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Abstract Anaerobic digestion (AD) technology can potentially address the gap between energy demand and supply playing a crucial role in the production of sustainable energy from utilization of biogenic waste materials as feedstock. The biogas production from anaerobic digestion is primarily influenced by the chemical compositions and biodegradability of the feedstock. Organosolv-steam explosion offers a constructive approach as a promising pretreatment method for the fractionation of lignocellulosic biomasses delivering high cellulose content.This study showed how synergetic co-digestion serves to overcome the challenges of mono-digestion's low efficiency. Particularly, the study evaluated the digestibility of organosolv-steam pretreated wheat straw (WSOSOL) in mono as well as co-digesting substrate with cheese whey (CW) and brewery spent grains (BSG). The highest methane yield was attained with co-digestion of WSOSOL + CW (338 mL/gVS) representing an enhanced biogas output of 1–1.15 times greater than its mono digestion. An ammonium production was favored under co-digestion strategy accounting for 921 mg/L from WSOSOL + BSG. Metagenomic study was conducted to determine the predominant bacteria and archaea, as well as its variations in their populations and their functional contributions during the AD process. The Firmicutes have been identified as playing a significant role in the hydrolysis process and the initial stages of AD. An enrichment of the most prevalent archaea genera enriched were Methanobacterium, Methanothrix, and Methanosarsina. Reactors digesting simpler substrate CW followed the acetoclastic, while digesting more complex substrates like BSG and WSOSOL followed the hydrogenotrophic pathway for biomethane production. To regulate the process for an enhanced AD process to maximize CH4, a comprehensive understanding of microbial communities is beneficial.

Abstract Botryococcus braunii, a colonial green microalga which is well-known for its capacity to synthesize hydrocarbons, has significant promise as a long-term source of feedstock for the generation of biofuels. However, cultivating and scaling up B. braunii using conventional aqua-suspended cultivation systems remains a challenge. In this study, we optimized medium components and light intensity to enhance lipid and hydrocarbon production in a multi-cultivator airlift photobioreactor. BBM 3N medium with 200 μmol/m2/s light intensity and a 16 h light–8 h dark regimen yielded the highest biomass productivity (110.00 ± 2.88 mg/L/day), as well as the highest lipid and hydrocarbon content. Cultivation in a flat-panel bioreactor resulted in significantly higher biomass productivity (129.11 ± 2.74 mg/L/day), lipid productivity (32.21 ± 1.31 mg/L/day), and hydrocarbon productivity (28.98 ± 2.08 mg/L/day) compared to cultivation in Erlenmeyer flasks and open 20-L raceway pond. It also exhibited 20.15 ± 1.03% of protein content including elevated levels of chlorophyll a, chlorophyll b, and carotenoids. This work is noteworthy since it is the first to describe fatty acid and hydrocarbon profiles of B. braunii during cobalt treatment. The study demonstrated that high cobalt concentrations (up to 5 mg/L of cobalt nitrate) during Botryococcus culture affected hydrocarbon synthesis, resulting in high amounts of n-alkadienes and trienes as well as lipids with elevated monounsaturated fatty acids concentration. Furthermore, pyrolysis experiments on microalgal green biomass and de-oiled biomass revealed the lipid and hydrocarbon compounds generated by the thermal degradation of B. braunii that facilitate extra economical value to this system.

Abstract Background Biotransformation of waste oil into value-added nutraceuticals provides a sustainable strategy. Thraustochytrids are heterotrophic marine protists and promising producers of omega (ω) fatty acids. Although the metabolic routes for the assimilation of hydrophilic carbon substrates such as glucose are known for these microbes, the mechanisms employed for the conversion of hydrophobic substrates are not well established. Here, thraustochytrid Schizochytrium limacinum SR21 was investigated for its ability to convert oils (commercial oils with varying fatty acid composition and waste cooking oil) into ω-3 fatty acid; docosahexaenoic acid (DHA). Results Within 72 h SR21 consumed ~ 90% of the oils resulting in enhanced biomass (7.5 g L− 1) which was 2-fold higher as compared to glucose. Statistical analysis highlights C16 fatty acids as important precursors of DHA biosynthesis. Transcriptomic data indicated the upregulation of multiple lipases, predicted to possess signal peptides for secretory, membrane-anchored and cytoplasmic localization. Additionally, transcripts encoding for mitochondrial and peroxisomal β-oxidation along with acyl-carnitine transporters were abundant for oil substrates that allowed complete degradation of fatty acids to acetyl CoA. Further, low levels of oxidative biomarkers (H2O2, malondialdehyde) and antioxidants were determined for hydrophobic substrates, suggesting that SR21 efficiently mitigates the metabolic load and diverts the acetyl CoA towards energy generation and DHA accumulation. Conclusions The findings of this study contribute to uncovering the route of assimilation of oil substrates by SR21. The thraustochytrid employs an intricate crosstalk among the extracellular and intracellular molecular machinery favoring energy generation. The conversion of hydrophobic substrates to DHA can be further improved using synthetic biology tools, thereby providing a unique platform for the sustainable recycling of waste oil substrates.

Bioelectrochemical systems (BES) are emerging as potential technologies that can remediate acid mine drainage (AMD) by cathodic reduction of sulfates to metal sulfides. This study evaluated bioelectrochemical remediation of sulfate rich AMD at two applied cathode potentials; BES-1: −1.0 V and BES-2: −0.8 V. Sulfate reducing bacteria were selectively enriched to be used as biocatalyst in BES. Initially, lactate was fed as carbon source and switched to chemolithoautotrophy with only CO2-fed conditions. Both BESs were operated at 3±0.2 g/l of sulfate with synthetic AMD (SAMD) fed first, and gradually changed to 50% AMD from mining site with 50% SAMD. Sulfate reduction was relatively higher with BES-1: 82% than BES-2: 76% coupled with sulfidogenesis. Interestingly, acetogenesis (BES-1: 2.12±0.2 g/l, BES-2: 1.9±0.2 g/l) was also noticed with high reduction currents (BES-1&2: >-70 mA). Microbiome community analysis revealed the dominant presence of sulfate reducers, acetogens, syntrophic bacteria and Methanobacterium, probing microbial synergy aiding sulfate reduction. An added advantage was the iron-sulfide (FeS) particles formation on cathode, which might have contributed to increased reduction currents. This study reveals insights into microbial synergy for autotrophic sulfate reduction within mixed microbiome communities along with the impact of FeS particles as conducive facilitator for electron transfer in BES, thereby enhancing electrosynthetic acetate production.

Lignin, an abundant renewable biopolymer found in plant cell walls, is enriched in phenolic units within its complex molecular structure. Unlocking its potential as alternative feedstock in (bio)refining has posed a long-standing challenge, even though it holds immense promise for replacing fossil-derived phenolic and aromatic compounds. This study focuses on fast pyrolysis as effective thermochemical depolymerization method of lignin, coupled with the in situ catalytic upgrading aiming to produce valuable bio-oil enriched in dealkoxylated (alkyl)phenolic and aromatic compounds. Lignin was isolated via the organosolv process from beechwood sawdust (hardwood biomass). Various acidic aluminosilicate catalysts (e.g., zeolites, such as ZSM-5, Beta and USY, and amorphous silica alumina) were applied, having different Si/Al ratio, porous and acidic properties. Fast pyrolysis experiments were conducted on a fixed-bed bench-scale reactor at two distinct temperatures (500 and 600 °C), employing different contact times and lignin-to-catalyst ratios. Non-catalytic pyrolysis experiments revealed that higher temperature, significantly influences bio-oil’s composition and yield, resulting in the conversion of initially formed alkoxy-phenols to alkyl-phenolic compounds, reaching a 47% relative concentration at 600 °C, while also yielding high amount of bio-oil up to 43 wt%. Among the catalysts tested, zeolite ZSM-5 (Si/Al=40) proved to be the most efficient, shifting the chemical profile of bio-oil from phenolic to aromatic (mainly BTX) with relative concentration of 57%, owing to its unique microporous structure and acidity. Depending on the catalyst type, a balance between BTX monomer aromatics and naphthalenes was observed. Lignin, as well as the obtained products (bio-oil, non-condensable gases, char/coke-on-catalyst) were thoroughly characterized using various analytical techniques. The catalytic upgrading results were associated with the physicochemical properties of the catalysts, providing valuable insights into the underlying reaction mechanisms.

Lignocellulosic biomass represents an excellent alternative to fossil fuels in terms of both energy production and raw material usage for a plethora of daily-use products. Organosolv pretreatment is a fractionation technique able to separate lignocellulosic biomass into individual streams of cellulose, hemicellulose, and lignin under controlled conditions. Sawdust, the by-product of sawmill processing of Picea abies wood, was the subject of our investigation in this work. The aim was to evaluate the effects of different parameters of the organosolv process of spruce sawdust on the yield of components and how this affects the enzymatic saccharification of cellulose. Sixteen distinct pretreatments were performed with ethanol concentrations of 50 and 60% v/v at 180 and 200 °C for 15 and 30 min. Half of the pretreatments contained 1% sulfuric acid as a catalyst, while the other half were acid-free. Thereafter, the effects of different variables on the yield of products were assessed and compared to determine the ideal pretreatment condition. The results showed that cellulose-rich pulps, with cellulose content as high as 55% were generated from an initial mass of 37.7% spruce sawdust with the reactor operating at 180 °C for 30 min using 60% ethanol and 1% sulfuric acid. With the pretreatments performed with the catalyst at 200 °C, hemicellulose was almost entirely removed from the pulps obtained. The recovered hemicellulose fraction was composed mainly of monomers achieving up to 10 g/100 g of biomass. Delignification values of up to 65.7% were achieved with this pretreatment technique. Fractionated lignin presented low levels of sugar and ashes contamination, with values as low as 1.29% w/w. Enzymatic saccharification of the pretreated pulps yielded 78% cellulose hydrolysis, with glucose release higher than 0.54 g/g of biomass, indicating the potential of the pulps to be applied in a fermentation process.

Metal nanoparticle synthesis via environmentally friendly methods is gaining interest for their potential advantages over conventional physico-chemical approaches. Herein, we propose a robust green synthesis route for lignin-modified silver nanoparticles, utilizing the recovery of lignin as a renewable raw material and exploring its application in valuable areas. Through a systematic approach combining UV-Vis spectroscopy with AAS and DLS, we identified repeatable and scalable reaction conditions in an aqueous solution at pH 11 for homogeneous silver nanoparticles with high uniformity. The TEM median sizes ranged from 12 to 15 nm with circularity between 0.985 and 0.993. The silver nanoparticles yield exceeded 0.010 mol L−1, comparable with traditional physico-chemical methods, with a minimal loss of silver precursor ranging between 0.5 and 3.9%. Characterization by XRD and XPS revealed the presence of Ag-O bonding involving lignin functional groups on the pure face-centered cubic structure of metallic silver. Moreover, the lignin-modified silver nanoparticles generated a localized thermal effect upon near-infrared laser irradiation (808 nm), potentially allowing for targeted applications in the biomedical field. Our study showcases the potential of lignin as a renewable reducing and capping agent for silver nanoparticle synthesis, addressing some shortcomings of green synthesis approaches and contributing to the development of suitable nanomaterials.

Abstract Background Brewer's spent grain (BG), a by-product of the brewing process, is attracting increasing scientific interest as a low-cost feedstock for many biotechnological applications. BG in the present study is evaluated as a substrate for lignocellulolytic enzyme production and for the production of ethanol by the mesophilic fungus Fusarium oxysporum under submerged conditions, implementing a consolidated bioconversion process. Fermentation experiments were performed with sugar mixtures simulating the carbohydrate content of BG in order to determine the utilization pattern that could be expected during the fermentation of the cellulose and hemicellulose hydrolysate of BG. The sugar mixture fermentation study focused on the effect of the initial total sugar concentration and on the effect of the aeration rate on fermenting performance of F. oxysporum. The alkali pretreatment of BG and different aeration levels during the ethanol production stage were studied for the optimization of the ethanol production by F. oxysporum. Results Enzyme yields as high as 550, 22.5, 6.5, 3225, 0.3, 1.25 and 3 U per g of carbon source of endoglucanase, cellobiohydrolase, β-D-glucosidase, xylanase, feruloyl esterase, β-D-xylosidase and α-L-arabinofuranosidase respectively, were obtained during the growth stage under optimized submerged conditions. An ethanol yield of 109 g ethanol per kg of dry BG was obtained with alkali-pretreated BG under microaerobic conditions (0.01 vvm), corresponding to 60% of the theoretical yield based on total glucose and xylose content of BG. Conclusion The enzymatic profile of the extracellular extract from F. oxysporum submerged cultures using BG and corn cob as the carbon source was proved efficient for a successful hydrolysis of BG. The fermentation study carried out using sugar mixtures simulating BG's carbohydrates content and consecutively alkali-pretreated and untreated BG, indicates that BG hydrolysis is the bottleneck of the bioconversion process. However, a considerable bioconversion yield was achieved (60% of the theoretical) making this bioprocess worthy of further investigation for a potential commercial application.

The present research investigated the effect of organosolv pretreatment on two species of salt-tolerant Salicornia spp. biomass, Salicornia dolichostachya and Salicornia ramosissima, for increasing biomethane production through anaerobic digestion. The final biomethane yield of de-juiced green fibers of Salicornia spp. from wet fractionation increased by 23–28% after organosolv treatment. The highest methane yield of about 300 mL-CH4/gVS was found after organosolv treatment with 60% v/v ethanol solution at 200 °C for 30 min, or at 180 °C for 30 or 60 min treatment time. Furthermore, the methane production rate increased significantly, reducing the time until 95% of the final methane yield was reached from 20 days to 6–10 days for the organosolv-treated biomass. This research shows that the process of anaerobic digestion of halophyte biomass benefits from cascade processing of Salicornia fibers in a biorefinery framework by sequential wet and organosolv fractionation for full utilization of halophytic biomass.

Abstract The present study reports the mixed culture acidogenic production of biohydrogen and carboxylic acids (CA) from brewery spent grains (BSG) in the presence of high concentrations of cobalt, iron, nickel, and zinc. The metals enhanced biohydrogen output by 2.39 times along with CA biosynthesis by 1.73 times. Cobalt and iron promoted the acetate and butyrate pathways, leading to the accumulation of 5.14 gCOD/L of acetic and 11.36 gCOD/L of butyric acid. The production of solvents (ethanol + butanol) was higher with zinc (4.68 gCOD/L) and cobalt (4.45 gCOD/L). A combination of all four metals further enhanced CA accumulation to 42.98 gCOD/L, thus surpassing the benefits accrued from supplementation with individual metals. Additionally, 0.36 and 0.31 mol green ammonium were obtained from protein‐rich brewery spent grain upon supplementation with iron and cobalt, respectively. Metagenomic analysis revealed the high relative abundance of Firmicutes (>90%), of which 85.02% were Clostridium, in mixed metal‐containing reactors. Finally, a significant correlation of dehydrogenase activity with CA and biohydrogen evolution was observed upon metal addition.

Summary: The present study explored the influence of ultrasound on acidogenic fermentation of wastewater for the production of biohydrogen and volatile fatty acids/carboxylic acids. Eight sono-bioreactors underwent ultrasound (20 kHz: 2W and 4W), with an ultrasound duration ranging from 15 min to 30 days, and the formation of acidogenic metabolites. Long-term continuous ultrasonication enhanced biohydrogen and volatile fatty acid production. Specifically, ultrasonication at 4W for 30 days increased biohydrogen production by 3.05-fold compared to the control, corresponding to hydrogen conversion efficiency of 58.4%; enhanced volatile fatty acid production by 2.49-fold; and increased acidification to 76.43%. The observed effect of ultrasound was linked to enrichment with hydrogen-producing acidogens such as Firmicutes, whose proportion increased from 61.9% (control) to 86.22% (4W, 30 days) and 97.53% (2W, 30 days), as well as inhibition of methanogens. This result demonstrates the positive effect of ultrasound on the acidogenic conversion of wastewater to biohydrogen and volatile fatty acid production.

Acetate can be produced from carbon dioxide (CO2) and electricity using bacteria at the cathode of microbial electrosynthesis (MES). This process relies on electrolytically-produced hydrogen (H2). However, the low solubility of H2 can limit the process. Using metal cathodes to generate H2 at a high rate can improve MES. Immobilizing bacteria on the metal cathode can further proliferate the H2 availability to the bacteria. In this study, we investigated the performances of 3D bioprinting of Sporomusa ovata on three metal meshes—copper (Cu), stainless steel (SS), and titanium (Ti), when used individually as a cathode in MES. Bacterial cells were immobilized on the metal using a 3D bioprinter with alginate hydrogel ink. The bioprinted Ti mesh exhibited higher acetate production (53 ± 19 g/m2/d) at −0.8 V vs. Ag/AgCl as compared to other metal cathodes. More than 9 g/L of acetate was achieved with bioprinted Ti, and the least amount was obtained with bioprinted Cu. Although all three metals are known for catalyzing H2 evolution, the lower biocompatibility and chemical stability of Cu hampered its performance. Stable and biocompatible Ti supported the bioprinted S. ovata effectively. Bioprinting of synthetic biofilm on H2-evolving metal cathodes can provide high-performing and robust biocathodes for further application of MES.

Retinal intravascular lipid aggregates were detected in the left eye in a patient with uncontrolled diabetes and very high blood triglycerides. The patient suffered visual loss in the left eye due to retinal ischemia. Optical coherence tomography, fluorescein angiography, infrared fundus photography, and autofluorescence studies of the retina demonstrated unique findings. Slowed choroidal and retinal flow was detected on fluorescein angiography, and a prominent middle layer membrane sign was present on OCT. Intravascular lipid reflectivity was manifest on retinal infrared and autofluorescence imaging. Eventually, insulin and statin therapy proved effective in reversing the vascular lesions, although retinal atrophy finally ensued. This report of a very rare clinical condition provides unique findings on multimodal retinal imaging and confirms the need for prompt insulin and statin therapy in severe/extreme hypertriglyceridemia and dysregulated diabetes. One similar case was reported in the past when multimodal imaging studies of the retina were not available. The lesions described herein should be differentiated from the more frequently encountered lipemia retinalis as they may confer worse prognosis.

Photosynthetic organisms such as eukaryotic microalgae and prokaryotic cyanobacteria synthesize a wide range of valuable chemicals. They are predicted to become efficient and renewable sources for valuable products in the future due to their high biomass synthesis using CO2 and solar energy. Microalgae are producers of several carotenoids including lutein, which is a xanthophyll carotenoid with several health advantages, including the prevention of age-related macular degeneration. Currently, it is extracted on commercial scale from marigold flower petals, however, production from plant sources is highly affected by seasonal variations, requires arable land, and has high production cost. Microalgae, on the other hand, are an ideal alternative for lutein synthesis due to their rapid growth and high biomass and lutein yield. It is, however, necessary to further improve lutein productivity, for a successful transition to commercial production. This article describes lutein biosynthesis in microalgae by using their native biochemical pathways, as well as possible target genes for genetic engineering to enhance lutein production. Understanding the processes behind lipid droplet synthesis in chloroplasts, as well as carotenoid transport across chloroplast membranes and carotenoid esterification, might lead to novel ways to boost lutein levels in microalgae.

Anaerobic digestion (AD) is an environmentally friendly process for recovering low-carbon energy from the breakdown of organic substrates. In recent years, AD has undergone a major paradigm shift, and now the technology is not only considered as a “waste treatment” method and is instead viewed as a key enabler of the future “circular economy” with its potential for resource recovery (low-carbon energy, safe water, and nutrients). Currently, waste-derived biogas from AD is the most affordable and scalable source of renewable energy. Biomethane (upgraded biogas) can serve as a significant renewable and dispatchable energy source for combating the problem of global warming. Acidogenesis, an intermediate step of AD, can produce molecular hydrogen (H2) along with green chemicals/platform chemicals. The use of low-carbon hydrogen as a clean energy source is on the rise throughout the world, and is currently considered a potential alternative energy source that can contribute to the transition to a carbon-neutral future. In order to determine the future trade routes for hydrogen, nations are developing hydrogen policies, and various agreements. Hydrogen produced by biological routes has been found to be suitable due to its potential as a green energy source that is carbon neutral for the developing “Hydrogen Economy”. Recently, hydrogen blended with methane to a specific proportion and known as biohythane/hydrogen-enriched compressed natural gas (HCNG) has emerged as a promising clean fuel that can substantially contribute to an integrated net-zero energy system. This review provides an overview of the current state of fermentative hydrogen and methane production from biogenic waste/wastewater in a biorefinery approach and its utilization in the context of energy transition. The limitations and economic viability of the process, which are crucial challenges associated with biohydrogen/biomethane production, are discussed, along with its utilization.

Abstract Background One of the sustainable development goals focuses on the biomass-based production as a replacement for fossil-based commodities. A novel feedstock with vast potentials is tunicate biomass, which can be pretreated and fermented in a similar way to lignocellulose. Ciona intestinalis is a marine filter feeder that is cultivated to produce fish feed. While the inner tissue body is used for feed production, the surrounding tunic remains as a cellulose-rich by-product, which can be further separated into outer and inner tunic. Ethanol production from organosolv-pretreated whole-tunic biomass was recently validated. The aim of the present study was to evaluate the potential of organosolv pretreated outer-tunic biomass for the production of biofuels and cellobiose that is a disaccharide with prebiotic potential. Results As a result, 41.4 g/L of ethanol by Saccharomyces cerevisiae, corresponding to a 90.2% theoretical yield, was achieved under the optimal conditions when the tunicate biomass was pretreated at 195 °C for 60 min at a liquid-to-solid ratio of 50. In addition, cellobiose production by enzymatic hydrolysis of the pretreated tunicate biomass was demonstrated with a maximum conversion yield of 49.7 wt. %. Conclusions The utilisation of tunicate biomass offers an eco-friendly and sustainable alternative for value-added biofuels and chemicals. The cultivation of tunicate biomass in shallow coastal sea improves the quality of the water and ensures sustainable production of fish feed. Moreover, there is no competition for arable land, which leaves the latter available for food and feed production.

Plant biomass is a magnificent renewable resource for phytochemicals that carry bioactive properties. Ferulic acid (FA) is a hydroxycinnamic acid that is found widespread in plant cell walls, mainly esterified to polysaccharides. It is well known of its strong antioxidant activity, together with numerous properties, such as antimicrobial, anti-inflammatory and neuroprotective effects. This review article provides insights into the potential for valorization of FA as a potent antiviral agent. Its pharmacokinetic properties (absorption, metabolism, distribution and excretion) and the proposed mechanisms that are purported to provide antiviral activity are presented. Novel strategies on extraction and derivatization routes, for enhancing even further the antiviral activity of FA and potentially favor its metabolism, distribution and residence time in the human body, are discussed. These routes may lead to novel high-added value biorefinery pathways to utilize plant biomass toward the production of nutraceuticals as functional foods with attractive bioactive properties, such as enhancing immunity toward viral infections.

BackgroundAdministration of a large amount of contrast volume during chronic total occlusion (CTO) percutaneous coronary intervention (PCI) may lead to contrast-induced nephropathy.MethodsWe examined the association of clinical, angiographic and procedural variables with contrast volume administered during 1330 CTO-PCI procedures performed at 12 experienced United States centers.ResultsTechnical and procedural success was 90% and 88%, respectively, and mean contrast volume was 289 ± 138 mL. Approximately 33% of patients received >320 mL of contrast (high contrast utilization group). On univariable analysis, male gender (P=.01), smoking (P=.01), prior coronary artery bypass graft surgery (P=.04), moderate or severe calcification (P=.01), moderate or severe tortuosity (P=.04), proximal cap ambiguity (P=.01), distal cap at a bifurcation (P

Abstract Background Production of value-added materials from lignocellulosic biomass residues is an emerging sector that has attracted much attention as it offers numerous benefits from an environmental and economical point of view. Non-digestible oligosaccharides represent a group of carbohydrates that are resistant to gastrointestinal digestion, and therefore, they are considered as potential prebiotic candidates. Such oligosaccharides can derive from the biomass cellulose fraction through a controlled enzymatic hydrolysis that eliminates the yield of monomers. Results In the present study, hydrolysis of organosolv-pretreated forest residues (birch and spruce) was tested in the presence of four cellulases (EG5, CBH7, CBH6, EG7) and one accessory enzyme (LPMO). The optimal enzyme combinations were comprised of 20% EG5, 43% CBH7, 22% TtLPMO, 10% PaCbh6a and 5% EG7 in the case of birch and 35% EG5, 45% CBH7, 10% TtLPMO, 10% PaCbh6a and 5% EG7 in the case of spruce, leading to 22.3% and 19.1 wt% cellulose conversion into cellobiose, respectively. Enzymatic hydrolysis was applied on scale-up reactions, and the produced oligosaccharides (consisted of > 90% cellobiose) were recovered and separated from glucose through nanofiltration at optimized temperature (50 °C) and pressure (10 bar) conditions, yielding a final product with cellobiose-to-glucose ratio of 21.1 (birch) and 20.2 (spruce). Cellobiose-rich hydrolysates were tested as fermentative substrates for different lactic acid bacteria. It was shown that they can efficiently stimulate the growth of two Lactobacilli strains. Conclusions Controlled enzymatic hydrolysis with processive cellulases, combined with product recovery and purification, as well as enzyme recycling can potentially support the sustainable production of food-grade oligosaccharides from forest biomass.

Yeasts are widely used in various sectors of biotechnology, from white (industrial) to red (medical) [...]

Polyolefins are semi-crystalline thermoplastic polymers known for their good mechanical properties, low production cost, and chemical resistance. They are amongst the most commonly used plastics, and many polyolefin grades are regarded as engineering polymers. The two main additive manufacturing techniques that can be used to fabricate 3D-printed parts are fused filament fabrication and selective laser sintering. Polyolefins, like polypropylene and polyethylene, can, in principle, be processed with both these techniques. However, the semi-crystalline nature of polyolefins adds complexity to the use of additive manufacturing methods compared to amorphous polymers. First, the crystallization process results in severe shrinkage upon cooling, while the processing temperature and cooling rate affect the mechanical properties and mesoscopic structure of the fabricated parts. In addition, for ultra-high-molecular weight polyolefins, limited chain diffusion is a major obstacle to achieving proper adhesion between adjunct layers. Finally, polyolefins are typically apolar polymers, which reduces the adhesion of the 3D-printed part to the substrate. Notwithstanding these difficulties, it is clear that the successful processing of polyolefins via additive manufacturing techniques would enable the fabrication of high-end engineering products with enormous design flexibility. In addition, additive manufacturing could be utilized for the increased recycling of plastics. This manuscript reviews the work that has been conducted in developing experimental protocols for the additive manufacturing of polyolefins, presenting a comparison between the different approaches with a focus on the use of polyethylene and polypropylene grades. This review is concluded with an outlook for future research to overcome the current challenges that impede the addition of polyolefins to the standard palette of materials processed through additive manufacturing.

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.

Due to the high cost of bioprinters they are not feasible for proof of concept experiments or educational purposes. Furthermore, the more affordable DIY methods all disable the plastic printing capability of the original printer. Here we present an affordable bio-printing modification that is easy to install and maintains the original capabilities of the printer. The modification used mostly 3D printed parts and is based on the popular, open-source Prusa i3 3D printer. The modifications are kept as simple as possible and uses standard slicing software, allowing for installation by less experienced builders. By using disposable syringes and easily sterilizable parts, an aseptic bioprinting setup can be achieved, depending on the environment. It also allows for 2 component printing as well as UV curing. The bio-printing and curing capabilities were shown by printing and curing an artificial biofilm of an electro-active bacteria, Geobacter sulfurreducens, onto a carbon-cloth electrode which was used in a microbial fuel cell.

Cellulases are a group of enzymes responsible for the degradation of cellulose, which is one of the most abundant polymers on Earth. The three main groups of cellulases are endoglucosidases, exoglucosidases, and β-glucosidases; however, the mechanism of induction of these enzymes remains poorly characterized. Cellooligosaccharides are among the main inducers of these enzymes in filamentous fungi, yet it is not clear how their degree of polymerization may affect the strength of induction. In the present study, we investigated the effect of different carbohydrate-based inducers, such as lactose, sophorose, cellooligosaccharides, and xylooligosacharides, characterized by different concentrations and degree of polymerization, on cellulases production by the fungus Fusarium oxysporum f. sp. lycopersici, which is one of the most studied lignocellulose degrading fungi with the ability to consume both cellulose and hemicellulose. Moreover, the effect of carbon source on cellulase induction was assessed by growing the biomass on sucrose or glycerol. Results showed a correlation between induction efficiency and the cellooligosaccharides’ concentration and size, as well as the carbon source available. Specifically, cellotetraose was a better inducer when sucrose was the carbon source, while cellobiose yielded a better result on glycerol. These findings can help optimize industrial cellulase production.

Given an increasing focus on environmental sustainability, microbial oils have been suggested as an alternative to petroleum-based products. However, microbial oil production relies on the use of costly sugar-based feedstocks. Substrate limitation, elevated costs, and risk of contamination have sparked the search for alternatives to sugar-based platforms. Volatile fatty acids are generated during anaerobic digestion of organic waste and are considered a promising substrate for microbial oil production. In the present study, two freshwater and one marine microalga along with two thraustochytrids were evaluated for their potential to produce lipids when cultivated on volatile fatty acids generated from food waste via anaerobic digestion using a membrane bioreactor. Freshwater microalgae Auxenochlorella protothecoides and Chlorella sorokiniana synthesized lipids rich in palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1), and linoleic acid (C18:2). This composition corresponds to that of soybean and jatropha oils, which are used as biodiesel feedstock. Production of added-value polyunsaturated fatty acids (PUFA) mainly omega-3 fatty acids was examined in three different marine strains: Aurantiochytrium sp. T66, Schizochytrium limacinum SR21, and Crypthecodinium cohnii. Only Aurantiochytrium sp. T66 seemed promising, generating 43.19% docosahexaenoic acid (DHA) and 13.56% docosapentaenoic acid (DPA) in total lipids. In summary, we show that A. protothecoides, C. sorokiniana, and Aurantiochytrium sp. T66 can be used for microbial oil production from food waste material.

Ultrasound has many uses, such as in medical imaging, monitoring of crystallization, characterization of emulsions and suspensions, and disruption of cell membranes in the food industry. It can also affect microbial cells by promoting or slowing their growth and increasing the production of some metabolites. However, the exact mechanism explaining the effect of ultrasound has not been identified yet. Most equipment employed to study the effect of ultrasound on microorganisms has been designed for other applications and then only slightly modified. This results in limited control over ultrasound frequency and input power, or pressure distribution in the reactor. The present study aimed to obtain a well-defined reactor by simulating the pressure distribution of a sonobioreactor. Specifically, we optimized a sonotrode to match the bottle frequency and compared it to measured results to verify the accuracy of the simulation. The measured pressure distribution spectrum presented the same overall trend as the simulated spectrum. However, the peaks were much less intense, likely due to non-linear events such as the collapse of cavitation bubbles. To test the application of the sonobioreactor in biological systems, two biotechnologically interesting microorganisms were assessed: an electroactive bacterium, Geobacter sulfurreducens, and a lignocellulose-degrading fungus, Fusarium oxysporum. Sonication resulted in increased malate production by G. sulfurreducens, but no major effect on growth. In comparison, morphology and growth of F. oxysporum were more sensitive to ultrasound intensity. Despite considerable morphological changes at 4 W input power, the growth rate was not adversely affected; however, at 12 W, growth was nearly halted. The above findings indicate that the novel sonobioreactor provides an effective tool for studying the impact of ultrasound on microorganisms.

Abstract Background The aim of this work was to establish a process for the heterotrophic growth of green microalgae using forest biomass hydrolysates. To provide a carbon source for the growth of the green microalgae, two forest biomasses (Norway spruce and silver birch) were pretreated with a hybrid organosolv-steam explosion method, resulting in inhibitor-free pretreated solids with a high cellulose content of 77.9% w/w (birch) and 72% w/w (spruce). Pretreated solids were hydrolyzed using commercial cellulolytic enzymes to produce hydrolysate for the culture of algae. Results The heterotrophic growth of A. protothecoides was assessed using synthetic medium with glucose as carbon source, where the effect of sugar concentration and the carbon-to-nitrogen ratio were optimized, resulting in accumulation of lipids at 5.42 ± 0.32 g/L (64.52 ± 0.53% lipid content) after 5 days of culture on glucose at 20 g/L. The use of birch and spruce hydrolysates was favorable for the growth and lipid accumulation of the algae, resulting in lipid production of 5.65 ± 0.21 g/L (66 ± 0.33% lipid content) and 5.28 ± 0.17 g/L (63.08 ± 0.71% lipid content) when grown on birch and spruce, respectively, after only 120 h of cultivation. Conclusions To the best of our knowledge, this is the first report of using organosolv pretreated wood biomass hydrolysates for the growth and lipid production of microalgae in the literature. The pretreatment process used in this study provided high saccharification of biomass without the presence of inhibitors. Moreover, the lipid profile of this microalga showed similar contents to vegetable oils which improve the biodiesel properties.

Three novel feruloyl esterases (Fae125, Fae7262 and Fae68) from Talaromyces wortmannii overexpressed in the C1 platform were evaluated for the transesterification of vinyl ferulate with two acceptors of different size and lipophilicity (prenol and L-arabinose) in detergentless microemulsions. The effect of reaction conditions such as the microemulsion composition, the substrate concentration, the enzyme load, the pH, the temperature and the agitation were investigated. The type A Fae125 belonging to the subfamily 5 (SF5) of phylogenetic classification showed highest yields for the synthesis of both products after optimization of reaction conditions: 81.8% for prenyl ferulate and 33.0% for L-arabinose ferulate. After optimization, an 8-fold increase in the yield and a 12-fold increase in selectivity were achieved for the synthesis of prenyl ferulate.

The use of residual biomass for bioconversions makes it possible to decrease the output of fossil-based chemicals and pursue a greener economy. While the use of lignocellulosic material as sustainable feedstock has been tried at pilot scale, industrial production is not yet economically feasible, requiring further technology and feedstock optimization. The aim of this study was to examine the feasibility of replacing woodchips with residual sawdust in biorefinery applications. Woodchips can be used in value-added processes such as paper pulp production, whereas sawdust is currently used mainly for combustion. The main advantages of sawdust are its large supply and a particle size sufficiently small for the pretreatment process. Whereas, the main challenge is the higher complexity of the lignocellulosic biomass, as it can contain small amounts of bark and cambium. Here, we studied the fractionation of birch sawdust by organosolv pretreatment at two different temperatures and for two different durations. We evaluated the efficiency of fractionation into the three main fractions: lignin, cellulose, and hemicellulose. The cellulose content in pretreated biomass was as high as 69.2%, which was nearly double the amount in untreated biomass. The obtained lignin was of high purity, with a maximum 4.5% of contaminating sugars. Subsequent evaluation of the susceptibility of pretreated solids to enzymatic saccharification revealed glucose yields ranging from 75% to 90% after 48 h but reaching 100.0% under the best conditions. In summary, birch sawdust can be successfully utilized as a feedstock for organosolv fractionation and replace woodchips to simplify and lower the costs of biorefinery processes.

In this study, formaldehyde-free bioresin adhesives were synthesised from lignin and tannin, which were obtained from softwood bark. The extraction was done via organosolv treatment and hot water extraction, respectively. A non-volatile, non-toxic aldehyde, glyoxal, was used as a substitute for formaldehyde in order to modify the chemical structure of both the lignin and tannin. The glyoxal modification reaction was confirmed by ATR–FTIR spectroscopy. Three different resin formulations were prepared using modified lignin along with the modified tannin. The thermal properties of the modified lignin, tannin, and the bioresins were assessed by DSC and TGA. When the bioresins were cured at a high temperature (200 °C) by compression moulding, they exhibited higher thermal stability as well as an enhanced degree of cross-linking compared to the low temperature-cured bioresins. The thermal properties of the resins were strongly affected by the compositions of the resins as well as the curing temperatures.

Background: Many buildings in Egypt e.g. museums, mosques and churches, do not possess controlled environments for minimizing the risks of damage of wooden artifacts due to the growth of fungi. Fungal damage usually appears as change in wood color, appearance of stains, and sometimes deformation of wooden surfaces. In this study we focused on the effect that some fungi exert on the properties of wooden artifacts and evaluated the effectiveness of different concentrations of chitosan on their protection against damage by mold fungi. Results: Samples were collected from different monuments and environments, and fungi growing on them were isolated and identified. The isolated Penicillium chrysogenum, Aspergillus flavus and Aspergillus niger strains were used for the infestation of new pitch pine samples. The results revealed that the lightness of samples infected with any of the tested fungi decreased with increasing incubation times. XRD analysis showed that the crystallinity of incubated samples treated individually with the different concentrations of chitosan was lower than the crystallinity of infected samples. The crystallinity index measured by the first and the second method decreased after the first and second months but increased after the third and fourth months. This may due to the reducing of amorphous part by enzymes or acids produced by fungi in wooden samples. Conclusions: The growth of fungi on the treated wood samples decreased with increasing the concentration of chitosan. Hence, it was demonstrated that chitosan prevented fungal growth, and its use could be recommended for the protection of archeological wooden artifacts.

The achievement of the long-term national energy targets in Greece for large-scale integration of wind and solar energy may be facilitated by the development of hydro-pumped storage projects. In light of the above, technical aspects related with the operation of the Greek power system and its ability to absorb renewable energy are analyzed in connection with the role of hydro-pumped storage and relative economic aspects. The aim of this work is to assess the potential contribution of hydro-pumped storage projects and estimate the capacity magnitude order to support large-scale wind and photovoltaic (PV) integration in Greece. For this purpose, scenarios for the Greek power system with focus on Wind and PV development, in conjunction with hydro-pumped storage capacity, are developed, and results for current situation and reference years 2030 and 2050 are presented. For the simulation, among others, high resolution mesoscale wind data for a typical year in the whole Greek territory are used for the steady state simulation of the Greek power system, in order to better estimate the power that could be generated from installed wind turbines, taking into consideration technical characteristics of a typical commercial wind turbine. Results indicate the need of gradual development of hydro-pumped storage in parallel with the large-scale integration of wind and PV capacity into the Greek power system. In addition, the feasibility of the examined scenarios is supported from the low cost of wind and PV generation. In the case of Greece, thanks to the complex morphology and hydraulic conditions of the country, hydro-pumped storage composes an efficient and low-cost storage solution.