Use of fermented spent coffee grounds as a substrate supplement for rearing black soldier fly larvae, Hermetia illucens (L), (Diptera: Stratiomyidae).

Background: Spent coffee grounds (SCG), an increasingly abundant waste product with environmental disposal problems, has been used as a dietary supplement for many animals and have the potential to be used as a dietary supplement for black soldier fly (BSF) larvae; however, its effective use is still under scrutiny. To date, no studies have considered the use of SCG after microbial fermentation (fSCG) and its effects on BSF life history. Methods: A mixture of fruit and vegetable pulp residue supplemented with one of six different fSCG percentages (0%, 20%, 40%, 60%, 80%, and 100% by weight) were provided as a diet substrate in order to evaluate the effect of the fSCG quantity on BSF growth, yield, and conversion ability. Results: The addition of fSCG to the pulp diet prolonged larval development times, while 100% fSCG affected the larval survival rate and resulted in a male-biased adult sex ratio. The 20-40% fSCG and 40-60% fSCG treatments supported the largest prepupal and mature larval sizes, respectively. The highest waste reduction efficiency and feed conversion rate by BSF larvae was found with 20% fSCG, similar to the control (0% fSCG). Discussion: From the short rearing time, high yield, and high bioconversion efficiency, a 20% fSCG supplementation of the mixed pulp was recommended for rearing BSF larvae. These data are valuable for coffee by-product waste management in urban areas.

Towards the sustainable and circular bioeconomy: Insights on spent coffee grounds valorization.

Discovered in Ethiopia, coffee became a popular beverage in Asia, Europe, Latin America, Australia, Africa and the North America as a drink after water and the largest goods after petroleum. However, the coffee industry generates a huge biomass as its byproducts of which the spent coffee grounds (SCG) is concerning, especially in the production chain away from the farm. Therefore, the valorization and revalorization of the SCG has a huge impact on the socioeconomic and environmental sustainability of the industry, up to the realization of the circular bioeconomy. With the advancing biorefinery concept, even an almost complete recovery of the SCG is reported at an experimental level. Such kind of studies increased with time following the action of the Sustainable Development Goals by the United Nations Development Program promulgated in 2015. The current review highlights on the background, socioeconomic, environmental contexts of coffee production and the SCG valorization and revalorization studies. Refereeing to 154 screened articles published in over 30 years' time, the SCG revalorization efforts and its integrated biorefinery as a green management approach are uniquely addressed. Plenty of studies have reported the production of bio-products from the SCG, such as the derivation of adsorbents, biochar, bioethanol, biogas, biodiesel, bio-oil, compost, construction material aggregates, cosmetics, electricity and food ingredients. In conclusion, the recovery potential of the SCG is promising and can substantially contribute to a sustainable and green bioeconomy. Nevertheless, the recovery of bioactive materials through SCG fermentation is still lacking. Most studies are conducted on a lab scale, which needs to be piloted and commissioned. Furthermore, the link between climate change and variability vis-à-vis the sustainable management of the SCG remains unaddressed.

A state-of-the-art review on spent coffee ground (SCG) pyrolysis for future biorefinery.

Coffee is a globally consumed beverage that produces a substantial amount of valuable organic waste known as spent coffee grounds (SCG). Although SCG is a non-edible biomass, research initiatives focused on valorizing/utilizing its organic content, protecting the environment, and reducing the high oxygen demand required for its natural degradation. The integration with biorefinery in general and with pyrolysis process in specific is considerered the most successful solid waste management strategy of SCG that produce energy and high-value products. This paper aims at providing a quantitative analysis and discussion of research work done over the last 20 years on SCG as a feedstock in the circular bioeconomy (CBE). Management stratigies of SCG have been thoroughly reviewed and pyrolysis process has been explored as a novel technology in CBE. Results revealed that explored articles belong to Chemical, physical., biological and environmental science branches, with Energy & Fuels as the most reporting themes. Published works correlate SCG to renewable energy, biofuel, and bio-oil, with pyrolysis as a potential valorization approach. Literature review showed that only one study focused on the pyrolysis of defatted spent coffee grounds (DSCG). The insightful conclusions of this paper could assist in proposing several paths to more economically valorization of SCG through biorefinery, where extracted oil can be converted to biofuels or value-added goods. It was highlighted the importance of focusing on the coupling of SCG with CBE as solid waste managment strategy.

Improving the Recovery of Phenolic Compounds from Spent Coffee Grounds (SCG) by Environmentally Friendly Extraction Techniques.

The aim of this study was to investigate and compare the effects of different extraction techniques (high hydrostatic pressure-assisted extraction (HHPE), ultrasound-assisted extraction (UAE), and classical solvent extraction (CSE)) on phenolic compounds from spent coffee grounds (SCG). Different HHPE parameters (300, 400 and 500 MPa at 25 °C for 5, 10 and 15 min) and UAE parameters (40%, 50%, and 60% amplitude at 25 °C for 5, 10 and 15 min) were used. These techniques were compared with CSE (at 50 °C for 30 min) according to total phenolic content (TPC), antioxidant activity (AA), high-performance liquid chromatography (HPLC), scanning electron microscopy (SEM), and infrared (IR) spectroscopy. The results showed that eco-friendly techniques increased the TPC and AA compared to CSE and morphological changes were verified by SEM results. Furthermore, chlorogenic and caffeic acid were also quantified by using HPLC. Chlorogenic acid was found as the main phenolic compound in spent coffee grounds (SCG). The highest chlorogenic acid was detected as 85.0 ± 0.6 mg/kg FW with UAE at 60% amplitude for 15 min. In brief, for the extraction of phenolic compounds from waste SCG eco-friendly techniques such as HHPE and/or UAE were more convenient than CSE.

Anabolism of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) by Cupriavidus necator DSM 545 from spent coffee grounds oil.

Oil extracted from spent coffee grounds (SCG) [yield 16.8 % (w/w)] was discovered to be a highly suitable carbon substrate for the biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3 HV)] copolymers by Cupriavidus necator DSM 545 in the absence of any traditional 3 HV precursors. Cells cultivated in a 3 L bioreactor (batch) reached a total biomass concentration of 8.9 g L-1 with a P(3HB-co-3 HV) (6.8 mol% 3 HV) content of 89.6 % (w/w). In contrast, cells grown on sunflower oil reached a total biomass concentration of 9.4 gL-1 with a P(3HB-co-3 HV) (0.2 mol% 3 HV) content of 88.1 % (w/w). It is proposed that the organism could synthesize 3 HV monomers from succinyl CoA, an intermediate of the tricarboxylic acid (TCA) cycle, via the succinate-propionate metabolic pathway.

Experimental and feasibility study of spent coffee grounds upscaling via pyrolysis towards proposing an eco-social innovation circular economy solution.

There is a need for eco-social business models in the food waste sector that are more cascading and circular-based, while having economic, environmental and social benefits. The aim of this study is to bring insights and data of spent coffee grounds large-scale slow pyrolysis, to seize new opportunities for eco-innovative solutions in the circular economy, by identifying upcycling opportunities for resource recovery of this waste. First, an experimental study was conducted, and a set of pyrolysis experiments were carried out at a temperature range from 450 to 750 °C, with a heating rate of 50°/s, under helium atmosphere, to explore the products' yields and the best process' conditions. Second, an economic study was conducted for a standalone pyrolysis plant fueled with the spent coffee grounds streams from coffee shops of a city with 150,000 inhabitants, in central Greece, aiming at the cost and the profitability of the endeavor estimation. The calculations were based on the features of a slow pyrolysis rotary kiln technology designed at Aristotle University, and co-developed with an Irish company, under the funding of an EU LIFE+ project. For an estimated capacity of 2566 t/yr of SCG, the revenue of the endeavor was calculated at 47€/t of SCG. The economic indicators ROI and POT (ROI = 0.24, POT = 2.6), are very positive, suggesting pyrolysis of SCG as an efficient circular economy management solution, providing an eco-social innovation business in the coffee shop industry, engaging also consumers in the circular economy.

Spent coffee grounds as supporting materials to produce bio-composite PCM with natural waxes.

Novel kinds of bio composite Phase change materials were prepared by the use of bio-wastes. Of the by-products, coffee wastes, which is currently consumed and abandoned as coffee as a drink, was used as the supporting material for PCM. It was found through chemical composition of FTIR of SCBW, SCPW, SCGW and that the coffee wastes were effectively vacuum impregnated into each natural wax. As a result of TGA, the thermal stability of SCBW, SCPW, SCGW and SCNW was checked. In addition, the DSC results were used to determine the heat storage performance of each material. Micro-morphological analysis with FE-SEM showed whether the impregnation was successful. The use of bio-compatible PCM by-products is economical as well as environmentally friendly and is sufficient for building applications in terms of thermal performance compared to other bio-composites.

Converting environmental risks to benefits by using spent coffee grounds (SCG) as a valuable resource.

Coffee is perhaps one of the most vital ingredients in humans' daily life in modern world. However, this causes the production of million tons of relevant wastes, i.e., plastic cups, aluminum capsules, coffee chaff (silver skin), and spent coffee grounds (SCG), all thrown untreated into landfills. It is estimated that 1 kg of instant coffee generates around 2 kg of wet SCG; a relatively unique organic waste stream, with little to no contamination, separated directly in the source by the coffee shops. The produced waste has been under researchers' microscope as a useful feedstock for a number of promising applications. SCG is considered a valuable, nutrients rich source of bioactive compounds (e.g., phenolics, flavonoids, carotenoids, lipids, chlorogenic and protocatechuic acid, melanoidins, diterpenes, xanthines, vitamin precursors, etc.) and a useful resource material in other processes (e.g., soil improver and compost, heavy metals absorbent, biochar, biodiesel, pellets, cosmetics, food, and deodorization products). This paper aims to provide a holistic approach for the SCG waste management, highlighting a series of processes and applications in environmental solutions, food industry, and agricultural sector. Thus, the latest developments and approaches of SCG waste management are reviewed and discussed.

Spent coffee ground as a new bulking agent for accelerated biodrying of dewatered sludge.

The feasibility of using spent coffee ground (SCG) as a new bulking agent for biodrying of dewatered sludge (DS) was investigated in comparison with two other frequently-used bulking agents, air-dried sludge (AS) and sawdust (SD). Results showed that the moisture contents (MC) of 16-day DS biodrying with AS (Trial A), SCG (Trial B) and SD (Trial C) decreased from 70.14 wt%, 68.25 wt% and 71.63 wt% to 59.12 wt%, 41.35 wt% and 57.69 wt%, respectively. In case of Trial B, the MC rapidly decreased to 46.16 wt% with the highest water removal (70.87%) within 8 days because of the longest high-temperature period (5.8 days). Further studies indicated that the abundant biodegradable volatile solids (BVS) and high dissolved organic matter (DOM) contents in SCG were the main driving forces for water removal. According to pyrosequencing data, Firmicutes, most of which were recognized as thermophiles, was rapidly enriched on Day 8 and became the dominant phylum in Trial B. Four thermophilic genera, Bacillus, Ureibacillus, Geobacillus and Thermobifida, which can produce thermostable hydrolytic extracellular enzymes, were the most abundant in Trial B, indicating that these thermophilic bacteria evolved during the long high-temperature period enhanced the biodegradation of BVS in SCG. The 8-day biodried product of Trial B was demonstrated to be an excellent solid fuel with low heating value (LHV) of 9284 kJ kg-1, which was 2.1 and 1.8 times those of biodried products with AS and SD, respectively. Thus SCG was found to be an excellent bulking agent accelerating DS biodrying and producing a solid fuel with a high calorific value.

Wet in situ transesterification of spent coffee grounds with supercritical methanol for the production of biodiesel.

This work introduces biodiesel production from wet spent coffee grounds (SCGs) with supercritical methanol without any pre-drying process. Supercritical methanol and subcritical water effectively produced biodiesel via in situ transesterification by inducing more porous SCG and enhancing the efficiency of lipid extraction and conversion. It was also found that space loading was one of the critical factors for biodiesel production. An optimal biodiesel yield of 10.17 wt% of dry SCG mass (86.33 w/w% of esterifiable lipids in SCG) was obtained at reaction conditions of 270 °C, 90 bars, methanol to wet SCG ratio 5:1, space loading 58.4 ml/g and reaction time 20 min. Direct use of wet SCG waste as feedstock for supercritical biodiesel production eliminates the conventional dying process and the need of catalyst and also reduces environmental problems caused by landfill accumulation.

Solvo-thermal in situ transesterification of wet spent coffee grounds for the production of biodiesel.

This work addresses non-catalytic biodiesel production from spent coffee ground (SCG) by integrating solvo-thermal effect of 1,2-dichloroethane (DCE) with in situ transesterification over 160 °C. The SCG water content has a positive effect on the DCE hydrolysis up to 60 wt% due to the bimolecular substitution mechanism. The hydrolysis gives an acidic environment favorable for cellulose decomposition, SCG particle size reduction and lipid conversion. The optimal fatty acid ethyl ester yield was 11.8 wt% based on the mass of dried SCG with 3.36 ml ethanol and 3.16 ml DCE at 196.8 °C through the response surface methodology. Using the solvo-thermal effect, direct utilization of wet SCG as a biodiesel feedstock provides not only economic feasibility without using drying process and additional acid catalyst but also environmental advantage of recycling the municipal waste.

Co-liquefaction of spent coffee grounds and lignocellulosic feedstocks.

Co-liquefaction of spent coffee grounds (SCG) with paper filter (PF), corn stalk (CS) and white pine bark (WPB) respectively, was examined in subcritical water for bio-crude oil production. The optimum reaction temperature was 250°C, and the mixing biomass ratio was 1:1. SCG and CS was identified to be the best feedstock combination with a significant positive synergetic effect in the co-liquefaction process with 5% NaOH as a catalyst. The yield of bio-crude oil was increased by 20.9% compared to the mass averaged yield from two feedstocks, and the oil quality was also improved in terms of viscosity and relative molecular mass. A negative effect presented in the co-liquefaction of SCG/WPB. The resulting bio-crude oils were characterized by elemental analyzer, GC-MS, GPC and viscometer, indicating that mixing feedstock in the co-liquefaction process also influenced the higher heating value (HHV), viscosity, molecular mass and chemical composition of bio-crude oil.

In-situ transesterification of wet spent coffee grounds for sustainable biodiesel production.

This work addresses in-situ transesterification of wet spent coffee grounds (SCGs) for the production of biodiesel. For in-situ transesterification process, the methanol, organic solvent and acid catalyst were mixed with wet SCG in one pot and the mixture was heated for simultaneous lipid extraction and transesterification. Maximum yield of fatty acid methyl esters (FAME) was 16.75wt.% based on the weight of dry SCG at 95°C. Comprehensive experiments were conducted with varying temperatures and various amounts of moisture, methanol, co-solvent and acid catalyst. Moderate polar and alcohol-miscible organic solvent is suitable for the high FAME yield. Unsaturated FAMEs are subject to oxidative cleavage by nitric acid and shorter chain (C6 and C10) FAMEs were mainly produced while sulfuric acid yielded long chain unsaturated FAMEs (C16 and C18). Utilization of wet SCGs as a biodiesel feedstock gives economic and environmental benefits by recycling the municipal waste.

Carbon dioxide assisted sustainability enhancement of pyrolysis of waste biomass: A case study with spent coffee ground.

This work mainly presents the influence of CO2 as a reaction medium in the thermo-chemical process (pyrolysis) of waste biomass. Our experimental work mechanistically validated two key roles of CO2 in pyrolysis of biomass. For example, CO2 expedited the thermal cracking of volatile organic compounds (VOCs) evolved from the thermal degradation of spent coffee ground (SCG) and reacted with VOCs. This enhanced thermal cracking behavior and reaction triggered by CO2 directly led to the enhanced generation of CO (∼ 3000%) in the presence of CO2. As a result, this identified influence of CO2 also directly led to the substantial decrease (∼ 40-60%) of the condensable hydrocarbons (tar). Finally, the morphologic change of biochar was distinctive in the presence of CO2. Therefore, a series of the adsorption experiments with dye were conducted to preliminary explore the physico-chemical properties of biochar induced by CO2.

Production of polyhydroxyalkanoates from spent coffee grounds oil obtained by supercritical fluid extraction technology.

Spent coffee grounds (SCG) oil was obtained by supercritical carbon dioxide (scCO2) extraction in a pilot plant apparatus, with an oil extraction yield of 90% at a 35kgkg(-1) CO2/SCG ratio. Cupriavidus necator DSM 428 was cultivated in 2L bioreactor using extracted SCG oil as sole carbon source for production of polyhydroxyalkanoates. The culture reached a cell dry weight of 16.7gL(-1) with a polymer content of 78.4% (w/w). The volumetric polymer productivity and oil yield were 4.7gL(-1)day(-1) and 0.77gg(-1), respectively. The polymer produced was a homopolymer of 3-hydroxybutyrate with an average molecular weight of 2.34×10(5) and a polydispersity index of 1.2. The polymer exhibited brittle behaviour, with very low elongation at break (1.3%), tensile strength at break of 16MPa and Young's Modulus of 1.0GPa. Results show that SCG can be a bioresource for polyhydroxyalkanoates production with interesting properties.

Surgery for psychiatric disorders.

Surgery in psychiatric disorders has a long history and has regained momentum in the past few decades with deep brain stimulation (DBS). DBS is an adjustable and reversible neurosurgical intervention using implanted electrodes to deliver controlled electrical pulses to targeted areas of the brain. It holds great promise for therapy-refractory obsessive-compulsive disorder. Several double-blind controlled and open trials have been conducted and the response rate is estimated around 54%. Open trials have shown encouraging results with DBS for therapy-refractory depression and case reports have shown potential effects of DBS on addiction. Another promising indication is Tourette syndrome, where potential efficacy of DBS is shown by several case series and a few controlled trials. Further research should focus on optimizing DBS with respect to target location and increasing the number of controlled double-blinded trials. In addition, new indications for DBS and new target options should be explored in preclinical research.

Gene Expression Profiling of SH-SY5Y Human Neuroblastoma Cells Treated with Ginsenoside Rg1 and Rb1

OBJECTIVES: The ginsenoside Rg1 and Rb1, the major components of ginseng saponin, have neurotrophic and neuroprotective effects including promotion of neuronal survival and proliferation, facilitation of learning and memory, and protection from ischemic injury and apoptosis. In this study, to investigate the molecular basis of the effects of ginsenoside on neuron, we analyzed gene expression profiling of SH-SY5Y human neuroblastoma cells treated with ginsenoside Rg1 or Rb1. METHODS: SH-SY5Y cells were cultured and treated in triplicate with ginsenoside Rg1 or Rb1(80micrometer, 40micrometer, 20micrometer). The proliferation rates of SH-SY5Y cells were determined by MTT assay and microscopic examination. We used a high density cDNA microarray chip that contained 8K human genes to analyze the gene expression profiles in SH-SY5Y cells. We analyzed using the Significance Analysis of Microarray(SAM) method for identifying genes on a microarray with statistically significant changes in expression. RESULTS: Treatment of SH-SY5Y cells with 80microliter ginsenoside Rg1 or Rb1 for 36h showed maximal proliferation compared with other concentrations or control. The results of the microarray experiment yielded 96 genes were upregulated(> or =3 fold) in Rg1 treated cells and 40 genes were up-regulated(> or =2 fold) in Rb1 treated cells. Treatment with ginsenoside Rg1 for 36h induced the expression of some genes associated with protein biosynthesis, regulation of transcription or translation, cell proliferation and growth, neurogenesis and differentiation, regulation of cell cycle, energy transport and others. Genes associated with neurogenesis and neuronal differentiation such as SCG10 and MLP increased in ginsenoside Rg1 treated cells, but such changes did not occur in Rb1- group. CONCLUSION: Our data provide novel insights into the gene mechanisms involved in possible role for ginsenoside Rg1 or Rb1 in mediating neuronal proliferation or cell viability, which can elicit distinct patterns of gene expression in neuronal cell line. Ginsenoside Rg1 have more broad and strong effects than ginsenoside Rb1 in gene expression and related cellular physiology. In addition, we suggest that SCG10 gene, which is known to be expressed in neuronal differentiation during development and neuronal regeneration during adulthood, may have a role in enhancement of activity dependent synaptic plasticity or cytoskeletal regulation following treatment of ginsenoside Rg1. Further, ginsenoside Rg1 may have a possible role in regeneration of injured neuron, promotion of memory, and prevention from aging or neuronal degeneration.