Bioproduction of yeast single cell oil with acute oral toxicity study intended for edible oil application.

Human nutrition and health rely on edible oils. Global demand for edible oils is expanding, necessitating the discovery of new natural oil sources subjected to adequate quality and safety evaluation. However, in contrast to other agricultural products, India's edible oil supply is surprisingly dependent on imports. The microbial oil is generated by fermentation of oleaginous yeast Rhodotorula mucilaginosa IIPL32 MTCC 25056 using biodiesel plant byproduct crude glycerol as a fermentable carbon source. Enriched with monounsaturated fatty acid, nutritional indices mapping based on the fatty acid composition of the yeast SCO, suggested its plausible use as an edible oil blend. In the present study, acute toxicity evaluation of the yeast SCO in C57BL/6 mice has been performed by randomly dividing the animals into 5 groups with 50, 300, 2000, and 5000 mg/Kg yeast SCO dosage, respectively, and predicted the median lethal dose (LD50). Detailed blood biochemistry and kidney and liver histopathology analyses were also reported. The functions of the liver enzymes were also evaluated to check and confirm the anticipated toxicity. To determine cell viability and in vitro biocompatibility, the 3T3-L1 cell line and haemolysis tests were performed. The results suggested the plausible use of yeast SCO as an edible oil blend due to its non-toxic nature in mice models.

Selective production of phenolic monomer via catalytic depolymerization of lignin over cobalt-nickel-zirconium dioxide catalyst.

The utilization of lignin, an abundant and renewable bio-aromatic source, is of significant importance. In this study, lignin oxidation was examined at different temperatures with zirconium oxide (ZrO2)-supported nickel (Ni), cobalt (Co) and bimetallic Ni-Co metal catalysts under different solvents and oxygen pressure. Non-catalytic oxidation reaction produced maximum bio-oil (35.3 wt%), while catalytic oxidation significantly increased the bio-oil yield. The bimetallic catalyst Ni-Co/ZrO2 produced the highest bio-oil yield (67.4 wt%) compared to the monometallic catalyst Ni/ZrO2 (59.3 wt%) and Co/ZrO2 (54.0 wt%). The selectively higher percentage of vanillin, 2-methoxy phenol, acetovanillone, acetosyringone and vanillic acid compounds are found in the catalytic bio-oil. Moreover, it has been observed that the bimetallic Co-Ni/ZrO2 produced a higher amount of vanillin (43.7% and 13.30 wt%) compound. These results demonstrate that the bimetallic Ni-Co/ZrO2 catalyst promotes the selective cleavage of the ether ß-O-4 bond in lignin, leading to a higher yield of phenolic monomer compounds.

Trigeneration based on the pyrolysis of rural waste in India: Environmental impact, economic feasibility and business model innovation.

Pyrolysis-based waste-to-bioenergy development has the potential to resolve some of the major challenges facing rural communities in India such as poor electrification, household air pollution, and farmland degradation and contamination. Existing understanding and analysis of the economic feasibility and environmental impact of bioenergy deployment in rural areas is limited by parameter uncertainties, and relevant business model innovation following economic evaluation is even scarcer. This paper uses findings from a new field survey of 1200 rural households to estimate the economic feasibility and environmental impact of a pyrolysis-based bioenergy trigeneration development that was designed to tackle these challenges. Based on the survey results, probability distributions were constructed and used to supply input parameters for cost-benefit analysis and life cycle assessment. Monte Carlo simulation was applied to characterise the uncertainties of economic feasibility and environmental impact accounting. It was shown that the global warming potential of the development was 350 kg of CO2-eq per capita per annum. Also, the survey identified a significant mismatch between feedstock prices considered in the literature and prices asked for by the surveyed villagers. The results of the cost-benefit analysis and life cycle assessment were then applied to propose two novel business models inspired by the Business Model Canvas, which had the potential to achieve up to 90 % economic profitability and result in a benefit-cost ratio of 1.35-1.75. This is the first study achieving combined environmental and economic analysis and business model innovation for rural bioenergy production in developing countries.

Enhanced remediation of polyaromatic hydrocarbon using agro-industrial waste for biofuel production and environmental pollution mitigation.

In the present study, attention has been paid to the development of economically feasible strategies for enhanced remediation of anthracene and its conversion into biofuels. The strategies developed (B1, B2, B3, and B4) include bagasse and lipid-producing strain Rhodotorula mucilagenosa IIPL32 synthesizing surface active metabolites. The results indicate the highest production of surface-active metabolites in strategies B2, B3, and B4 along with a maximum biodegradation rate. GC-MS analysis affirmed the conversion of anthracene into phthalic acid in all the strategies. Biofuel quality of the lipid produced by the strain showed higher cetane number and improved cold flow property indicating the efficiency of the developed strategies for the production of commercial grade biodiesel. Furthermore, the phytotoxicity study of the spent wash revealed that 50% and 75% diluted spent wash were non-toxic and can be employed for ferti-irrigation. Thus, the study signifies the development of an economically feasible process that can be commercially employed in biofuel industries.

Time-resolved transcriptomic profile of oleaginous yeast Rhodotorula mucilaginosa during lipid and carotenoids accumulation on glycerol.

The study reports the exploration of the transcriptome landscape of the red oleaginous yeast Rhodotorula mucilaginosa IIPL32 coinciding with the fermentation kinetics of the yeast cultivated in a two-stage fermentation process to exploit the time-series approach to get the complete transcripts picture and reveal the persuasive genes for fatty acid and terpenoid synthesis. The finding displayed the molecular drivers with more than 2-fold upregulation in the nitrogen-limited stage than in the nitrogen-excess stage. The rate-limiting diphosphomevalonate decarboxylase, acetylCoA-citrate lyase, and acetyl-CoA C-acetyltransferase were significant in controlling the metabolic flux in the synthesis of reduced compounds, and acetoacetyl-CoA synthase, 3-ketoacyl-acyl carrier-protein reductase, and ß-subunit enoyl reductase catalyze the key starting steps of lipids or terpenoid synthesis. The last two catalyze essential reduction steps in fatty acid synthesis. These enzymes would be the prime targets for the metabolic engineering of the oleaginous yeast for enhanced fatty acids and terpenoid production.

Effective utilization of discarded reverse osmosis post-carbon for adsorption of dyes from wastewater.

In this study, the deployment of post Reverse Osmosis (RO)-carbon as a adsorbent for dye removal from water has been investigated. The post RO-carbon was thermally activated (RO900), and the material thus obtained exhibited high surface area viz. 753 m2/g. In the batch system, the efficient Methylene Blue (MB) and Methyl Orange (MO) removal was obtained by using 0.08 g and 0.13 g/50 mL adsorbent dosage respectively. Moreover, 420 min was the optimized equilibration time for both the dyes. The maximum adsorption capacities of RO900 for MB and MO dyes were 223.29 and 158.14 mg/g, respectively. The comparatively higher MB adsorption was attributed to the electrostatic attraction between adsorbent and MB. The thermodynamic findings revealed the process as spontaneous, endothermic, and accompanied by entropy increment. Additionally, simulated effluent was treated, and >99% dye removal efficiency was achieved. To mimic an industrial perspective, MB adsorption onto RO900 was also carried out in continuous mode. The initial dye concentration and effluent flow rate were among the process parameters that were optimized using the continuous mode of operation. Further, the experimental data of continuous mode was fitted with Clark, Yan, and Yoon-Nelson models. Py-GC/MS investigation revealed that dye-loaded adsorbents could be pyrolyzed to produce valuable chemicals. The cost and low toxicity associated benefits of discarded RO-carbon over other adsorbents reveal the significance of the present study.

Recent advances in the role of biocatalyst in biofuel cells and its application: An overview.

Biofuel cells have recently gained popularity as a green and renewable energy source. Biofuel cells are unique devices of energy and are capable of converting the stored chemical energy from waste materials such as pollutants, organics and wastewater into reliable, renewable, pollution-free energy sources through the action of biocatalysts such as various microorganisms and enzymes. It is a promising technological device to treat waste to compensate for global warming and the energy crisis through the green energy production process. Due to their unique properties, various potential biocatalysts are attracting researchers to apply them to various microbial biofuel cells for improving electricity and power. Recent research in biofuel cells is focusing on the exploitation of different biocatalysts and how they are enhancing power generation for various applications in the field of environmental technology, and biomedical fields such as implantable devices, testing kits, and biosensors. This review focusing the importance of microbial fuel cells (MFCs) and enzymatic fuel cells (ECFs) and role of different types of biocatalysts and their mechanisms for improving biofuel cell efficiency gathered from recent reports. Finally, its multifaceted applications with special emphasis on environmental technology and biomedical field will be described, along with future perspectives.

An insight into omics analysis and metabolic pathway engineering of lignin-degrading enzymes for enhanced lignin valorization.

Lignin, a highly heterogeneous polymer of lignocellulosic biomass, is intricately associated with cellulose and hemicellulose, responsible for its strength and rigidity. Lignin decomposition is carried out through certain enzymes derived from microorganisms to promote the hydrolysis of lignin. Analyzing multi-omics data helps to emphasize the probable value of fungal-produced enzymes to degrade the lignocellulosic material, which provides them an advantage in their ecological niches. This review focuses on lignin biodegrading microorganisms and associated ligninolytic enzymes, including lignin peroxidase, manganese peroxidase, versatile peroxidase, laccase, and dye-decolorizing peroxidase. Further, enzymatic catalysis, lignin biodegradation mechanisms, vital factors responsible for lignin modification and degradation, and the design and selection of practical metabolic pathways are also discussed. Highlights were made on metabolic pathway engineering, different aspects of omics analyses, and its scope and applications to ligninase enzymes. Finally, the advantages and essential steps of successfully applying metabolic engineering and its path forward have been addressed.

Characterization of slow pyrolysis products from three different cashew wastes.

A huge amount of waste is generated by the cashew processing industries. This study aims to valorise these cashew wastes generated at different levels while processing cashew nuts in factories. The feedstocks include cashew skin, cashew shell and cashew shell de-oiled cake. Slow pyrolysis of these three different cashew wastes was performed at varying temperatures (300-500℃) at a heating rate of 10℃/min in a lab scale glass-tubular reactor under inert atmosphere of nitrogen with flow rate of 50 ml/min. The total bio-oil yield for cashew skin and the de-oiled shell cake was 37.1 and 48.6 wt% at 400℃ and 450℃, respectively. However, the maximum bio-oil yield obtained for cashew shell waste was 54.9 wt% at 500℃. The bio-oil was analysed using GC-MS, FTIR, and NMR. Along with the various functionalities observed in bio-oil through GC-MS, phenolics were observed to have maximum area% for all the feedstocks at all temperatures. At all the slow pyrolysis temperatures, cashew skin led to more biochar yield (40 wt%) as compared to cashew de-oiled cake (26 wt%) and cashew shell waste (22 wt%). Biochar was characterized by various analytical tools such as XRD, FTIR, Proximate analyser, CHNS, Py-GC/MS and SEM. Characterization of biochar revealed its carbonaceous and amorphous nature along with porosity.

Water footprint and wastewater quality assessment of yeast single cell oil production: Gate to gate approach for industrial water sustainability.

Effective water resource utilization and sustainability for industrial operations is a growing concern. With increased industrial water demand, abstraction and water quality changes are rising. In India, distilleries generate more than 40.4 billion litres of effluent daily within the fermentation industry. Water, a public good with market and opportunity costs, needs effective mapping and management. Emerging distillery processes such as yeast lipid fermentation, if developed along with water sustainability, could aid in advancing water resource management. In the scope of this idea, the present study focuses on assessing the water footprint and water quality mapping for Rhodotorula mucilaginosa IIPL32 lipid production using crude glycerol, a by-product of the biodiesel industry. The assessment was based on primary data generated during the 500 L plant scale operation. The process's blue water footprint was assessed by applying a chain-summation approach, and the grey water requirement was determined by measuring water quality parameters for the effluent streams. The process's net blue and grey water footprint were estimated to be 3.87 and 23.66 m3 water/kg of lipid, respectively. Water quality index ratings were identified for all the respective water streams within the processing system, and human risk factors were estimated. The results suggested proper treatment of the spent broth, whereas the secondary effluent stream from cleaning operations could be reutilized within the system. Quality mapping also suggested that the effluent's high organic and mineral load can be processed for water and material recovery, which may significantly reduce the process's grey water and pollution load.

Bio-oil and biochar from the pyrolytic conversion of biomass: A current and future perspective on the trade-off between economic, environmental, and technical indicators.

Over the years, the transformation of biomass into a plethora of renewable value-added products has been identified as a promising strategy to fulfil high energy demands, lower greenhouse gas emissions, and exploit under-utilized resources. Techno-economic analysis (TEA) and life-cycle assessment (LCA) are essential to scale up this process while lowering the conversion cost. In this study, trade-offs are made between economic, environmental, and technical indicators produced from these methodologies to better evaluate the commercialization potential of biomass pyrolysis. This research emphasizes the necessity of combining LCA and TEA variables to assess the performance of the early-stage technology and associated constraints. The important findings based on the LCA analysis imply that most of the studies reported in literature focussed on the global warming potentials (GWP) under environmental category by considering greenhouse gases (GHGs) as evaluation parameter, neglecting many other important environmental indices. In addition, the upstream and downstream processes play an important role in understanding the life cycle impacts of a biomass based biorefinery. Under upstream conditions, the use of a specific type of feedstock may influence the LCA conclusions and technical priority. Under downstream conditions, the product utilization as fuels in different energy backgrounds is crucial to the overall impact potentials of the pyrolysis systems. In view of the TEA analysis, investigations towards maximizing the yield of valuable co-products would play an important role in the commercialization of pyrolysis process. However, comprehensive research to compare the conventional, advanced, and emerging approaches of biomass pyrolysis from the economic perspective is currently not available in the literature.

Investigations into pyrolytic behaviour of spent citronella waste: Slow and flash pyrolysis study.

Slow and flash pyrolysis of spent citronella biomass has been studied at varying temperatures. It is aimed to understand the pyrolytic behavior of spent citronella aromatic biomass with temperatures. Maximum bio-oil yield of 37.7 wt% was obtained with conversion of 71 wt% at 450 °C through slow pyrolysis. GC/MS, 1H NMR, and FTIR analysis of pyrolytic liquid (bio-oil) was done which indicated various functionalities with maximum area% for phenolics. However, flash pyrolysis at high heating rate of 20 °C/ms resulted into maximum area% for carbonyls at all temperatures. In addition, an increasing trend for phenolics with temperature was also observed. The properties of obtained biochar are analysed by CHNS, FTIR, TOC, XRD, and SEM, which confirmed the significant decomposition of biomass constituents. The characterisation results revealed the potential usage of pyrolytic liquid i.e., bio-oil and pyrolytic residue i.e., biochar for different applications.

Efficient valorization of feather waste by Bacillus cereus IIPK35 for concomitant production of antioxidant keratin hydrolysate and milk-clotting metallo-serine keratinase.

Keratinase production by Bacillus cereus IIPK35 was investigated under solid-state fermentation (SSF) and the maximum titer of 648.28 U/gds was revealed. Feather hydrolysates obtained from SSF exhibited paramount antioxidant properties in ABTS [2,2'-azinobis-(3-ethylbenzothiazoline)-6-sulfonic acid], FRAP [Ferric ion reducing antioxidant power], and DPPH [2,2,-Diphenyl-1-picrylhydrazyl] assay. The keratinase was purified up to homogeneity have a molecular weight of 42 kDa, and showed its stability between pH 6.5-10.0 and temperature 35-60 °C with optimum enzyme activity at pH 9.0 and 55 °C. The catalytic indices viz. Km of 9.8 mg/ml and Vmax of 307.7 µmol/min for keratin were determined. Besides keratin, the enzyme displayed broad and proteolytic activity towards other proteinaceous substrates such as casein, skim milk, gelatin, and bovine serum albumin. Pure keratinase activity was stimulated in presence of Ca2+ and Mg2+ ions, while it was strongly inhibited by both iodoacetamide and EDTA, indicating it to be a metallo-serine protease in nature. Circular dichroism study endorses the structural stability of the secondary structure at the said range of pH and temperature. The IIPK35 keratinase is non-cytotoxic in nature, shows remarkable storage stability and is stable in presence of Tween 80, Triton X 100, and sodium sulfite. Furthermore, it showed excellent milk clotting potential (107.6 Soxhlet Unit), suggesting its usefulness as an alternative milk clotting agent in the dairy industry. This study unlocks a new gateway for keratinase investigation in SSF using chicken feathers as substrate and biochemical and biophysical characterization of keratinase for better understanding and implication in industrial applications.

Biochar for Supercapacitor Application: A Comparative Study.

Biochar is a carbon-rich solid that can be prepared through heat treatment of biomass under an inert atmosphere. In the present work, biochar prepared from different feedstocks, namely, Litchi chinensis (Litchi) seeds, Syzygium cumini (Jamun) seeds, and pine cone, were evaluated for charge storage in the form of supercapacitors. The physicochemical and electrochemical properties of the biochar were highly dependent on the preparation temperature and the choice of feedstock. Among the three feedstocks, Litchi seed-derived biochar showed the highest specific capacitance of 190 F g-1 at 1 A g-1 in a symmetric cell configuration. N and O heteroatom functionalities in the Litchi seed-derived biochar, higher specific surface area, and pore volume for electrolyte adsorption were responsible for its superior capacitive performance as compared to Jamun seeds and pine cone biochar.

Antibiotic bioremediation by new generation biochar: Recent updates.

The evolving multidrug resistance in microbes with increasing antibiotic pollution is becoming a severe global crisis. Recent developments on antibiotic remediations by biochar are promising. Advancements in biochar engineering enhanced biochar remediation efficiency to another level through developing new interactions and bonding abilities with antibiotic pollutants. Especially chemical/metal-composite modification significantly increased catalysis of biochar. The review's main focus is to underline biochar efficiency for the abatement of emerging antibiotic pollutants. Moreover, to relate feedstock, production conditions, and engineering techniques with biochar properties. Also, modification strategies are reviewed to obtain biochar or their composites before examining improved remediation potential ranging from 20 to 552 mg g-1 for various antibiotics. Biochar offers different interactions depending on the surface functionalities e.g., π-π stacking, electrostatic, H-bonding, etc. Biochar and related composites have also been reviewed for remarkable properties e.g., photocatalysis, adsorption, and oxidation processes. Furthermore, future research directions and opportunities for biochar research are discussed.

Oxidative catalytic valorization of industrial lignin into phenolics: Effect of reaction parameters and metal oxides.

Oxidative depolymerization of an industrial lignin was performed to study the effect of various metal oxides in oxygen and air atmosphere. CeO2 exhibited excellent catalytic property, and promoted the production of bio-oil yield up to a maximum of 49 wt% in 10 bar O2, whereas 31 wt% bio-oil was noticed in atmospheric air. GC-MS analysis of bio-oil showed that high selectivity towards acetosyringone was observed in the presence of air (70.5 area%) as compared to oxygen (48.1 area%). Herein, we have also applied transitional metals (Co, Mn and Cu) doped CeO2 catalysts. Compared to Cu and Mn, Co metal showed efficient activity that promoted the breaking of labile ß-O-4 linkages via the conversion of Cα-OH in to carbonyl group in atmospheric air resulting in the formation of acetosyringone up to 78 area%. Moreover, it exhibited excellent catalytic activity up to four successive cycles. Catalyst has been characterized by XRD, BET, TEM, FT-IR and Raman spectroscopy.

Flash hydropyrolysis of cotton stalks: Role of temperature, metal loading, pressure for enhancement of aromatics.

Hydropyrolysis of underutilized cotton stalks with catalytic upgradation was examined at different temperatures (500 to 800 °C) in the presence of nickel impregnated HY-zeolite (Ni/HY) catalysts using pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS). The effects of different metal loading (10, 15, 20 and 25 wt%) and its size were investigated to understand their impact on product distribution, mainly aromatic and aliphatic hydrocarbons. Aromatic hydrocarbons increased with an increase in metal content and optimum metal loading was 20 wt%. The pyrolysis temperature and hydrogen pressure had significant effect on product distribution. Aromatic hydrocarbon area% increased from 1.5% to 48% with an increase in temperature from 500 to 800 °C in non-catalytic hydropyrolysis. Aromatic hydrocarbon area% reached 75.5% with 20 wt% Ni/HY at 10 bar H2 pressure at 800 °C.