| 1. |
- Dixit, Rishibha, et al.
(author)
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Effect of Various Growth Medium on the Physiology and De Novo Lipogenesis of a Freshwater Microalga Scenedesmus rotundus-MG910488 under Autotrophic Condition
- 2022
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In: Clean Technologies. - : MDPI. - 2571-8797. ; 4:3, s. 733-751
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Journal article (peer-reviewed)abstract
- The microalga Scenedesmus rotundus, isolated from Jabalpur, Madhya Pradesh, India was designated as Scenedesmus rotundus-MG910488 after morphological and molecular identification. In this study, the effects of various autotrophic growth media on the physiology and lipid accumulation of this microalga were investigated. The cell density, amount of photosynthetic pigments, the productivity of biomass and lipid content and the cell morphology of the microalga were shown to be significantly affected by the variation in growth media. The highest biomass of 754.56 +/- 14.80 mg L-1 with biomass productivity of 37.73 +/- 0.74 mg L(-1)day(-1) was achieved when this microalgae was cultivated in the Zarrouk's medium, whereas the highest lipid content of 33.30 +/- 1.21% was observed in the BG-11 medium. The results confirm that the BG-11 is a cost-effective and efficient growth medium for this microalga. It also shows that the ingredients of the growth medium and its concentration influence the growth and synthesis of biomolecules produced by microalga. The biodiesel produced from obtained lipids was qualitatively estimated by Gas Chromatography-Mass Spectroscopy (GC-MS), Nuclear Magnetic Resonance (H-1, C-13 NMR) and Fourier Transform-Infrared Spectroscopy (FT-IR), which indicate the presence of oleic acid methyl ester, linoleic acid methyl ester and palmitic acid methyl ester as the leading fatty acid methyl esters (FAME) in the samples, which make this strain an ideal feedstock for biodiesel production.
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| 2. |
- Havilah, Pulla Rose, et al.
(author)
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Biomass Gasification in Downdraft Gasifiers: A Technical Review on Production, Up-Gradation and Application of Synthesis Gas
- 2022
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In: Energies. - : MDPI. - 1996-1073. ; 15:11
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Research review (peer-reviewed)abstract
- Rapid climate change and forecasted damage from fossil fuel combustion, forced researchers to investigate renewable and clean energy sources for the sustainable development of societies throughout the world. Biomass-based energy is one of the most important renewable energy sources for meeting daily energy needs, which are gaining in popularity daily. Gasification-based bioenergy production is an effective way to replace fossil fuels and reduce CO2 emissions. Even though biomass gasification has been studied extensively, there is still much opportunity for improvement in terms of high-quality syngas generation (high H2/CO ratio) and reduced tar formation. Furthermore, the presence of tar has a considerable impact on syngas quality. Downdraft gasifiers have recently shown a significant potential for producing high-quality syngas with lower tar concentrations. This article presents a comprehensive review on the advancement in biomass downdraft gasification technologies for high-quality synthesis gas. In addition, factors affecting syngas production and composition e.g., equivalency ratio, temperature, particle size, and gasification medium on synthesis gas generation are also comprehensively studied. The up-gradation and various applications of synthesis gas are also discussed in brief in this review article.
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| 3. |
- Karageorgou, Dimitra, et al.
(author)
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Heterotrophic Cultivation of the Cyanobacterium Pseudanabaena sp. on Forest Biomass Hydrolysates toward Sustainable Biodiesel Production
- 2022
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In: Microorganisms. - : MDPI. - 2076-2607. ; 10:9
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Journal article (peer-reviewed)abstract
- Environmental pollution, greenhouse gas emissions, depletion of fossil fuels, and a growing population have sparked a search for new and renewable energy sources such as biodiesel. The use of waste or residues as substrates for microbial growth can favor the implementation of a biorefinery concept with reduced environmental footprint. Cyanobacteria constitute microorganisms with enhanced ability to use industrial effluents, wastewaters, forest residues for growth, and concomitant production of added-value compounds. In this study, a recently isolated cyanobacterium strain of Pseudanabaena sp. was cultivated on hydrolysates from pretreated forest biomass (silver birch and Norway spruce), and the production of biodiesel-grade lipids was assessed. Optimizing carbon source concentration and the (C/N) carbon-to-nitrogen ratio resulted in 66.45% w/w lipid content when microalgae were grown on glucose, compared to 62.95% and 63.79% w/w when grown on spruce and birch hydrolysate, respectively. Importantly, the lipid profile was suitable for the production of high-quality biodiesel. The present study demonstrates how this new cyanobacterial strain could be used as a biofactory, converting residual resources into green biofuel.
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| 4. |
- Krikigianni, Eleni, et al.
(author)
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Investigating the Bioconversion Potential of Volatile Fatty Acids: Use of Oleaginous Yeasts Rhodosporidium toruloides and Cryptococcus curvatus towards the Sustainable Production of Biodiesel and Odd-Chain Fatty Acids
- 2022
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In: Applied Sciences. - : MDPI. - 2076-3417. ; 12:13
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Journal article (peer-reviewed)abstract
- Oleaginous yeasts have attracted increasing scientific interest as single cell oil (SCO) producers. SCO can be used as a fossil-free fuel substitute, but also as a source of rarely found odd-chain fatty acids (OCFAs), such as C15, C17, and C25 fatty acids which have a wide range of nutritional and biological applications. Volatile fatty acids (VFAs) have gained interest as sustainable carbon source for yeasts. This study aims to improve current knowledge on yeast species that yield high amounts of SCO using VFAs as a carbon source. Specifically, the growth of the promising yeasts Cryptococcus curvatus and Rhodotorula toruloides was evaluated on individual VFAs, such as acetic, propionic, and butyric acid. C. curvatus proved to be more tolerant in higher concentrations of VFAs (up to 60 g/L), while butyric acid favored biomass and lipid conversion (0.65 and 0.23 g/gsubstrate, respectively). For R. toruloides, butyric acid favored biomass conversion (0.48 g/gsubstrate), but lipid conversion was favored using acetic acid, instead (0.14 g/gsubstrate). Propionic acid induced the formation of OCFAs, which yielded higher amounts for C. curvatus (up to 2.17 g/L). VFAs derived from the anaerobic digestion of brewer’s spent grain were tested as a cost-competitive carbon source and illustrated the significance of the combination of different VFAs in the quality of the produced SCO, by improving the biodiesel properties and OCFAs production.
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| 5. |
- Mehariya, Sanjeet, et al.
(author)
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Improving the content of high value compounds in Nordic Desmodesmus microalgal strains
- 2022
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In: Bioresource Technology. - : Elsevier. - 0960-8524 .- 1873-2976. ; 359
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Journal article (peer-reviewed)abstract
- Nordic Desmodesmus microalgal strains (2-6) and (RUC-2) were exposed to abiotic stress (light and salt) to enhance lipids and carotenoids. The biomass output of both strains increased by more than 50% during light stress of 800 μmol m-2 s-1 compared to control light. The biomass of Desmodesmus sp. (2-6) contained most lipids (15% of dry weight) and total carotenoids (16.6 mg g-1) when grown at moderate light stress (400 μmol m-2 s-1), which further could be enhanced up to 2.5-fold by salinity stress. Desmodesmus sp. (RUC-2) exhibited maximal lipid (26.5%) and carotenoid (43.8 mg L-1) content at light intensities of 400 and 100 μmol m-2 s-1, respectively. Salinity stress stimulated lipid accumulation by 39%. Nordic Desmodesmus strains therefore are not only able to tolerate stress conditions, but their biomass considerably improves under stress. These strains have high potential to be used in algal bio-factories on low-cost medium like Baltic seawater.
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| 6. |
- Pal, Shashank, et al.
(author)
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Recent Advances in Catalytic Pyrolysis of Municipal Plastic Waste for the Production of Hydrocarbon Fuels
- 2022
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In: Processes. - : MDPI. - 2227-9717. ; 10:8
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Journal article (peer-reviewed)abstract
- Currently, the resources of fossil fuels, such as crude oil, natural gas, and coal, are depleting day by day due to increasing energy demands. Nowadays, plastic items have witnessed a substantial surge in manufacturing due to their wide range of applications and low cost. Therefore, the amount of plastic waste is increasing rapidly. Hence, the proper management of plastic wastes for sustainable technologies is the need of the hour. Chemical recycling technologies based on pyrolysis are emerging as the best waste management approaches due to their robustness and better economics. However, research on converting plastic waste into fuels and other value-added goods has yet to be undertaken, and more R&D is required to make waste-plastic-based fuels economically viable. In this review article, the current status of the plastic waste pyrolysis process is discussed in detail. Processcontrolling parameters such as temperature, pressure, residence time, reactor type, and catalyst dose are also investigated in this review paper. In addition, the application of reaction products is also described in brief. For example, plasto-oil obtained by catalytic pyrolysis may be utilized in various sectors, e.g., transportation, industrial boilers, and power generation. On the other hand, byproducts, such as solid residue (plasto-char), could be used as a road construction material or to make activated carbon or graphenes, while the non-condensable gases have a good potential to be utilized as heating/energy source.
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| 7. |
- Patel, Alok, Dr. 1989-, et al.
(author)
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A novel bioprocess engineering approach to recycle hydrophilic and hydrophobic waste under high salinity conditions for the production of nutraceutical compounds
- 2022
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In: Chemical Engineering Journal. - : Elsevier. - 1385-8947 .- 1873-3212. ; 431:Part 1
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Journal article (peer-reviewed)abstract
- The recovery of hydrophobic substrates generated by industrial oily effluents and oil spills represents a growing issue. Here, we describe a low-cost, bio-based, and environmentally friendly method for the mitigation of oil-induced water pollution. We demonstrate that a marine thraustochytrid strain could survive and utilise a record 120 g/L waste cooking oil (WCO) under highly saline conditions. Moreover, the thraustochytrid strain could convert this low-quality oil into high-quality microbial lipids rich in docosahexaenoic acid (DHA) and squalene. DHA and squalene levels were further improved via the co-utilisation of hydrophilic and hydrophobic substrates via de novo and ex novo fermentation. Hydrophobic substrate such as WCO, and volatile fatty acids (VFAs) as hydrophilic substrates generated via acidogenic fermentation increased the DHA content to 40% of total lipids and squalene to 40.47 mg/L. These values are much higher than the 23.96% and 30.21 mg/L obtained with simultaneous de novo and ex novo fermentation using glucose and WCO. The presently described method for producing nutraceutical compounds has two important benefits: (i) it enables the bioremediation of hydrophobic waste from marine environments, and (ii) it offers a sustainable and economical alternative to the use of fish oils and liver from deep-sea sharks as sources of DHA and squalene.
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| 8. |
- Patel, Alok, Dr. 1989-, et al.
(author)
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Bioprocessing of volatile fatty acids by oleaginous freshwater microalgae and their potential for biofuel and protein production
- 2022
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In: Chemical Engineering Journal. - : Elsevier. - 1385-8947 .- 1873-3212. ; 438
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Journal article (peer-reviewed)abstract
- To address the issue of high organic carbon costs in heterotrophic cultivation of microalgae, we evaluated the hypotheses by employing microalgae as a biorefinery for proteins and advanced biofuels after cultivation on volatile fatty acids (VFAs) instead of pure glucose. To prevent the inhibitory effect of VFAs on lipid synthesis, strains capable of tolerating high levels of VFAs were selected. Growth and lipid synthesis by two freshwater microalgae, Auxenochlorella protothecoides and Chlorella sorokiniana, was optimized at different VFA concentrations. Maximum biomass and lipid content in A. protothecoides (10.66 g/L, 33.93%) and C. sorokiniana (7.98 g/L, 39.80%) were obtained by replacing glucose with 30 g/L acetate at C/N 60. The generated lipids were compliant with existing standards for biodiesel. Moreover, when grown on acetate, both microalgae contained the complete range of essential and non-essential amino acids. Finally, single-source commercial VFAs were replaced with VFAs mixture after acidogenic fermentation of waste lignocellulosic biomass from brewers’ spent grain. The mixture allowed successful mixotrophic and heterotrophic cultivation of both microalgae, demonstrating feasibility of this low-cost carbon source in fuel-grade biodiesel production.
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| 9. |
- Patel, Alok, Dr. 1989-, et al.
(author)
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From Yeast to Biotechnology
- 2022
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In: Bioengineering. - : Mdpi. - 2306-5354. ; 9:12
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Journal article (other academic/artistic)abstract
- Yeasts are widely used in various sectors of biotechnology, from white (industrial) to red (medical) [...]
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| 10. |
- Patel, Alok, Dr. 1989-, et al.
(author)
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Futuristic food fortification with a balanced ratio of dietary ω-3/ω‰-6 omega fatty acids for the prevention of lifestyle diseases
- 2022
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In: Trends in Food Science & Technology. - : Elsevier. - 0924-2244 .- 1879-3053. ; 120, s. 140-153
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Journal article (peer-reviewed)abstract
- BackgroundOver the last three decades, consumption of total and saturated fat has steadily declined in Western diets as a proportion of calories intake. At the same time, omega (ω)-6 fatty acid intake has risen at the expense of ω-3 fatty acids, resulting in an ω-6/ω-3 ratio of 20:1 or higher.Scope and approachThe observed changes in fatty acids ratio coincide with a significantly increased prevalence of coronary heart disease, hypertension, cancer, diabetes, obesity, rheumatoid arthritis, and autoimmune or neurodegenerative disorders. The low intake of ω-3 fatty acids may be attributed to their absence from the diet or lack of awareness about suitable dietary sources.Key findings and conclusionsA sustainable and cost-effective way of reaching a large population with essential ω-3 fatty acids is fortification of staple foods. A variety of food items enriched with ω-3 have entered the market in recent years, including beef, fish, dairy products, cereals, cereal bars, and infant formula. The present review discusses the role of ω-3 and ω-6 fatty acids, as well as their ratio, on human health. Additionally, it focuses on the latest developments regarding dietary sources, innovative technologies, and challenges of food fortification with ω-3 fatty acids.
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