Conversion Of Waste Biomass Research Articles

Cellulosome Localization Patterns Vary across Life Stages of Anaerobic Fungi.

ABSTRACTAnaerobic fungi (Neocallimastigomycota) isolated from the guts of herbivores are powerful biomass-degrading organisms that enhance their degradative ability through the formation of cellulosomes, multienzyme complexes that synergistically colocalize enzymes to extract sugars from recalcitrant plant matter. However, a functional understanding of how fungal cellulosomes are deployed in vivo to orchestrate plant matter degradation is lacking, as is knowledge of how cellulosome production and function vary throughout the morphologically diverse life cycle of anaerobic fungi. In this work, we generated antibodies against three major fungal cellulosome protein domains, a dockerin, scaffoldin, and glycoside hydrolase (GH) 48 protein, and used them in conjunction with helium ion and immunofluorescence microscopy to characterize cellulosome localization patterns throughout the life cycle of Piromyces finnis when grown on simple sugars and complex cellulosic carbon sources. Our analyses reveal that fungal cellulosomes are cell-localized entities specifically targeted to the rhizoids of mature fungal cells and bodies of zoospores. Examination of cellulosome localization patterns across life stages also revealed that cellulosome production is independent of growth substrate in zoospores but repressed by simple sugars in mature cells. This suggests that further exploration of gene regulation patterns in zoospores is needed and can inform potential strategies for derepressing cellulosome expression and boosting hydrolytic enzyme yields from fungal cultures. Collectively, these findings underscore how life cycle-dependent cell morphology and regulation of cellulosome production impact biomass degradation by anaerobic fungi, insights that will benefit ongoing efforts to develop these organisms and their cellulosomes into platforms for converting waste biomass into valuable bioproducts.

Transport Cost for Carbon Removal Projects With Biomass and CO2 Storage

Strategies to remove carbon from the atmosphere are needed to meet global climate goals. Promising strategies include the conversion of waste biomass to hydrogen, methane, liquid fuels, or electricity coupled with CO2 capture and storage (CCS). A key challenge for these projects is the need to connect geographically dispersed biomass supplies with geologic storage sites by either transporting biomass or CO2. We assess the cost of transport for biomass conversion projects with CCS using publicly available cost data for trucking, rail, and CO2 pipelines in the United States. We find that for large projects (order of 1 Mt/yr CO2 or greater), CO2 by pipeline is the lowest cost option. However, for projects that send most of the biomass carbon to storage, such as gasification to hydrogen or electricity production, biomass by rail is a competitive option. For smaller projects and lower fractions of carbon sent to storage, such as for pyrolysis to liquid fuels, CO2 by rail is the lowest cost option. Assessing three plausible example projects in the United States, we estimate that total transport costs range from $24/t-CO2 stored for a gasification to hydrogen project traversing 670 km to $36/t for a gasification to renewable natural gas project traversing 530 km. In general, if developers have flexibility in choosing transport mode and project type, biomass sources and storage sites can be connected across hundreds of kilometers for transport costs in the range of $20-40/t-CO2 stored. Truck and rail are often viable modes when pipelines cannot be constructed. Distances of 1,000 km or more can be connected in the same cost range when shared CO2 pipelines are employed.

Efficient honeycomb–shaped biochar anodes for lithium-ion batteries from Eichhornia crassipes biomass

Converting waste biomass into biochar is a means for solving both environmental pollution and energy shortage. Here we transformed Eichhornia crassipes, a harmful floating plant, into a honeycomb-shaped and heteroatoms-rich biochar by KOH activation during carbonization, and we tested this biochar as anode for lithium-ion batteries. Results show that the biochar has a high surface area of 278.56 m2·g−1, a honeycomb-like porous structure, and is rich in heteroatoms, e.g., 3.42% N, 20.82% O, and 0.83% S. Biochar anodes displayed a higher initial reversible specific capacity of 697 mAh·g−1 at 50 mA·g−1, a higher rate capability of 229.7 mAh·g−1 at 3000 mA·g−1, and a better cyclic stability than commercial graphite. The enhanced electrochemical performance could be attributed to the interconnected porous structure that promotes Li+ transfer and electrolyte infiltration, and to the presence of heteroatoms. This approach can be easily industrialized as a substitute of graphite.

Biomass waste-to-energy supply chain optimization with mobile production modules

Biomass waste is a naturally occurring agricultural byproduct. It is estimated that about 60 million tons per year can be extracted sustainably without altering land use patterns or competing with existing demands. Utilizing this waste is logistically challenging due to the inherent low density and distributed availability of biomass. This work proposes a supply chain optimization problem which decides where to locate and relocate mobile and modular production units to convert biomass waste to energy. Both deterministic and two-stage stochastic formulations are presented, accounting for the inherent uncertainty of where and how much biomass is produced. The framework is applied to case studies analyzing the states of Minnesota and North Carolina. Results from both states show that mobile production modules lead to supply chain cost savings of 1–4%, or millions of dollars per year. Additionally, this work demonstrates the benefit of mobile modules as a means of protecting against uncertainty.

Research on High-Value Utilization of Carbon Derived from Tobacco Waste in Supercapacitors.

Large quantities of tobacco stalks residues are generated and discarded as crop waste or combusted directly every year. Thus, we need to find an appropriate way to dispose of this type of waste and recycle it. The conversion of biomass waste into electrode materials for supercapacitors is entirely in line with the concept of sustainability and green. In this paper, tobacco-stalk-based, porous activated carbon (TC) was successfully synthesized by high-temperature and high-pressure hydrothermal pre-carbonization and KOH activation. The synthesized TC had a high pore volume and a large surface area of 1875.5 m2 g−1, in which there were many mesopores and interconnected micro-/macropores. The electrochemical test demonstrated that TC-1 could reach a high specific capacitance of up to 356.4 F g−1 at a current density of 0.5 A g−1, which was carried in 6M KOH. Additionally, a symmetrical supercapacitor device was fabricated by using TC-1 as the electrode, which delivered a high energy density up to 10.4 Wh kg−1 at a power density of 300 W kg−1, and excellent long-term cycling stability (92.8% of the initial capacitance retention rate after 5000 cycles). Therefore, TC-1 is considered to be a promising candidate for high-performance supercapacitor electrode materials and is a good choice for converting tobacco biomass waste into a resource.

The Utilisation of Palm Oil and Oil Palm Residues and the Related Challenges as a Sustainable Alternative in Biofuel, Bioenergy, and Transportation Sector: A Review

The importance of energy demands that have increased exponentially over the past century has led to the sourcing of other ideal power solutions as the potential replacement alternative to the conventional fossil fuel. However, the utilisation of fossil fuel has created severe environmental issues. The identification of other renewable sources is beneficial to replace the energy utilisation globally. Biomass is a highly favourable sustainable alternative to renewable resources that can produce cleaner, cheaper, and readily available energy sources in the future. The palm oil industry is essentially ideal for the availability of abundant biomass resources, where the multifaceted residues are vital for energy production through the conversion of biomass waste into value-added products simultaneously. This article discusses the utilisation of palm oil and its residues in the energy and transportation sector. Assessment and evaluation on the feasibility of palm oil and its residues were made on the current valorisation methods such as thermochemical and biochemical techniques. Their potential as transportation fuels were concurrently reviewed. This is followed by a discussion on future challenges of palm oil industries that will take place globally, including the prospects from government and nongovernment organisations for the development of palm oil as a sustainable alternative replacement to fossil fuel. Hence, this review aims to provide further insight into the possibilities of palm oil and its residues towards sustainable development with reduced environmental-related issues.

Conversion of Babool wood residue to 5-Hydroxymethyl Furfural: Kinetics and Process modelling

This study proposes an integrated approach for the formation of total reducing sugars (TRS) and 5-hydroxymethyl furfural (5-HMF) from forestry biomass. Detailed kinetics was studied using an irreversible series model and the developed kinetic model is congruent with the experimental data. The obtained rate constants were also applied to gain insight for designing continuous reactor configurations. Maximum TRS (32.28%) and 5-HMF yield (42.32%) was obtained in 67.13 min and 311.62 min at 120 °C using single-stage CSTR whereas complete conversion of TRS was observed in 17.03 min with significant 5-HMF yield (23.68%) in 39.07 min at 120 °C using two equal-sized CSTR in series. Also, maximum TRS yield (30.61%) and 5-HMF yield (58.41%) was observed in 67.13 min and 193.38 min respectively using single-stage PFR. The proposed model for Babool wood hydrolysis will be valuable to facilitate the cost-effective and sustainable conversion of waste biomass to bio-based fuels.

Hydrothermal Carbonization of Lemon Peel Waste: Preliminary Results on the Effects of Temperature during Process Water Recirculation

Hydrothermal carbonization (HTC) is a promising thermochemical pre-treatment to convert waste biomass into solid biofuels. However, the process yields large amounts of organic process water (PW), which must be properly disposed of or reused. In this study, the PW produced from the hydrothermal carbonization of lemon peel waste (LP) was recycled into HTC process of LP with the aim of maximize energy recovery from the aqueous phase while saving water resources and mitigating the overall environmental impact of the process. The effects of HTC temperature on the properties of solid and liquid products were investigated during PW recirculation. Experiments were carried out at three different operating temperatures (180, 220, 250 °C), fixed residence times of 60 min, and solid to liquid load of 20 wt%, on a dry basis. Hydrochars were characterized in terms of proximate analysis and higher heating values while liquid phases were analyzed in terms of pH and total organic carbon content (TOC). PW recirculation led to a solid mass yield increase and the effect was more pronounced at lower HTC temperature. The increase of solid mass yield, after recirculation steps (maximum increase of about 6% at 180 °C), also led to a significant energy yield enhancement. Results showed that PW recirculation is a viable strategy for a reduction of water consumption and further carbon recovery; moreover preliminary results encourage for an in-depth analysis of the effects of the PW recirculation for different biomasses and at various operating conditions.

Electrochemical biomass upgrading: degradation of glucose to lactic acid on a copper(ii) electrode.

Biomass upgrading – the conversion of biomass waste into value-added products – provides a possible solution to reduce global dependency on nonrenewable resources. This study investigates the possibility of green biomass upgrading for lactic acid production by electrochemically-driven degradation of glucose. Herein we report an electrooxidized copper(ii) electrode which exhibits a turnover frequency of 5.04 s−1 for glucose conversion. Chronoamperometry experiments under varied potentials, alkalinity, and electrode preparation achieved a maximum lactic acid yield of 23.3 ± 1.2% and selectivity of 31.1 ± 1.9% (1.46 V vs. RHE, 1.0 M NaOH) for a room temperature and open-to-atmosphere reaction. Comparison between reaction conditions revealed lactic acid yield depends on alkalinity and applied potential, while pre-oxidation of the copper had a negligible effect on yield. Post-reaction cyclic voltammetry studies indicated no loss in reactivity for copper(ii) electrodes after a 30 hour reaction. Finally, a mechanism dependent on solvated Cu2+ species is proposed as evidenced by similar product distributions in electrocatalytic and thermocatalytic systems.

MCM-41 modified heterogeneous catalysts from rice husk for selective oxidation of styrene into benzaldehyde

This study examined the preparation of MCM-41, Ni-MCM-41 and Co-MCM-41 from silica extracted from rice husk ash (RHA) via sol–gel technique. The materials were characterized by X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FT-IR), Diffuse reflectance UV–Vis (DR/UV–Vis),Energy Dispersive X-ray Spectrometry (EDX), N 2 adsorption–desorption and NH 3 TPD. XRD and TEM analyses showed reduction in the long range order upon the introduction of heteroatoms into MCM-41 framework. Successful substitution of Si 4 + with metal cations was verified by the shifting in the siloxane (Si-O-Si) bond. Presence of nickel phyllosilicates was evidenced from the FT-IR and DR/UV–Vis investigations. Mesoporous behavior with capillary condensation was unchanged even after the incorporation of Ni and Co species into the MCM-41 matrix. MCM-41 and modified MCM-41 catalysts were evaluated in the liquid-phase oxidation of styrene for 4 h under the influence of reaction parameters such as reaction temperature, catalyst loading, types of solvent and molar ratio of styrene : H 2 O 2 . Under the optimum condition of 343 K, 0.20 g catalyst, 1:4 molar ratios and DMF as the reaction medium, the activity was found to increase following the trend: Ni-MCM-41 (79.9%) >Co-MCM-41(56.6%) > MCM-41 (40.7%). Benzaldehyde was the sole product over Ni-MCM-41 and Co-MCM-41 while MCM-41 gave benzaldehyde (96.0%) and styrene oxide (4.0%). Surface characteristics and TPD acidity strength was found to govern the catalysis. Negligible leaching (0.448 ppm) and exceptional activity during successive reruns demonstrates that Ni-MCM-41 was beyond doubt, heterogeneous in nature. This research signifies a successful conversion of waste biomass into value added products. • Cobalt and nickel supported MCM-41 catalysts were synthesized from rice husk. • The catalyst was active in the oxidation of styrene at mild condition. • Benzaldehyde was the sole product over the modified MCM-41 catalysts. • The catalysis of Ni-MCM-41 was heterogeneous in nature with minor leaching. • Successful conversion of waste biomass into benign product.

Evolution of cellulose acetate to monolayer graphene

Converting biomass waste into high-value products presents a challenging task in the environmental field. Growth of graphene from solid-state precursors is cost-effective and is becoming a hot research topic. However, the underlying mechanisms are as yet unclear. In this work, we report a novel method for directly growing adlayer-free large area graphene from cellulose acetate, the main component of cigarette filter waste. The evolution of cellulose acetate to reduced graphene oxide and finally to graphene is shown in this work for the first time. The effect of various growth parameters, hydrogen concentration and Cu grain boundaries on the size and qualities of the monolayer graphene domains is clarified. Finally, the mechanism for the growth of graphene from a solid-state precursor is proposed. The field-effect-transistor fabricated from transferred monolayer graphene demonstrated high electron and hole mobilities ∼1500 cm2/(V·s). This work presents a new opportunity for converting biomass waste into high-value graphene products.

Conversion of Biomass Wastes into Activated Carbons by Chemical Activation for Hydrogen Storage

AbstractThe investigation of activated carbons for hydrogen storage has attracted great attention due to their easy availability, adjustable microstructure and large specific surface area. Herein, three kinds of agricultural biomass wastes (bagasse, cornstalk and pine powder) are used to prepare activated carbons via chemical activation (H3PO4, ZnCl2 and KOH). The interinfluence of precursors and activators on the activated carbon was investigated. We found that the same biomass treated with different activators possessing totally unique characters, whereas three kinds of biomass activated with the same activators exhibited mild difference. Specifically, KOH contributed the largest specific surface area. The optimized activated carbons were used for hydrogen storage measurement and exhibited high storage capacity. Hydrogen storage capacity of activated carbon is proportional to volume of micropores. Conversion of cheap biomass wastes into activated carbon for hydrogen storage is significant for rational utilization of resources and energy storage.

Effects of temperature and solvent on hydrothermal liquefaction of the corncob for production of phenolic monomers

The hydrothermal liquefaction (HTL) process is a promising direction for the conversion of waste biomass into valuable chemicals/fuels. Optimization of the process parameters for HTL of biomass has been the research scope in recent years. The study aims to examine the effects of process variables such as the effect of temperature, the role of solvents: water (H2O), methanol (CH3OH), and ethanol (C2H5OH) on hydrothermal liquefaction of the corncob biomass. Hydrothermal liquefaction has been carried out at temperatures of 260, 280, and 300 °C with a reaction holding time of 15 min. The maximum bio-oil yield was obtained (38.0 wt%) at 280 °C in the presence of H2O, whereas in the case of CH3OH and C2H5OH solvents, the maximum bio-oil yield was 18.67 wt.% and 16.83 wt.% at 260 °C and 300 °C, respectively. The solvent efficiency in corncob liquefaction was observed as H2O ˃ CH3OH ˃ C2H5OH for bio-oil production. The obtained bio-oils were characterized in detail using GC-MS, FT-IR, and 1H NMR. From the GC-MS analysis of bio-oil, the phenolic compounds were observed to a higher degree (60%) in the case of H2O solvent than CH3OH and C2H5OH solvent (57% and 46%). Also, FT-IR analysis showed that higher aromatic functional groups present in bio-oil obtained with water solvent while liquefaction with alcoholic solvent showed higher ester functional groups. Moreover, the analysis of bio-residues indicated that the decomposition of the corncob occurred in a different way during HTL with the presence of different solvents.

Directional valorization of eucalyptus waste into value-added chemicals by a novel two-staged controllable pyrolysis process

Fast pyrolysis is a promising way to convert biomass waste into value-added chemicals, but current approaches give poor yield and selectivity for the desired chemicals (e.g. anhydrosugars). This study reported a novel two-staged controllable pyrolysis process consisting of torrefaction of H2SO4-impregnated eucalyptus waste and subsequent fast pyrolysis for achieving directional valorization of eucalyptus waste. Under different torrefaction temperature and holding time, the performance of two-staged controllable pyrolysis of 0.5%H2SO4-impregnated eucalyptus waste was evaluated. The highest total yield of levoglucosan (82.4%, based on cellulose) was obtained by torrefaction at 300 °C with a holding time of 240 s followed by fast pyrolysis at 550 °C, while the highest total yield of xylosan (17.0%, based on hemicellulose) was obtained from torrefaction at 280 °C with a holding time of 20 s combined with subsequent fast pyrolysis at 550 °C. It is demonstrated that H2SO4 impregnation can achieve the directional valorization of holocellulose into anhydrosugars during torrefaction at low temperature, while evidently inhibiting the degradation of lignin and the formation of non-condensable gas and C1-C4 light oxygenates. The unreacted holocellulose and lignin in torrefied eucalyptus waste can be further converted into anhydrosugars and phenols via subsequent fast pyrolysis. This study provides a very simple and efficient strategy to achieve staged and directional valorization of holocellulose and lignin in biomass waste into value-added chemicals.

Lignocellulolytic Enzymes in Biotechnological and Industrial Processes: A Review

Tons of anthropological activities contribute daily to the massive amount of lignocellulosic wastes produced annually. Unfortunately, their full potential usually is underutilized, and most of the biomass ends up in landfills. Lignocellulolytic enzymes are vital and central to developing an economical, environmentally friendly, and sustainable biological method for pre-treatment and degradation of lignocellulosic biomass which can lead to the release of essential end products such as enzymes, organic acids, chemicals, feed, and biofuel. Sustainable degradation of lignocellulosic biomass via hydrolysis is achievable by lignocellulolytic enzymes, which can be used in various applications, including but not limited to biofuel production, the textile industry, waste treatment, the food and drink industry, personal care industry, health and pharmaceutical industries. Nevertheless, for this to materialize, feasible steps to overcome the high cost of pre-treatment and lower operational costs such as handling, storage, and transportation of lignocellulose waste need to be deployed. Insight on lignocellulolytic enzymes and how they can be exploited industrially will help develop novel processes that will reduce cost and improve the adoption of biomass, which is more advantageous. This review focuses on lignocellulases, their use in the sustainable conversion of waste biomass to produce valued-end products, and challenges impeding their adoption.

Fruit preservation with bioethanol obtained from the fermentation of brewer’s spent grain with Saccharomyces carlsbergensis

Brewer’s Spent Grain (BSG) is renewable lignocellulosic biomass generated from the beer brewing process. It serves as a substrate for various biotechnological applications. BSG was used as the main substrate for bioethanol production with Saccharomyces carlsbergensis in submerged fermentation. Saccharification and fermentation studies were performed for the production of bioethanol. A sterilized fermenter was loaded with 50 g L-1 of BSG at 29±2 °C and an agitation speed of 180 rpm. pH was adjusted to 6.0 before the addition of 500 mL of yeast culture for 7 days under submerged and optimized conditions. The fermented product was concentrated using a rotary evaporator at 66±1 °C, and ethanol was qualitatively determined by the dichromate method. Bioethanol yield was 22%, with a specific gravity of 0.8 at 28 °C. Fourier-Transform Infrared Spectroscopy (FTIR) confirmed the presence of -CH3 stretch, -OHstretch and -CH2stretch in bioethanol. For the preservative test, Staphylococcus spp., Erwinia spp., Lactobacillus spp., Bacillus spp., Xanthomonas spp., Pseudomonas spp., Micrococcus spp. and Corynebacterium spp. were the bacteria isolated from fruits examined from different regions of Osun State. The genera of fungi isolated were Aspergillus, Colletotrichum, Penicillium, Fusarium, Alternaria, Rhizopus, Candida, Saccharomyces, Geotrichium and Pichia. Bioethanol produced from BSG inhibited the growth of microorganisms with zones of inhibition range from 7.0 mm to 11.5 mm, and thus, selected fruits were preserved. Hence, the fermentation technology of agro-industrial wastes with microorganisms can be adopted to convert waste biomass to useful resources.

Effects of manure-based biochar on uptake of nutrients and water holding capacity of different types of soils

Burning of a huge amount of agricultural waste including crop residues and animal manure is devastating our environment by emitting gases like carbon dioxide (CO2) and methane (CH4). The conversion of waste biomass into biochar could help to mitigate CO2 emissions, reduce the generation of CH4 emissions, and increase the carbon sequestration in the soil for sustainable climate-smart agriculture. In this study, biochar was produced from animal manure through the pyrolysis process at different temperatures, and its effect on the water-holding capacity of different types of soils and maize growth was determined. From a total of 60 ​kg dried cow manure, 20 ​kg biochar with the percentage turnover of 33% was obtained and percent yield of biochar was found to be associated with pyrolytic temperature. The water-holding capacity of sandy loamy soils was found to be increased by 1.5% by mass for each 1% biochar addition in the soil. At a higher percentage of biochar in soil, the water holding capacity was found maximum but the germination percentage was lowest because biochar holds the soil nutrients. In conclusion, manure-based biochar addition could enhance the water holding capacity of the soil and improve crop yield by conserving the rainfall water in arid regions.

Conversion and characterization of Bio-Coke from abundant biomass waste in Malaysia

Depletion of fossil fuels and the adverse impacts burning these fuels has increased the attention towards utilizing biomass energy sources, thus increasing the focus on Bio-Coke technology, which can fully convert biomass waste into alternative fuels. This study analyzed the characteristics of Bio-Coke conversion from biomass abundantly found in Malaysia, which included rice husk, rubber wood sawdust, coconut husk, sugarcane bagasse, oil palm frond, oil palm trunk and empty fruit bunch (EFB). Results indicated better physical feature characteristics of biomass solid fuel. For example, Bio-Coke produced from EFB showed an apparent density of 1.414 g/cm3, combustion duration of 1664 s, and maximum compressive strength at room temperature (25 °C) and 700 °C of 95.107 and 9.412 MPa, respectively, which were found to be higher than that of wood pellet. This study showed Bio-Cokes can be potentially used as an alternative fuel to reduce the usage of coal coke in the future.

Sustainable Solvothermal Conversion of Waste Biomass to Functional Carbon Material: Extending Its Utility as a Biocompatible Cosolvent for Lysozyme

Functional carbon material synthesis from waste biomass by a sustainable method is of prime importance and has wide variety of applications. Herein, functional carbon materials with structural variability are synthesized using a well-known solvothermal method. The leftover pulp waste biomass (PB) of citrus limetta is converted to functional carbon by treatment with a mixture of choline bitartrate (ChBt) and FeCl3 (1:2 mol ratio) as a solvent. The biomass to solvent ratio is varied as 1:1, 0.8:1, and 0.4:1 during solvothermal treatment to obtain PB-1, PB-2, and PB-3 as functional carbon materials, respectively. On characterization, PB carbon materials were found to be rich in oxygen-containing functional groups possessing different morphologies. Furthermore, results suggested the role of solvent as a soft template and catalyst during the synthesis of carbon materials. The feasibility of synthesized carbon materials as a biocompatible cosolvent for lysozyme was evaluated. In the case of PB-2 material (synthesized using 0.8:1 biomass to solvent ratio), results show an enhancement of lysozyme activity by 150%. Besides, spectroscopic and calorimetric data confirm the preservation of thermal and structural stability of lysozyme in the PB-2 solution. Thus, this study stipulates PB-2 as an excellent cosolvent for protein studies. With this work, we aim to delve into an entirely new arena of applications of biomass in the field of biotechnology.

Hydrothermal Carbonization as a Valuable Tool for Energy and Environmental Applications: A Review

Hydrothermal carbonization (HTC) represents an efficient and valuable pre-treatment technology to convert waste biomass into highly dense carbonaceous materials that could be used in a wide range of applications between energy, environment, soil improvement and nutrients recovery fields. HTC converts residual organic materials into a solid high energy dense material (hydrochar) and a liquid residue where the most volatile and oxygenated compounds (mainly furans and organic acids) concentrate during reaction. Pristine hydrochar is mainly used for direct combustion, to generate heat or electricity, but highly porous carbonaceous media for energy storage or for adsorption of pollutants applications can be also obtained through a further activation stage. HTC process can be used to enhance recovery of nutrients as nitrogen and phosphorous in particular and can be used as soil conditioner, to favor plant growth and mitigate desertification of soils. The present review proposes an outlook of the several possible applications of hydrochar produced from any sort of waste biomass sources. For each of the applications proposed, the main operative parameters that mostly affect the hydrochar properties and characteristics are highlighted, in order to match the needs for the specific application.