Assessment of the Impact of Pretreatment of Spent Coffee Grounds with Diluted Sulfuric Acid on the Efficiency of Methane and Lactic Acid Fermentation

ABSTRACTEmpty fruit bunches (EFB), coffee grounds (CG), and palm oil mill sludge (POMS) were composted in the laboratory for 60 days in order to study the composting process of lignocellulosic food industry wastes. In the first part of the experiment, EFB, CG, and POMS were composted alone (composting of single lignocellulosic material), and in the second part, EFB was composted with CG (1EFB:1CG ratio) and POMS (1EFB:1POMS ratio). The effects of different turning frequencies on the physical and chemical properties of composting were observed and its relation with the degradation process was highlighted. Results showed that oil and grease were first degraded, followed by recalcitrant compounds like alpha-cellulose, hemicellulose, and lignin. Cellulose and hemicellulose were degraded mainly during the 60 days of composting, and the progressive reduction of the cellulose/lignin ratio proved that the main evolution of these wastes took place. It was observed that 3, 6, and 9 days of turning frequency did not affect the physicochemical properties of the compost. Composting EFB alone failed to achieve the required quality of maturity compost within 60 days, while CG and POMS recorded low in biological activity. Better results were shown in composting of EFB mixed with coffee grounds and POMS, the C/N ratio dropped to less than 20 by the 8th week of the composting period. Composting of mixed lignocellulosic materials showed larger changes compared to composting of single lignocellulosic material, reaching a C/N ratio below 20 within 8 weeks.

Coffee is one of the most popular drinks, linked directly to tradition and culture. Coffee consumption continues to increase, resulting in very large quantities solid residue in the form of spent coffee grounds. Spent coffee grounds (SCG) contain a large amount of organic compounds. This paper aims to review a number of options to utilize productively SCG in electronics applications that currently being researched. Several previous research and innovations explored certain components as value-added products. However, by-products of coffee can also be considered as a potential functional material to be utilized in various electronic applications. Utilization of coffee grounds is an urgent need through a number of innovative and practical ideas to increase the added value and potential of coffee grounds as a whole.

Glycerol conversion into value-added products in presence of a green recyclable catalyst: Acid black carbon obtained from coffee ground wastes

Time and storage space are the main constraints facing by the current Malaysia composting industries which are handling lignocellulosic food industry waste such as empty fruit bunch (EFB), coffee ground (CG) and palm oil mill sludge (POMS). To develop an efficient accelerated composting method for lignocellulosic food industry waste in Malaysia, a new approach which combined two distinct technologies to achieve rapid composting; (i) co-composting with combination of different lignocellulosic materials and (ii) inoculation of the co-composting with mixture of microorganism were presented in this study. All the mixtures achieved thermophilic condition on the first week of composting, with 50% EFB + 50% CG combination recorded the highest temperature of 56 °C. The mixtures with initial C/N ratios within 25–35 showed the highest reduction in holocellulose, cellulose, hemicellulose and lignin content while compost mixture with initial C/N ratio more than 50 had a minimal reduction. The C/N ratio for 50% EFB + 25% CG + 25% POMS combination was reduced to less than 20 after 4 weeks of co-composting process while the other treatments needed longer composting duration. During thermophilic phase, higher population of bacteria (107–108 CFU/g DW) was observed, followed by fungi (105–106 CFU/g DW) and actinomycetes (105–106 CFU/g DW) populations. However, higher population of actinobacteria (104–106 CFU/g DW) compared to bacterial (104–105 CFU/g DW) and fungal (103–104 CFU/g DW) was found during latter stages. By reducing both the time and space required for composting lignocellulosic food industry waste, this accelerated co-composting method may be a viable option for food industries searching for a long-term, practical solution for solid biowaste disposal issues.

Every year, large amounts of food leftovers are thrown away in catering establishments and households. Industry and agriculture produce lignocellulosic residues, including paper dust and willow biomass, which cause environmental problems if not properly disposed of. The aim of this study is to investigate the biogas and biomethane yields of these biomasses during anaerobic co-fermentation under mesophilic conditions. Biogas yields were determined by co-fermentation of food (hospital canteen, cafeteria, and household) residues and lignocellulosic (paper dust and shredded willow) biomass in a number of 0.72 L bioreactors. All bioreactors were divided into groups having the same content in reactors within each group to ensure the reliability of the results. Groups of bioreactors used for anaerobic fermentation were inoculums (0.5 L) only, inoculums with individual biomass, and inoculums with mixture of two or more biomass. Bioreactors were placed in three different thermostats with 16 bioreactors in each thermostat. Single fill batch anaerobic fermentation (AF) process was provided at 28, 33 and 38 °C. Individual reactor groups were equipped with graphite electrodes connected to DC voltage of 0.7 V. The biogas released in the bioreactor was collected into a gas bag outside the reactor. AF was maintained until gas emission ceased. The highest biogas yield in the AF process was obtained from the bioreactors at a temperature of 38 °C and the lowest at a temperature of 28 °C. Co-fermentation of biomass increased biogas and methane yields compared to AF treatment of individual biomasses. Exposure to the electric field decreased the methane yield. The energy balance on the AF process with the application of the electric field should be calculated by considering also the energy of hydrogen released from substrates with electrodes installed.

Valorisation of solid biowastes: The lactic acid alternative

This study aims to analyse the financial feasibility of the ground coffee production business undertaken by coffee farmers and processors by applying local innovations at the cultivation, post-harvest handling, and coffee processing stages in the coffee production centre of Garut Regency. This study used a quantitative approach to provide a comprehensive understanding of the feasibility of the ground coffee business with local innovations applied by coffee farmers and processors in Garut Regency. Local innovations in coffee production include pruning techniques, grafting, solar dryer dome technology for herbal coffee making, the use of local roasting machines, and the utilization of coffee waste into value-added products such as ceramics, organic fertilizer, and dodol. Quantitative analysis of coffee processing business feasibility based on NPV value of Rp 38,394,163, Gross B/C 1.08, Net B/C 1.25, IRR 17.73 percent, payback period 7.7. These results showed that the business carried out by ground coffee processors in the production centre area is feasible. These results of the sensitivity analysis show that an increase in the price of coffee fruit raw materials at a limit of 16.67 percent and a decrease in ground coffee production at a limit of 11.37percent still produces a positive value and the business is still feasible. These results of the switching value analysis explain that the tolerance limit for the increase in the price of coffee fruit raw materials can be tolerated if the rise is no more than 26.66 percent and the decrease in ground coffee production does not exceed 7.023percent if it exceeds within 1 year then the business is not feasible.

Biorefinery, which utilizes carbon-neutral biomass as a resource, is attracting attention as a significant alternative in a modern society confronted with climate change. In this study, spent coffee grounds (SCGs) were used as the feedstock for lactic acid fermentation. In order to improve sugar conversion, alkali pretreatment was optimized by a statistical method, namely response surface methodology (RSM). The optimum conditions for the alkali pretreatment of SCGs were determined as follows: 75 °C, 3% potassium hydroxide (KOH) and a time of 2.8 h. The optimum conditions for enzymatic hydrolysis of pretreated SCGs were determined as follows: enzyme complex loading of 30-unit cellulase, 15-unit cellobiase and 50-unit mannanase per g biomass and a reaction time of 96 h. SCG hydrolysates were used as the carbon source for Lactobacillus cultivation, and the conversions of lactic acid by L. brevis ATCC 8287 and L. parabuchneri ATCC 49374 were 40.1% and 55.8%, respectively. Finally, the maximum lactic acid production by L. parabuchneri ATCC 49374 was estimated to be 101.2 g based on 1000 g of SCGs through the optimization of alkali pretreatment and enzymatic hydrolysis.

Starch based lactic acid fermentation technology was examined and optimized using a non-amylolitic, mesophilic lactic acid bacterium. Comparing simultaneous saccharification and fermentation (SSF) and separate hydrolysis and fermentation (SHF) technologies several issues arose and applying the two techniques needed several compromises concerning the overall process time. A combined hydrolysis and fermentation method was developed which incorporate the advantages of SSF and SHF technologies: applying a time delay in inoculation and cutting down hydrolysis time before fermentation, an optimal inoculation and high efficiency was achieved by kinetic model aided experimental work. Experimental verification of the model gave an excellent productivity result: 4.32 g L^-1h^-1 calculated with only the fermentation time, and 2.88 g L^-1h^-1 calculated with the overall time of the two processes. With this method, hydrolysis and fermentation time was successfully reduced, enhancing lactic acid productivity and depressing production cost of this low-value chemical.

Added-value molecules recovery and biofuels production from spent coffee grounds

The conventional approach in the production of biofuels from biomass requires lipid extraction prior to hydrolysis for sugar recovery. This study investigated a new approach in the valorization of spent coffee grounds (SCG) by employing direct hydrolysis of non-delipidated SCG expecting to recover the available lipids in the solid residue present in higher concentrations. Sugar content (43–49%) as determined with the proposed approach and expressed in extractive-free basis, were comparable to that of conventional approaches employing lipid extraction prior to hydrolysis (41–51%). Experiments employing dilute acid hydrolysis were carried out under various sulfuric acid concentrations (1–5% v/v H2SO4) and hydrolysis times (30–180 min). A maximum sugar yield of 29% (~62% recovery) was obtained at a solvent-to-solid ratio of 8 mL/g with 5% v/v acid and a hydrolysis time of 3 h. Hydrolysates obtained contain 33.4 g/L of sugar, 0.056 g/L 5-HMF and 0.012 g/L furfural. Also, it was found that lipids remained intact even after hydrolysis and were successfully recovered with lipid recoveries of 99–103%. Solid residues after hydrolysis were ~68% of the initial biomass having a moisture content of ~65%, thus reducing the total amount of moisture to be removed and energy required in the drying step prior to lipid extraction.

In recent years, developing sustainable management by transforming organic biomass wastes into value-added products has become advantageous. Cauliflower (CF) and grapes are cultivated in hilly regions of India at all times, which facilitates the recycling of those waste into biogas generation for substantial energy share. This techno-assessment approach examines biogas yield via anaerobic co-digestion of feedstocks include CF, grape residue (GR) as substrates, dairy manure (DM) as inoculum and water (W) considering mass proportions of (GR:CF:DM:W) in case1: 50/10/10/30, case2: 10/50/10/30, case3: 15/45/10/30, case4: 30/30/10/30, and case5: 40/20/10/30. Real-time experimentation studies are carried out for 45 days in a 50 liter laboratory-type biogas digester under mesophilic conditions. The anaerobic digestion of each batch utilizing the selected feedstocks with 10.496, 10.935, 10.879, 10.713, and 10.602 kg of total volatile solids produces biogas yields of 0.584, 0.638, 0.704, 0.766, and 0.785 m3/kg VS. Furthermore, methane yields of 0.403, 0.451, 0.502, 0.559, and 0.580 m3/kg VS are attained. According to the results, anaerobic co-digestion of feedstocks in case5 promotes maximum biogas and methane yields, paving the path for greater value added transition from bio-mass waste to bio-gas as an alternate source of clean energy especially in hilly regions which has become more beneficial for improved energy conservation and management with eco-friendliness.

Symptosite, logiciel de suivi clinique en ligne pour professionnels de santé

Electropolar effects on anaerobic fermentation of lignocellulosic materials in novel single-electrode cells

Indonesia has great potential in producing large quantities of renewable energy sources, such as biomass. Biogas is a renewable energy source produced from biomass. It is can be developed in agricultural countries producing rice and coffee, where a large amount of waste is produced in the form of rice husks and coffee grounds. This study examined the effect of physiochemical pretreatment and the C/N ratio on biogas production using coffee grounds and rice husk mixtures. Physical pretreatment was conducted by grinding the mixture up to 50 mesh size, followed by chemical pretreatment by soaking the mixture in 3% KOH; moreover, the variation in the C/N ratio was set at 25 and 30. Anaerobic bacteria were acquired from rumen fluid. The ratio of the coffee ground material, rice husks, and rumen fluid was 1:1:1. This research was conducted in duplicate under batch conditions at ambient temperature (25–35 oC) with a digester volume of 1.5 L. Biogas productivity was measured every 2 d for 60 d. The experimental results indicated that biogas production with a C/N ratio of 30 was 13.3–66.5% higher than that with a C/N ratio of 25. The inclusion of physical pretreatment at a C/N ratio of 30 increased biogas production by up to 31.3%. Moreover, the inclusion of a chemical pretreatment at a C/N ratio of 30 resulted in 30.3% higher biogas production. The kinetics model of biogas production showed that a C/N ratio of 30 with physical and alkaline pretreatment can produce maximum biogas yields of 6,619 mL and 6,570 mL, respectively. Overall, both pretreatments sequentially increased the biogas production significantly.