Search Results (43)

Human skin lipids form interconnected pools that support barrier integrity, immune balance, and interactions with the environment. The stratum corneum barrier is built from an ordered mix of ceramides, cholesterol, and long-chain free fatty acids, while sebaceous lipids and their breakdown products shape surface properties and the skin microbiome. Hexadecenoic fatty acids are key at this interface. Palmitoleic acid (cis-9 16:1; 16:1 n−7, POA) is enriched in viable epidermis and remains detectable in stratum corneum lipids, whereas its isomer sapienic acid (cis-6 16:1; 16:1 n−10) predominates in human sebum. Together, they influence membrane organization, lipid fluidity, and antimicrobial defense. This mini-review outlines skin lipid composition and function with a focus on POA and then summarizes experimental and preclinical topical evidence suggesting antimicrobial effects, enhanced lubrication properties, protection from oxidative and ultraviolet B (UVB) injury, and enhanced wound repair. It also reviews early clinical findings from oral POA supplementation trials reporting improved hydration, barrier function, and markers of photo-oxidative aging, with exploratory signals for acne in a multi-nutrient regimen. Major POA sources include sea buckthorn pulp oil, macadamia and avocado oils, selected marine oils, ruminant fats, and emerging fermentation-derived products. Robust mechanistic human studies are still needed to define optimal dosing, formulations, and indications. Full article

Biohydrogen, a low-carbon footprint technology, can play a significant role in decarbonizing the energy system. It uses existing infrastructure, is easily transportable, and produces no greenhouse gas emissions. Four technologies can be used to produce biohydrogen: photosynthetic biohydrogen, dark fermentation (DF), photo-fermentation, and microbial electrolysis cells (MECs). DF produces more biohydrogen and is flexible with organic substrates, making it a sustainable method of waste repurposing. However, low achievable biohydrogen yields are a common issue. To overcome this, catalytic mechanisms, including enzymatic systems such as [Fe-Fe]- and [Ni-Fe]-hydrogenases in DF and electroactive microbial consortia in MECs, alongside advanced electrode catalysts which collectively surmount thermodynamic and kinetic constraints, and the two stage system, such as DF connection to photo-fermentation and anaerobic digestion (AD) to microbial electrolysis cells (MECs), have been investigated. MECs can generate biohydrogen at better yields by using sugars or organic acids, and combining DF and MEC technologies could improve biohydrogen production. As such, this review highlights the challenges and possible solutions for coupling DF–MEC while also offering knowledge regarding the technical and microbiological aspects. Full article

This study explores the sequential valorization of orange peel waste (OPW) through photo-fermentation using real dark fermentation effluents (DFE) as substrates for hydrogen production using Rhodobacter capsulatus B10. Three DFE types—differing in prior biocompound extraction method—and their concentrations at three levels (25, 35, and 45%) were evaluated. The highest hydrogen yield (126.5 mL H₂ g⁻¹ VFA) was achieved with DFE derived from essential oil-extracted OPW at a concentration of 25%. The highest DFE concentration reduced the hydrogen yield due to intensified medium opacity and potential substrate inhibition. Kinetic modeling revealed that the Modified Gompertz and T_i-Gompertz models best described hydrogen production dynamics. This study presents the first evidence of hydrogen production via photo-fermentation using real effluents derived from OPW processing, demonstrating a novel route for citrus waste reuse within a biorefinery framework. These findings underscore the innovation and relevance of integrating waste valorization with clean energy production, while also identifying key operational challenges to be addressed. Full article

Pisco is an emblematic spirit in Peru and Chile, made from fermented grapes, gaining growing scientific interest over the last two decades. This study aimed to map 20 years of research on Pisco through a systematic bibliometric review. A search was conducted in the Scopus database covering the period from 2004 to 2024, applying the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology for the transparent selection of scientific articles. The search strategy considered titles, abstracts, and keywords, using the terms “Pisco” and “schnapps”, excluding unrelated fields such as geology (basin, seismic, fossil). The initial search yielded 360 records. After removing non-original articles (books, book chapters, conference papers, and reviews), 101 articles remained. A further screening excluded irrelevant studies (e.g., those referring to the city of Pisco rather than the beverage), resulting in 78 articles included for final analysis. It was observed that 19% of the studies focus on the history, culture, and appellation of origin; 14% on environmental sustainability; 10% on innovation and quality; and 9% on the bioactive properties of by-products. Other areas include extraction technologies (9%), distillation process modeling (8%), and marketing and economics (8%), among others. Recent trends are related to clean production practices. Thus, Pisco by-products and their components can be exploited by applying technologies such as supercritical fluids, drying, and biofilms, while, for waste management, the processes of composting, solar photo-Fenton, and ozonation can be applied. Moreover, it is important to highlight that the valorization of Pisco by-products opens opportunities for translation into the market, particularly in developing cosmetics, nutritional supplements, and bio-packaging materials, contributing to sustainability and innovation in new industries. However, a more holistic view is still needed in Pisco research. These findings suggest that future research should prioritize the integration of consumer-based sensory evaluations and sustainable production innovations to optimize Pisco’s quality, enhance market acceptance, and promote environmentally responsible industry practices. Full article

This study explored innovative approaches to produce ethanol and xylitol from sugarcane bagasse using a hydrodynamic cavitation-assisted photo-Fenton process as the pretreatment, and yeast co-culture for hydrolysate fermentation. Pretreatment conditions were optimized (20 mg/L of iron sulfate, pH 5.0, and reaction time of 14 min) resulting in glucan and xylan hydrolysis yields of 96% and 89%, respectively. The hydrolysate produced under these conditions was fermented using a co-culture of Saccharomyces cerevisiae IR2 (an ethanol-producing strain) and Candida tropicalis UFMGBX12 (a xylitol-producing strain). Optimal co-culture conditions consisted of using an inoculum concentration of 1.5 g/L for each yeast strain. After 36 h of fermentation, ethanol and xylitol concentrations reached 20 g/L and 13 g/L, respectively. These results demonstrate the potential of combining hydrodynamic cavitation-assisted photo-Fenton pretreatment with co-culture fermentation to simultaneously produce ethanol and xylitol. This strategy presents a promising approach for enhancing the efficiency of lignocellulosic biorefineries. Full article

Chaga (Inonotus obliquus) is an increasingly used natural product in botanical dietary supplements, valued for its bioactive compounds. However, inconsistent standardized analytical methods raise concerns over product authenticity, mislabeling, and quality control. This study employs a multi-analytical approach to differentiate wildcrafted chaga canker from North American chaga dietary supplements, particularly those containing mycelia fermented grain products. High-Performance Thin-Layer Chromatography (HPTLC), Liquid Chromatography with Evaporative Light Scattering Detection (LC-ELSD) or Photo/Diode Array Detection (LC-PDA/DAD), Liquid Chromatography-Quadrupole Time-of-Flight Mass Spectrometry (LC-QToF-MS), Nuclear Magnetic Resonance (NMR) spectroscopy, UV-Vis spectrophotometry, and iodine-starch assays were used to evaluate key markers, including triterpenoids, polysaccharides, and melanin. Whole chaga canker contained triterpenoids (inotodiol, trametenolic acid) and phenolics, like osmundacetone, while melanin absorbance at 500 nm differentiated it from fermented grain products. β-Glucan quantification and iodine-starch assays confirmed starch-rich composition in fermented grains and its absence in authentic chaga canker. NMR fingerprinting and LC-QToF-MS metabolomics demonstrated stark compositional deviations between wildcrafted chaga canker, I. obliquus mycelium, and fermented grain products. By integrating complementary techniques, we establish a framework that can reliably distinguish genuine chaga canker from misrepresented products, ensuring consumer safety and fostering trust in the functional mushroom, canker, and mycelium markets. Full article

Waste-based sustainable solutions proposed by scientific and industrial communities for energy production are an approach that can respond to the growing concerns regarding climate change and fossil resources depletion. This study investigates a two-phase bioprocess combining dark fermentation (DF) and photo-fermentation (PF) to enhance hydrogen yield while anaerobically treating urban organic food waste and sewage sludge. A key objective was to assess the effect of waste composition and temperature on hydrogen accumulation, with particular attention to the fermentation product and the role of zeolite in improving process efficiency. In the DF stage, the addition of zeolite significantly enhanced hydrogen production by increasing microbial activity and improving substrate bioavailability. As a result, hydrogen production increased up to 27.3 mmol H₂/(L d) under thermophilic conditions. After the suspended solids were removed from the dark fermentation broth, a photo-fermentation step driven by a pure strain of Rhodopseudomonas palustris was performed under permanent IR light and different substrate-to-inoculum [S/I] ratios. The maximum hydrogen production rate was 9.33 mmol H₂/(L d), when R. palustris was inoculated at the lowest [S/I] ratio (<20 COD/COD) and with 0.5 g VSS/L as the initial concentration. This condition in the photo-fermentation process led to an increase in the hydrogen yield up to 35% compared to values obtained from dark fermentation alone. Full article

The growth and metabolism of photosynthetic bacteria play a significant role in the efficiency of substrate and energy conversion in photo-fermentation biohydrogen production (PFHP). In this paper, the influence of different concentrations of L-alanine (0.3–1.2 g/L), L-leucine (0.6–1.5 g/L), and L-serine (1–2.5 g/L) on the PFHP and microbial metabolism were investigated. The results showed that sole additions of L-alanine at 0.6 g/L, L-leucine at 0.9 g/L, and L-serine at 1.5 g/L to the PFHP could enhance the cumulative biohydrogen production to 260 ± 4.01 mL (39.04% increase), 267 ± 4.27 mL (42.78% increase), and 248 ± 3.97 mL (32.62% increase), respectively. An analysis of the scatter matrix plots indicated that three amino acid additives play a key role in increasing hydrogen production. This study helps to further explore the effect of amino acid-based additives on PFHP. Full article

In the last five years, the use of hydrogen as an energy carrier has received rising attention because it can be used in internal combustion and jet engines, and it can even generate electricity in fuel cells. The scope of this work was to critically review the methods of H₂ production from renewable and non-renewable sources, with a focus on bio-H₂ production from the perennial grass giant reed (Arundo donax L.) due to its outstanding biomass yield. This lignocellulosic biomass appears as a promising feedstock for bio-H₂ production, with a higher yield in dark fermentation than photo-fermentation (217 vs. 87 mL H₂ g⁻¹ volatile solids on average). The H₂ production can reach 202 m³ Mg⁻¹ of giant reed dry matter. Assuming the average giant reed dry biomass yield (30.3 Mg ha⁻¹ y⁻¹), the attainable H₂ yield could be 6060 m³ ha⁻¹ y⁻¹. A synthetic but comprehensive review of methods of H₂ production from non-renewable sources is first presented, and then a more detailed analysis of renewable sources is discussed with emphasis on giant reed. Perspectives and challenges of bio-H₂ production, including storage and transportation, are also discussed. Full article

Sustainable waste management strategies are urgently needed due to an increasing global population and increased waste production. In this context, biorefineries have recently emerged as a promising approach to valorize waste streams and supply a broad range of products. This study presents the process model and life cycle assessment (LCA) of a biorefinery concept using a novel biochemical method, a so-called “dark photosynthesis” conversion. This process is coupled to a photo-fermentation using microalgae. Overall, the biorefinery concept can produce hydrogen, lutein, β-carotene, and proteins for animal feed. Apple pomace from apple juice production is used as feedstock for the primary conversion step. A process model was created with the process simulation software Aspen Plus^® using experimental and literature data. Results from this model were then used in an LCA. The environmental impacts of the proposed biorefinery concept are relatively high, showing the need for process optimization in several areas. Energy system integration, stream recycling, and higher hydrogen yields are recognized as especially important for improving the environmental performance of this concept. Despite these findings, the model shows the feasibility of implementing the biochemical conversion technologies in a biorefinery concept for effectively utilizing residue streams. Full article

Metabolites resulting from the bacterial fermentation of dietary fibers, such as short-chain fatty acids, especially butyrate, play important roles in maintaining gut health and regulating various biological effects in the skin. However, butyrate is underutilized due to its unpleasant odor. To circumvent this organoleptic unfavorable property, phenylalanine butyramide (PBA), a butyrate precursor, has been synthesized and is currently available on the market. We evaluated the inhibition of mushroom tyrosinase by butyrate and PBA through in vitro assays, finding IC₅₀ values of 34.7 mM and 120.3 mM, respectively. Docking calculations using a homology model of human tyrosinase identified a putative binding mode of PBA into the catalytic site. The anti-aging and anti-spot efficacy of topical PBA was evaluated in a randomized, double-blind, parallel-arm, placebo-controlled clinical trial involving 43 women affected by photo-damage. The results of this study showed that PBA significantly improved skin conditions compared to the placebo and was well tolerated. Specifically, PBA demonstrated strong skin depigmenting activity on both UV and brown spots (UV: −12.7% and −9.9%, Bs: −20.8% and −17.7% after 15 and 30 days, respectively, p < 0.001). Moreover, PBA brightened and lightened the skin (ITA°: +12% and 13% after 15 and 30 days, respectively, p < 0.001). Finally, PBA significantly improved skin elasticity (Ua/Uf: +12.4% and +32.3% after 15 and 30 days, respectively, p < 0.001) and firmness (Uf: −3.2% and −14.9% after 15 and 30 days, respectively, p < 0.01). Full article

This study evaluated the feasibility of contextually producing hydrogen, microbial proteins, and polyhydroxybutyrate (PHB) using a mixed culture of purple phototrophic bacteria biomass under photo fermentative conditions. To this end, three consecutive batch tests were conducted to analyze the biomass growth curve and to explore the potential for optimizing the production process. Experimental findings indicated that inoculating reactors with microorganisms from the exponential growth phase reduced the duration of the process. Furthermore, the most effective approach for simultaneous hydrogen production and the valorization of microbial biomass was found when conducting the process during the exponential growth phase of the biomass. At this stage, achieved after 3 days of fermentation, the productivities of hydrogen, PHB, and microbial proteins were measured at 63.63 L/m³ d, 0.049 kg/m³ d, and 0.045 kg/m³ d, respectively. The biomass composition comprised a total intracellular compound percentage of 56%, with 27% representing PHB and 29% representing proteins. Under these conditions, the estimated daily revenue was maximized, amounting to 0.6 $/m³ d. Full article

Annually, the food industry generates large amounts of waste and by-products, causing serious problems in their management and final disposal. In particular, by-products are mainly recovered as livestock feed. A most appealing strategy to valorize them has herein been investigated, through polyhydroxyalkanoate (PHA) production. In this view, a stream rich in volatile fatty acids deriving from the acidogenic fermentation of reground pasta (RP), a farinaceous food-industry by-product, was used as a carbon source for PHA production with a phototrophic purple bacteria (PPB) consortium. PPB are very versatile organisms that present a unique metabolism allowing them to adapt to a variety of environmental conditions. The PPB-PHA enrichment phase was performed in a lab-scale semi-continuous photo-bioreactor under a permanent carbon feast regime, with organic loading rate (OLR) increments from 14 to 19 mmolC/Ld. The results showed that the fermented RP solution composition (with 23.4% of HV precursors on a COD basis) was suitable for the PHBHV copolymer production, with the PPB consortium being capable of reaching a very high content in the hydroxyvalerate (HV) monomer, with a maximum of 60% (gHV/gPHA). Regarding the PHA accumulation stage where the light intensity was increased up to 20.2 W/L, a further increase in the culture PHA content by 76% after 12 h was obtained. Overall, these results open the possibility of valorizing food-industry by-products through the development of a biocatalytic process for PHA production with PPB, thus making the overall approach more sustainable from a green perspective. Full article

Advancements in biological wastewater treatment with sustainable and circularity approaches have a wide scope of application. Biological wastewater treatment is widely used to remove/recover organic pollutants and nutrients from a diverse wastewater spectrum. However, conventional biological processes face challenges, such as low efficiency, high energy consumption, and the generation of excess sludge. To overcome these limitations, integrated strategies that combine biological treatment with other physical, chemical, or biological methods have been developed and applied in recent years. This review emphasizes the recent advances in integrated strategies for biological wastewater treatment, focusing on their mechanisms, benefits, challenges, and prospects. The review also discusses the potential applications of integrated strategies for diverse wastewater treatment towards green energy and resource recovery, along with low-carbon fuel production. Biological treatment methods, viz., bioremediation, electro-coagulation, electro-flocculation, electro-Fenton, advanced oxidation, electro-oxidation, bioelectrochemical systems, and photo-remediation, are summarized with respect to non-genetically modified metabolic reactions. Different conducting materials (CMs) play a significant role in mass/charge transfer metabolic processes and aid in enhancing fermentation rates. Carbon, metal, and nano-based CMs hybridization in different processes provide favorable conditions to the fermentative biocatalyst and trigger their activity towards overcoming the limitations of the conventional process. The emerging field of nanotechnology provides novel additional opportunities to surmount the constraints of conventional process for enhanced waste remediation and resource valorization. Holistically, integrated strategies are promising alternatives for improving the efficiency and effectiveness of biological wastewater treatment while also contributing to the circular economy and environmental protection. Full article

Photo-fermentation is an efficient hydrogen production pathway in which purple non-sulfur bacteria (PNSB) play an active role and produce hydrogen as a part of their metabolism under optimal conditions. These bacteria work under the influence of light to advance their metabolism and use various substrates, such as simple sugars and volatile fatty acids, to produce hydrogen. This article presents a comparative review of several bacterial strains that have been efficiently used to produce hydrogen by photo-fermentation under different optimized conditions, including the substrate, its concentration, type and capacity of the bioreactor, light sources and intensities, and process conditions to achieve the maximum biohydrogen production rate. The analysis showed that the Rhodopseudomonas palustris is the main bacterium used for hydrogen production, with a maximum hydrogen production rate of 3.2 mM/h using 27.8 mM of glucose in a 165 mL serum bottle and 3.23 mM/h using 50 mM of glycerol at pH 7, followed by Rhodobacter sphaeroides, which gave a hydrogen production rate as high as 8.7 mM/h, using 40 mM of lactic acid, pH 7, and 30 °C temperature in a single-walled glass bioreactor. However, it is not preferred over R. palustris due to its versatile metabolism and ability to use an alternative mode if the conditions are not carefully adjusted, which can be a problem in hydrogen production. Full article