Biochemical engineering for elemental sulfur from flue gases through multi-enzymatic based approaches - A review.

Flue gases are the gases which are produced from industries related to chemical manufacturing, petrol refineries, power plants and ore processing plants. Along with other pollutants, sulfur present in the flue gas is detrimental to the environment. Therefore, environmentalists are concerned about its removal and recovery of resources from flue gases due to its activation ability in the atmosphere to transform into toxic substances. This review is aimed at a critical assessment of the techniques developed for resource recovery from flue gases. The manuscript discusses various bioreactors used in resource recovery such as hollow fibre membrane reactor, rotating biological contractor, sequential batch reactor, fluidized bed reactor, entrapped cell bioreactor and hybrid reactors. In conclusion, this manuscript provides a comprehensive analysis of the potential of thermotolerant and thermophilic microbes in sulfur removal. Additionally, it evaluates the efficacy of a multi-enzyme engineered bioreactor in this process. Furthermore, the study introduces a groundbreaking sustainable model for elemental sulfur recovery, offering promising prospects for environmentally-friendly and economically viable sulfur removal techniques in various industrial applications.

Evaluation of the anti-inflammatory and antioxidant properties and isolation and characterization of a new bioactive compound, 3,4,9-trimethyl-7-propyldecanoic acid from Vitex negundo.

ETHNOPHARMACOLOGICAL RELEVANCE: Herbal medicines derived from plant extraction are affordable, more therapeutically effective, and have fewer side effects than contemporary medications. Vitex negundo L. (V. negundo). is a medicinal shrub, which contains numerous phytoconstituents. In ancient medicinal practices, V. negundo was primarily prescribed as an analgesic and anti-inflammatory drug. AIM OF THE STUDY: This study aims to evaluate the anti-inflammatory and antioxidant characteristics of crude extracts from V. negundo leaves, including those derived from petroleum ether (P), methanol (M), and aqueous (A) solvents. Additionally, the research seeks to identify the specific bioactive compounds responsible for these observed properties. MATERIALS AND METHODS: The nitric oxide scavenging study was performed to evaluate the V. negundo crude extract's ability to function as a nitric oxide scavenger. Protein denaturation and proteinase inhibition experiments were employed to study the ability of extracts to suppress proteolysis and inhibit the enzymes that cause tissue injury. The membrane-stabilizing potency of plant extracts were examined through the process of heat-induced hemolysis. The ability of the extracts to neutralize free radicals showed a dose-dependent response, and the aqueous extract exhibited substantially higher activity in both FRAP and DPPH. The GC-MS analysis of V. negundo extracts revealed a vast array of pharmacologically active metabolites. Based on this Bioassay-guided fractionation approach, the optimal extract was selected for the potent molecule isolation and characterization. RESULTS: The findings demonstrated that the aqueous extract of V. negundo exhibited markedly superior radical scavenging and anti-inflammatory capabilities compared to the other two extracts. Furthermore, a new molecule, 3,4,9-trimethyl-7-propyldecanoic acid was isolated from this extract, and its chemical structure was successfully determined. CONCLUSION: This study revealed that the aqueous extract of V. negundo demonstrated notably stronger in vitro anti-inflammatory and antioxidant properties in comparison to the methanol and petroleum ether extracts. The identified active compound, 3,4,9-trimethyl-7-propyldecanoic acid is likely responsible for the extract's free radical scavenging and anti-inflammatory effects. Furthermore, conducting both in vitro and in vivo studies is crucial to substantiate the potential of this active constituent for the development of an anti-inflammatory drug derived from V. negundo.

A review of biowaste remediation and valorization for environmental sustainability: Artificial intelligence approach.

Biowaste remediation and valorization for environmental sustainability focuses on prevention rather than cleanup of waste generation by applying the fundamental recovery concept through biowaste-to-bioenergy conversion systems - an appropriate approach in a circular bioeconomy. Biomass waste (biowaste) is discarded organic materials made of biomass (e.g., agriculture waste and algal residue). Biowaste is widely studied as one of the potential feedstocks in the biowaste valorization process due to its being abundantly available. In terms of practical implementations, feedstock variability from biowaste, conversion costs and supply chain stability prevent the widespread usage of bioenergy products. Biowaste remediation and valorization have used artificial intelligence (AI), a newly developed idea, to overcome these difficulties. This report analyzed 118 works that applied various AI algorithms to biowaste remediation and valorization-related research published between 2007 and 2022. Four common AI types are utilized in biowaste remediation and valorization: neural networks, Bayesian networks, decision tree, and multivariate regression. The neural network is the most frequent AI for prediction models, the Bayesian network is utilized for probabilistic graphical models, and the decision tree is trusted for providing tools to assist decision-making. Meanwhile, multivariate regression is employed to identify the relationship between experimental variables. AI is a remarkably effective tool in predicting data, which is reportedly better than the conventional approach owing to its characteristics of time-saving and high accuracy. The challenge and future work in biowaste remediation and valorization are briefly discussed to maximize the model's performance.

Current research trends on cosmetic microplastic pollution and its impacts on the ecosystem: A review.

Since the advent of microplastics, it has become a vital component, directly or indirectly, in our daily lives. With advancements in their use, microplastics have become an integral part of personal care, cosmetics, and cleaning products (PCCPs) and emerged as a domestic source of environmental pollution. Over the years, researchers have ascertained the harmful effects of microplastics on the environment. In this context, the assessment and monitoring of microplastics in PCCPs require considerable attention. In addition, it raises concern regarding the need to develop innovative, sustainable, and environmentally safe technologies to combat microplastic pollution. Therefore, this review is an endeavor to uncover the fate, route and degradation mechanism of cosmetic microplastics. In addition, the major technological advancement in cosmetic microplastic removal and the steps directed toward mitigating cosmetic microplastic pollution are also discussed.

Multi-objective operation optimization of spent coffee ground torrefaction for carbon-neutral biochar production.

Many energy-intensive processes are employed to enhance biomass fuel properties to overcome the difficulties in utilizing biomass as fuel. Therefore, energy conservation during these processes is crucial for realizing a circular bioeconomy. This study develops a newly devised method to evaluate SCG biochars' higher heating value (HHV) and predict moisture content from power consumption. It is found that the increasing rates of HHV immediately follow decreases in power consumption, which could be used to determine the pretreatment time for energy conservation. The non-dominated sorting genetic algorithm II (NSGA-II) maximizes SCG biochar's HHV while minimizing energy consumption. The results show that producing SCG biochar with 23.98 MJ∙kg-1 HHV requires 20.042 MJ∙kg-1, using a torrefaction temperature of 244 °C and torrefaction time of 27 min and 43 sec. Every kilogram of biochar with an energy yield of 85.93 % is estimated to cost NT$ 12.21.

Lignocellulosic biomass conversion via greener pretreatment methods towards biorefinery applications.

Lignocellulose biomass during pretreatment releases various compounds, among them the most important is reducing sugars, which can be utilized for the production of biofuels and some other products. Thereby, innovative greener pretreatment techniques for lignocellulosic materials have been considered to open a new door in the aspects of digestibility of the rigid carbohydrate-lignin matrix to reduce the particle size and remove hemicellulose/lignin contents to successfully yield valid bioproducts. This article reviews about the composition of lignocelluloses and emphasizes various green pretreatments viz novel green solvent-based IL and DES steam explosion, supercritical carbon dioxide explosion (Sc-CO2) and co-solvent enhanced lignocellulosic fractionation (CELF) along with suitable mechanistic pathway of LCB pretreatment process. Finally, this article concludes that the existing pretreatments should be redesigned to conquer the demands by large scale production and suggests combined pretreatment methods to carry out various biomass pre-processing.

Phytochemical analysis, anti-inflammatory, antioxidant activity of Calotropis gigantea and its therapeutic applications.

ETHNOPHARMACOLOGICAL RELEVANCE: Herbal remedies can be used to treat a variety of chronic inflammatory illnesses, like rheumatoid arthritis and leprosy. The plant Calotropis gigantea (C. gigantea) belongs to the family Apocynaceae. To treat numerous contagious diseases, C. gigantea is utilized alone or combine with certain medicinal herbs. Traditional Asian and African practitioners employed C. gigantea to treat a variety of inflammatory conditions like boils, rheumatoid arthritis, gout, leprosy and other disorders. AIM OF THE STUDY: The goal of this study is to examine the anti-inflammatory and antioxidant activities of C. gigantea leaf extracts extracted using methanol, petroleum ether, and water. MATERIALS AND METHODS: The leaf extracts of C. gigantea were obtained using the Soxhlet extraction technique. The phytoconstituents present in all three C. gigantea leaf extracts were confirmed by qualitative analysis, and the amounts of the alkaloids, flavonoids, terpenoids and phenols found in the extracts were quantified. C. gigantea crude extracts were subjected to a nitric oxide scavenging experiment to assess their free radical scavenging activities. Protein denaturation and proteinase inhibition assays were used to investigate the effectiveness of extracts to restrict denaturation of protein and to inhibit key enzymes responsible for tissue damage. Further, the membrane stabilization efficacy of plant extracts were examined by the heat-induced hemolysis method. The DPPH and FRAP experiments were performed to determine the antioxidant effectiveness of phytoconstituents extracted using different solvents. The GC-MS study of plant C. gigantea methanolic, aqueous and petroleum ether extracts displayed a broad range of compounds that possess beneficial therapeutic effects. RESULTS: This study reveals that the methanolic extract of C. gigantea provides significantly more anti-inflammatory and antioxidant activity than other extracts. CONCLUSION: Compared to the aqueous and petroleum ether extracts, the methanolic leaf extract of C. gigantea demonstrated greater in vitro anti-inflammatory and antioxidant properties.

Technological advances in the production of carotenoids and their applications- A critical review.

Carotenoids are naturally occurring pigments that are widely distributed in algae, fungi, bacteria, and plants. Carotenoids play a significant role in the food, feed, cosmetic, nutraceutical, and pharmaceutical industries. These pigments are effectively considered as a health-promoting compounds, which are widely used in our daily diet to reduce the risk of chronic diseases such as cardiovascular diseases, cancer, acute lung injury, cataracts, neural disorders, etc. In this context, this review paper demonstrates the synthesis of carotenoids and their potential application in the food and pharmaceutical industries. However, the demand for carotenoid production is increasing overtime, and the extraction and production are expensive and technically challenging. The recent developments in carotenoid biosynthesis, and key challenges, bottlenecks, and future perspectives were also discussed to enhance the circular bioeconomy.

Emerging technologies and potential applications of algae in dentistry - A critical review.

Algae are effective predecessors of nutrient foods and preventive drugs, gaining global attraction in recent years. It exhibits potent antiviral, antibacterial, antifungal, anti-inflammatory, antioxidant, anti-glycemic, and cholesterol-lowering properties due to their richness in highly valuable secondary metabolites. Nevertheless, algae produce valuable bioproducts, its application in dentistry is in its primitive stage. This review focuses on the emergence and emerging role of micro/macroalgae as a natural source of therapeutic, preventive, and biocompatible agents in dentistry. Several studies unveiled that Cyanobacteria, Spirulina, and Chlorella species offer high oral antibacterial and antifungal properties compared to gold standard agents. The characteristic of algae to scavenge superoxide and hydroxyl free radicals, fabricate them as an anti-oxidative and anti-cancer agent. Either alone or by synergism with pinnacle therapies they are found to produce promising curative actions against periodontitis by embattling proinflammatory cytokines. Technologies extend the functions of microalgae as a detoxifying agent, potent drug delivery system, and adjunct regenerative material in chronic periodontitis. Its application as thickening, binding, anticariogenic agent in toothpaste, antibacterial agent in mouthwash, and biocompatible agent in dental impression materials remains very primitive. Low-cost and eco-friendly technologies are needed for the production of oral hygiene products using algal biomass.

Microalgae cultivation strategies using cost-effective nutrient sources: Recent updates and progress towards biofuel production.

Scientists are grabbing huge attention as well as consciousness on non-renewable energy sources for the global energy crises because of gradual increase in oil price, fast depletion or low availability of resources, and the release of more toxic-gases (CO2, SOx, NxO) during exhaustion, etc. Due to such hitches, the key need is to find alternative biofuels or feedstocks to replace fossil fuel energy demands worldwide. Currently, microalgae have become intrigued feedstock candidates (3rd generation source of biofuel) to replace nearly 50-60 % of fossil fuels due to high production of biomass and oil, mitigating CO2 and wastewater remediation. The present work demonstrated the current developments and future perspectives on large-scale algal cultivation strategies for the biorefinery economy. In addition, various advanced cultivation techniques adopted for enhanced biomass production and cost-effective methods for bioenergy production were detailly discussed.

Bioelectrochemical systems in aid of sustainable biorefineries for the production of value-added products and resource recovery from wastewater: A critical review and future perspectives.

Bioelectrochemical systems (BES) have the potential to be used in a variety of applications such as waste biorefinery, pollutants removal, CO2 capture, and the electrosynthesis of clean and renewable biofuels or byproducts, among others. In contrast, many technical challenges need to be addressed before BES can be scaled up and put into real-world applications. Utilizing BES, this review article presents a state-of-the-art overall view of crucial concepts and the most recent innovative results and achievements acquired from the BES system. Special attention is placed on a hybrid approach for product recovery and wastewater treatment. There is also a comprehensive overview of waste biorefinery designs that are included. In conclusion, the significant obstacles and technical concerns found throughout the BES studies are discussed, and suggestions and future requirements for the virtual usage of the BES concept in actual waste treatment are outlined.

SDS-Aluminum Oxide Nanofluid for Enhanced Oil Recovery: IFT, Adsorption, and Oil Displacement Efficiency.

Surfactant flooding is one of the most promising chemical enhanced oil recovery (CEOR) methods to produce residual oil in reservoirs. Recently, nanoparticles (NPs) have attracted extensive attention because of their significant characteristics and capabilities to improve oil recovery. The aim of this study is to scrutinize the synergistic effect of sodium dodecyl sulfate (SDS) as an anionic surfactant and aluminum oxide (Al2O3) on the efficiency of surfactant flooding. Extensive series of interfacial tension and surfactant adsorption measurements were conducted at different concentrations of SDS and Al2O3 NPs. Furthermore, different surfactant adsorption isotherm models were fitted to the experimental data, and constants for each model were calculated. Additionally, oil displacement tests were performed at 25 °C and atmospheric pressure to indicate the suitability of SDS-Al2O3 for CEOR. Analysis of this study shows that the interfacial tension (IFT) reduction between aqueous phase and crude oil is enhanced considerably by 76%, and the adsorption density of SDS onto sandstone rock is decreased remarkably from 1.76 to 0.49 mg/g in the presence of these NPs. Although the effectiveness of NPs gradually increases with the increase of their concentration, there is an optimal value of Al2O3 NP concentration. Moreover, oil recovery was increased from 48.96 to 64.14% by adding 0.3 wt % NPs to the surfactant solution, which demonstrates the competency of SDS-Al2O3 nanofluids for CEOR.

Marine biome-derived secondary metabolites, a class of promising antineoplastic agents: A systematic review on their classification, mechanism of action and future perspectives.

Cancer is one of the most deadly diseases on the planet. Over the past decades, numerous antineoplastic compounds have been discovered from natural resources such as medicinal plants and marine species as part of multiple drug discovery initiatives. Notably, several marine flora (e.g. Ascophyllum nodosum, Sargassum thunbergii) have been identified as a rich source for novel cytotoxic compounds of different chemical forms. Despite the availability of enormous chemically enhanced new resources, the anticancer potential of marine flora and fauna has received little attention. Interestingly, numerous marine-derived secondary metabolites (e.g., Cytarabine, Trabectedin) have exhibited anticancer effects in preclinical cancer models. Most of the anticancer drugs obtained from marine sources stimulated apoptotic signal transduction pathways in cancer cells, such as the intrinsic and extrinsic pathways. This review highlights the sources of different cytotoxic secondary metabolites obtained from marine bacteria, algae, fungi, invertebrates, and vertebrates. Furthermore, this review provides a comprehensive overview of the utilisation of numerous marine-derived cytotoxic compounds as anticancer drugs, as well as their modes of action (e.g., molecular target). Finally, it also discusses the future prospects of marine-derived drug developments and their constraints.

Recent developments in biorefining of macroalgae metabolites and their industrial applications - A circular economy approach.

The macroalgal industry is expanding, and the quest for novel ingredients to improve and develop innovative products is crucial. Consumers are increasingly looking for natural-derived ingredients in cosmetic products that have been proven to be effective and safe. Macroalgae-derived compounds have growing popularity in skincare products as they are natural, abundant, biocompatible, and renewable. Due to their high biomass yields, rapid growth rates, and cultivation process, they are gaining widespread recognition as potentially sustainable resources better suited for biorefinery processes. This review demonstrates macroalgae metabolites and their industrial applications in moisturizers, anti-aging, skin whitening, hair, and oral care products. These chemicals can be obtained in combination with energy products to increase the value of macroalgae from an industrial perspective with a zero-waste approach by linking multiple refineries. The key challenges, bottlenecks, and future perspectives in the operation and outlook of macroalgal biorefineries were also discussed.

Recent advances in lignocellulosic biomass for biofuels and value-added bioproducts - A critical review.

Lignocellulosic biomass is a highly renewable, economical, and carbon-neutral feedstock containing sugar-rich moieties that can be processed to produce second-generation biofuels and bio-sourced compounds. However, due to their heterogeneous multi-scale structure, the lignocellulosic materials have major limitations to valorization and exhibit recalcitrance to saccharification or hydrolysis by enzymes. In this context, this review focuses on the latest methods available and state-of-the-art technologies in the pretreatment of lignocellulosic biomass, which aids the disintegration of the complex materials into monomeric units. In addition, this review deals with the genetic engineering techniques to develop advanced strategies for fermentation processes or microbial cell factories to generate desired products in native or modified hosts. Further, it also intends to bridge the gap in developing various economically feasible lignocellulosic products and chemicals using biorefining technologies.

Biofilm mediated decolorization and degradation of reactive red 170 dye by the bacterial consortium isolated from the dyeing industry wastewater sediments.

Reactive dyes are extensively used in a plethora of industries, which in turn release toxic wastes into the environment. The textile dye waste remediation is crucial as it may contain several toxic elements. The utilization of bacterial consortium for bioremediation has acquired consideration, over the utilization of single strains. In this study, a microbial consortium containing three bacterial sp. (Bacillus subtilis, Brevibacillus borstelensis and Bacillus firmus) was tested for its degrading ability of the textile RR 170 dye. The bacterial consortium degraded the dye effectively at lower concentrations and the efficiency decreased as the dye concentration increased. SEM analysis revealed that, with dye treatment, the consortium appeared as tightly packed clumps with rough cell surface and were able to produce EPS and biofilms. EPS production was higher at 40 mg/l, 100 mg/l and 200 mg/l of the dye treatment conditions. Interestingly, the maximum biofilm formation was observed only at 40 µg/ml of the dye treatment, which indicates that RR 170 dye concentration affects the biofilm formation independent of EPS levels. The UV-vis spectroscopy, HPLC, FTIR and 2D-FTIR analyses confirmed the decolorization and biodegradation of RR 170 dye by the bacterial consortium. Toxicological studies performed with the dye and their degraded products in Allium cepa root cells revealed that, whereas the RR 170 dye induced genotoxic stress, the degraded dye products showed no significant genotoxic effects in root cells. Together, the investigated bacterial consortium decolorized and degraded the RR 170 dye resulting in metabolites that are non-toxic to the living cells.

Ameliorative photocatalytic dye degradation of hydrothermally synthesized bimetallic Ag-Sn hybrid nanocomposite treated upon domestic wastewater under visible light irradiation.

Industrial and textile dyes are the major source of water pollutants in the Coimbatore Districts of Tamil Nadu, India. The highly stable organic dyes from these industries are being discharged untreated into neighboring rivers, lakes, and ponds. Thus, the present study mainly focused on the preparation of bimetallic nanocomposite (Ag-Sn) through Free-facile Teflon autoclave methodology and their subsequent stimulation has given to the photocatalyst by visible light irradiation. This visible light stimulates and irradiates the photocatalysts from steady state to the excited state and might help in absorption of the nanosized dye materials and organic matter. The nanocomposite was characterized using UV, FTIR, Zeta-sizer, XRD and FE-SEM. These parameters exhibited significant lattice structures with an average size of 127.6 nm. Further the nanocomposite treated samples were tested for water quality parameters like TDS, BOD, COD, heavy metals, sedimentation rate and bacterial population. Likewise, the samples irradiated with visible light for photocatalytic activity exhibited a significant intensity of C/C0 at 0.42 and 0.28. The treated water used for green gram seedling assay exhibited significant growth. Scavengers from Ag-Sn bimetallic nanocomposite plays the major role in dye degradation. The results clearly suggest that Ag-Sn bimetallic nanocomposite can be used for wastewater treatment and the subsequent treated water can be utilized for agriculture purposes.

Novel strategy in biohydrogen energy production from COVID - 19 plastic waste: A critical review.

Usage of plastics in the form of personal protective equipment, medical devices, and common packages has increased alarmingly during these pandemic times. Though they have served as an excellent protection source in minimizing the coronavirus disease (COVID-19) spreading, they have still emerged as major environmental pollutants nowadays. These non-degradable COVID-19 plastic wastes (CPW) were treated through incineration and landfilling process, which may lead to either the release of harmful gases or contaminating the surrounding environment. Further, they can cause numerous health hazards to the human and animal populations. These plastic wastes can be efficiently managed through thermochemical processes like pyrolysis or gasification, which assist in degrading the plastic waste and also effectively convert them into useful energy-yielding products. The pyrolysis process promotes the formation of liquid fuels and chemicals, whereas gasification leads to syngas and hydrogen fuel production. These energy-yielding products can help to compensate for the fossil fuels depletion in the near future. There are many insights explained in terms of the types of reactors and influential factors that can be adopted for the pyrolysis and gasification process, to produce high efficient energy products from the wastes. In addition, advanced technologies including co-gasification and two-stage gasification were also reviewed.

Sargassum myriocystum-mediated TiO2-nanoparticles and their antimicrobial, larvicidal activities and enhanced photocatalytic degradation of various dyes.

Recently, the phyco-synthesis of nanoparticles has been applied as a reliable approach to modern research field, and it has yielded a wide spectrum of diverse uses in fields such as biological science and environmental science. This study used marine natural resource seaweed Sargassum myriocystum due to their unique phytochemicals and their significant attributes in giving effective response on various biomedical applications. The response is created by their stress-tolerant environmental adaptations. This inspired us to make an attempt using the above-mentioned charactersitics. Therfore, the current study performed phycosynthesis of titanium dioxide nanoparticles (TiO2-NPs) utilising aqueous extracts of S. myriocystum. The TiO2-NPs formation was confirmed in earlier UV-visible spectroscopy analysis. The crystalline structure, functional groups (phycomolecules), particle morphology (cubic, square, and spherical), size (∼50-90 nm), and surface charge (negative) of the TiO2-NPs were analysed and confirmed by various characterisation analyses. In addition, the seaweed-mediated TiO2-NPs was investigated, which showed potential impacts on antibacterial activity and anti-biofilm actions against pathogens (Staphylococcus aureus, S. epidermidis, Escherichia coli, Proteus vulgaris, Pseudomonas aeruginosa, and Klebsiella pneumoniae). Additionally, some evaluations were performed on larvicidal activities of TiO2-NPs in oppose to Aedes aegypti and Culex quinquefasciatus mosquitos and the environmental effects of photocatalytic activities against methylene blue and crystal violet under sunlight irradiation. The highest percent of methylene blue degradation was observed at 92.92% within 45 min. Overall, our findings suggested that S. myriocystum mediates TiO2-NPs to be a potent disruptive material for bacterial pathogens and mosquito larvae and also to enhance the photocatalytic dye degradation.