocellulosic waste is a sustainable approach to produce efficient ethanol production.