Bioprocessing of waste biomass for sustainable product development and minimizing environmental impact

Bio-derived carbon-based materials for sustainable environmental remediation and wastewater treatment

Biosynthesized nanocomposites, particularly those incorporating carbon-based materials, exhibit exceptional tunability and multifunctionality, surpassing the capabilities of conventional materials in these aspects. Developing practical solutions is critical to address environmental toxins from pharmaceuticals, heavy metals, pesticides, and dyes. Biomass waste is a readily available carbon source, which emerges as a promising material for producing biochar due to its inherent advantages: abundance, low cost, and environmentally friendly nature. This distribution mainly uses carbon-based materials (CBMs) and biomass waste in wastewater treatment. This review paper investigates several CBM types, including carbon aerogels, nanotubes, graphene, and activated carbon. The development of bio-derived carbon-based nanomaterials are discussed, along with the properties and composition of carbon materials derived from biomass waste and various cycles, such as photodegradation, adsorption, and high-level oxidation processes for natural remediation. In conclusion, this review examines the challenges associated with biochar utilization, including cost, recovery, and practical implementation.

Emerging bio-capture strategies for greenhouse gas reduction: Navigating challenges towards carbon neutrality

Greenhouse gas emissions are significantly contributing to climate change, posing one of the serious threats to our planet. Addressing these emissions urgently is imperative to prevent irreversible planetary changes. One effective long-term mitigation strategy is achieving carbon neutrality. Although numerous countries aim for carbon neutrality by 2050, only a few are on track to realize this ambition. Existing technological solutions, including chemical absorption, cryogenic separation, and membrane separation, are available but tend to be costly and time intensive. Bio-capture methods present a promising opportunity in greenhouse gas mitigation research. Recent developments in biotechnology for capturing greenhouse gases have demonstrated both effectiveness and long-term benefits. This review emphasizes the recent advancements in bio-capture techniques, showcasing them as dependable and economical solutions for carbon neutrality. The article briefly outlines various bio-capture methods and underscores their potential for industrial application. Moreover, it investigates into the challenges faced when integrating bio-capture with carbon capture and storage technology. The study concludes by exploring the recent trends and prospective enhancements in ecosystem revitalization and industrial decarbonization through green conversion techniques, reinforcing the path towards carbon neutrality.

Purification, biochemical characterization, and biotechnological applications of a multifunctional enzyme from the Thermoascus aurantiacus PI3S3 strain

The filamentous Thermoascus aurantiacus fungus characterized by its thermophilic nature, is recognized as an exceptional producer of various enzymes with biotechnological applications. This study aimed to explore biotechnological applications using polygalacturonase (PG) derived from the Thermoascus aurantiacus PI3S3 strain. PG production was achieved through submerged fermentation and subsequent purification via ion-exchange chromatography and gel filtration methods. The crude extract exhibited a diverse spectrum of enzymatic activities including amylase, cellulase, invertase, pectinase, and xylanase. Notably, it demonstrated the ability to hydrolyze sugarcane bagasse biomass, corn residue, and animal feed. The purified PG had a molecular mass of 36 kDa, with optimal activity observed at pH 4.5 and 70 °C. The activation energy (Ea) was calculated as 0.513 kJ mol-1, highlighting activation in the presence of Ca2+. Additionally, it displayed apparent Km, Vmax, and Kcat values of at 0.19 mg mL-1, 273.10 U mL-1, and 168.52 s-1, respectively, for hydrolyzing polygalacturonic acid. This multifunctional PG exhibited activities such as denim biopolishing, apple juice clarification, and demonstrated both endo- and exo-polygalacturonase activities. Furthermore, it displayed versatility by hydrolyzing polygalacturonic acid, carboxymethylcellulose, and xylan. The T. aurantiacus PI3S3 multifunctional polygalacturonase showed heightened activity under acidic pH, elevated temperatures, and in the presence of calcium. Its multifunctional nature distinguished it from other PGs, significantly expanding its potential for diverse biotechnological applications.

Biotechnological innovations in nanocellulose production from waste biomass with a focus on pineapple waste

New materials' synthesis and utilization have shown many critical challenges in healthcare and other industrial sectors as most of these materials are directly or indirectly developed from fossil fuel resources. Environmental regulations and sustainability concepts have promoted the use of natural compounds with unique structures and properties that can be biodegradable, biocompatible, and eco-friendly. In this context, nanocellulose (NC) utility in different sectors and industries is reported due to their unique properties including biocompatibility and antimicrobial characteristics. The bacterial nanocellulose (BNC)-based materials have been synthesized by bacterial cells and extracted from plant waste materials including pineapple plant waste biomass. These materials have been utilized in the form of nanofibers and nanocrystals. These materials are found to have excellent surface properties, low density, and good transparency, and are rich in hydroxyl groups for their modifications to other useful products. These materials are well utilized in different sectors including biomedical or health care centres, nanocomposite materials, supercapacitors, and polymer matrix production. This review explores different approaches for NC production from pineapple waste residues using biotechnological interventions, approaches for their modification, and wider applications in different sectors. Recent technological developments in NC production by enzymatic treatment are critically discussed. The utilization of pineapple waste-derived NC from a bioeconomic perspective is summarized in the paper. The chemical composition and properties of nanocellulose extracted from pineapple waste may have unique characteristics compared to other sources. Pineapple waste for nanocellulose production aligns with the principles of sustainability, waste reduction, and innovation, making it a promising and novel approach in the field of nanocellulose materials.

Whole-cell bioreporter application for rapid evaluation of hazardous metal bioavailability and toxicity in bioprocess

Assessing heavy metal bioavailability and toxicity during bioprocess is critical for advancing green biotechnology. The capability of whole-cell bioreporters to measure heavy metal bioavailability has been increasingly recognized. The advantages of this technology being applied to bioprocess monitoring are less studied. Here we investigate the potential of a cadmium- and lead-sensitive bioreporter to be used for heavy metals as a class, which holds great interest for bioprocess applications. We evaluated the bioavailability of eight individual heavy metals with bioreporter zntA, as well as the bioavailability and toxicity of mixed metals. The bioavailability and toxicity of heavy metals in bioprocess samples were also evaluated. We have demonstrated for the first time that the zntA bioreporter can effectively detect the bioavailability of zinc, nickel, and cobalt with limit of detection lower than 0.01, 0.08 and 0.5 mg·L-1, respectively. The detection limits meet the requirements of the WHO, the U.S. Environmental Protection Agency, and the China drinking water quality standards, which makes this approach reasonable for monitoring heavy metal bioavailability in bioprocess. LIVE/DEAD toxicity experiments have been conducted for the detection of mixed metal solution toxicity to zntA bioreporter which shows an EC50 (as EC50, concentration for 50% of maximal effect) value of mixed metal solution is 3.84 mg·L-1. Samples from wastewater treatment plants, sludge treatment plants and kitchen waste fermentation processes were analyzed to extend upon the laboratory results. The results of this study confirm the potential for practical applications of bioreporter technology in bioprocess monitoring. In turn, development for such practical applications is key to achieve the necessary level of commercialization to further make the routine use of bioreporters in bioprocess monitoring feasible.

Characterization of sugarcane mutants developed through gamma irradiations for their lignin content and caffeic acid-O-methyl transferase (COMT) gene mutations

PURPOSE

Bagasse, the residue left after extracting juice from sugarcane stalks, is rich in lignocellulosic biomass. The lignin present in this plant biomass is the key factor that hinders the efficient extraction of ethanol from the bagasse. In the current study, γ-irradiated sugarcane mutants were evaluated for variation in lignin content and its corresponding caffeic acid-O-methyl transferase (COMT) gene.

MATERIALS AND METHODS

The acetyl bromide method was used to estimate lignin content in sugarcane mutants. PCR-based cloning of the COMT gene was performed in low lignin mutants as well as control plants in E. coli (strain DH5α) to understand the mechanism of variation at the molecular level. The Sanger sequencing for cloned gene was performed to check variation in gene sequence.

RESULTS

In comparison to the control (21.5%), the mutant plants' lignin content ranged from 13 to 28%. The Sanger sequencing revealed approximately the same length of the gene from mutants as well as a control plant. In comparison to the reference gene, the mutated gene showed SNPs and indels in different regions, which may have an impact on lignin content.

CONCLUSIONS

Therefore, γ-irradiated mutagenesis is an acceptable approach to develop novel mutants of sugarcane with low lignin content to enhance bioethanol production from waste material using bioprocess technology.

Enzyme characterization of lactic acid bacteria isolated from duck excreta

Background and Aim

The production of lignocellulosic biomass waste in the agricultural sector of Indonesia is quite high annually. Utilization of lignocellulosic biomass waste through fermentation technology can be used as feed and biofuel. Fermentation technology requires the involvement of micro-organisms such as bacteria (lactic acid bacteria or LAB). LABs can be isolated from various sources, such as duck excreta. However, there have not been many reports of LAB from duck excreta. The present study aimed to characterize LAB enzymes isolated from duck excreta and obtain LAB enzymes with superior fermentation properties.

Materials and Methods

A total of 11 LAB cultures obtained from duck excreta in Yogyakarta, Indonesia, were tested. Enzyme characterization of each LAB was performed using the API ZYM kit (BioMérieux, Marcy-I'Etoile, France). The bacterial cell suspension was dropped onto the API ZYM™ cupule using a pipette and incubated for 4 h at 37°C. After incubation, ZYM A and ZYM B were dripped onto the API ZYM cupule, and color changes were observed for approximately 10 s under a strong light source.

Results

Esterase activity was moderate for all LABs. The activity of α-chymotrypsin, β-glucuronidase, α-fucosidase, and α-mannosidase was not observed in a total of 10 LAB. The phosphohydrolase and amino peptidase enzyme activity of seven LABs was strong. Only six LAB samples showed protease activity. The glycosyl hydrolase (GH) activity was observed in a total of 8 LAB, while the activity of 2 LAB was strong (Lactococcus lactis subsp. lactis K5 and Lactobacillus brevis M4A).

Conclusion

A total of 2 LABs have superior properties. L. lactis subsp. lactis K5 and L. brevis M4A have a high potential to be used in fermentation. They have the potential for further research, such as their effectiveness in fermentation, lignocellulose hydrolysis, feed additives, molecular characterization to detect specific enzymes, and their specific activities.

Microbial Pigments: Major Groups and Industrial Applications

Microbial pigments have many structures and functions with excellent characteristics, such as being biodegradable, non-toxic, and ecologically friendly, constituting an important source of pigments. Industrial production presents a bottleneck in production cost that restricts large-scale commercialization. However, microbial pigments are progressively gaining popularity because of their health advantages. The development of metabolic engineering and cost reduction of the bioprocess using industry by-products opened possibilities for cost and quality improvements in all production phases. We are thus addressing several points related to microbial pigments, including the major classes and structures found, the advantages of use, the biotechnological applications in different industrial sectors, their characteristics, and their impacts on the environment and society.

Valorization of onion peel waste: From trash to treasure

Globally, fruits and vegetables are consumed as raw, processed, or as an additive, accounting for approximately 50% of total food wastage. Among the fruits and vegetables, onion is well known for its potential bioactive components; however, peels of onion are a major concern for the environmental health and food industries. Effective utilization methods for valorizing the onion peel should be needed to develop value-added products, which are more eco-friendly, cost-effective, and sustainable. Therefore, this review attempts to emphasize the conventional and emerging valorization techniques for onion peel waste to generate value-added products. Several vital applications including anticancerous, antiobesity, antimicrobial, and anti-inflammatory activities are thoroughly discussed. The findings showed that the use of advanced technologies like ultrasound-assisted extraction, microwave-assisted extraction, and enzymatic extraction, demonstrated improved extraction efficiency and higher yield of bioactive compounds, which showed the anticancerous, antiobesity, antimicrobial, and anti-inflammatory properties. However, in-depth studies are recommended to elucidate the mechanisms of action and potential synergistic effects of the bioactive compounds derived from onion peel waste, and to promote the sustainable utilization of onion peel waste in the long-term.

Combined sulfuric acid and choline chloride/glycerol pretreatment for efficiently enhancing enzymatic saccharification of reed stalk

In this study, an efficient combination of pretreatment solvents involving Choline chloride/Glycerol (ChCl/Gly) and H2SO4 was firstly developed to assess the pretreatment performance and determine optimal pretreatment conditions. The results illustrated that the H2SO4-[ChCl/Gly] combination efficiently removed lignin (52.6%) and xylan (80.5%) from the pretreated reed stalk, and subsequent enzymatic hydrolysis yielded 91.1% of glucose. Furthermore, several characterizations were conducted to examine the structural and morphological changes of the reed stalk, revealing apparently enhanced accessibility (128.4 to 522.6 mg/g), reduced lignin surface area (357.9 to 229.5 m2/g), and substantial changes on biomass surface. Based on the aforementioned study, possible mechanisms for the H2SO4-[ChCl/Gly] pretreatment of reed stalks were proposed. The comprehensive understanding of combined H2SO4-[ChCl/Gly] pretreatment system for enhancing the saccharification of the reed stalk was interpreted in this work. Overall, this novel approach could be efficiently applied to pretreat and saccharify reed stalks, empowering the biomass refining industry.

Microwave-assisted depolymerization of chitin and chitosan extracted from crayfish shells waste: A sustainable approach based on graphene oxide catalysis

This study targeted the sustainable utilization of chitin and chitosan from crayfish shell waste, and further depolymerization of the recovered products in one step through synergy between microwaves and graphene oxide, aiming for the monosaccharides, 5-hydroxymethylfurfural and other high-value products. The results indicated that graphene oxide was more effective than graphene in enhancing the microwave absorption properties of the system, which is contrary to the parameters of their dielectric properties. The heating rate was increased by 0.37 K/s and 0.26 K/s when graphene oxide was introduced into the chitin and chitosan depolymerization systems, respectively, at a microwave power of 5 W/g. The mechanism underlying the impact of graphene oxide on chitin and chitosan under a microwave field was proposed by analyzing the variations in the depolymerization products of chitin and chitosan systems under different reaction conditions, including holding time, catalyst content, solvent content, and reaction temperature. Furthermore, the recovered graphene oxide exhibited delamination upon redispersion in water, which was not observed in the initial samples. The infrared spectra and scanning electron microscopy results suggest that the catalytic reaction is associated with oxygen-containing functional groups. This study demonstrated the synergistic effect of microwaves and graphene oxide on the depolymerization of chitin and chitosan, and the ability to achieve rapid one-step depolymerization in an acid/alkali-free solvent, which provides a green and promising development for the degradation of carbohydrate macromolecules in crustacean solid waste.

Chemobiocatalytic transfromation of biomass into furfurylamine with mixed amine donor in an eco-friendly medium

Biobased furfurylamine (FAM) is a versatile platform molecule for producing additives, pharmaceuticals, and pesticides. Recombinant E. coli HNND-AlaDH was created by co-expressing L-alanine dehydrogenase (AlaDH) and mutated Aspergillus terreus ω-transaminase (HNND), aiming to convert furfural (FUR) into FAM using inexpensive L-alanine and isopropylamine as mixed amine donors. In ChCl:FA:OA (10 wt%), pineapple peel, bagasse, barley shell, peanut shell, and corn stalk could be efficiently transformed into FUR under 170 °C for 10 min. Pineapple peel produced a high titer of FUR (183.3 mM). Additionally, the viscosity, surface tension and polarity of ChCl:FA:OA were explored. The biomass-derived FUR was fully transformed to FAM by HNND-AlaDH with amine donor (1:1:1 of L-Ala/isopropylamine/FUR mol/mol/mol) within 300 min. Accordingly, the FAM productivity was 0.58 g/(g xylan in pineapple peel). This chemobiocatalytic strategy established through the combination of chemocatalysis and biocatalysis could be applied to convert renewable biomass into valuable organic amines.

Development of a magnetically stabilized fluidized bed bioreactor for enzymatic synthesis of 2-ethylhexyl oleate

This study aimed to develop and investigate the synthesis of 2-ethylhexyl oleate catalyzed by Candida antarctica lipase immobilized on magnetic poly(styrene-co-divinylbenzene) (STY-DVB-M) particles in a magnetically stabilized fluidized bed reactor (MSFBR) operated in continuous mode. The physical properties of the copolymer were characterized by Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The glass transition temperature was 85.68 °C, and the onset of thermal degradation occurred at 406.66 °C. Syntheses were performed at 50 °C using a space time of 12 h and a bed porosity of 0.892. Assays were conducted to assess the influence of magnetic field intensity (5 to 15 mT) on reaction yield, ester concentration, and productivity. The highest productivity was 0.850 ± 0.023 mmol g-1 h-1, obtained with a magnetic field intensity of 15 mT. An operational stability test was performed under these conditions, revealing a biocatalyst half-life of 2148 h (179 operation cycles) and a thermal deactivation constant of 3.23 × 10-4 h-1 (R2 = 0.9446). Computational simulations and mathematical modeling were performed using Scilab based on ping-pong bi-bi kinetics and molar balances of reaction species. The model provided consistent results of interstitial velocity and good prediction of reaction yields, with R2 = 0.926. These findings demonstrate that the studied technique can provide improvements in biocatalytic processes, representing a promising strategy for the enzymatic synthesis of 2-ethylhexyl oleate.

Improved biotransformation of lignin-valorized vanillin into vanillylamine in a sustainable bioreaction medium

Lignin is a critical biopolymer for creating a large number of highly valuable biobased compounds. Vanillin, one of lignin-derived aromatics, can be used to synthesize vanillylamine that is a key fine chemical and pharmaceutical intermediate. To produce vanillylamine, a productive whole-cell-catalyzed biotransformation of vanillin was developed in deep eutectic solvent - surfactant - H2O media. One newly created recombinant E. coli 30CA cells expressing ω-transaminase and L-alanine dehydrogenase was employed to transform 50 mM and 60 mM vanillin into vanillylamine in the yield of 82.2% and 8.5% under 40 °C, respectively. The biotransamination efficiency was enhanced by introducing surfactant PEG-2000 (40 mM) and deep eutectic solvent ChCl:LA (5.0 wt%, pH 8.0), and the highest vanillylamine yield reached 90.0% from 60 mM vanillin. Building an effective bioprocess was utilized for transamination of lignin-derived vanillin to vanillylamine with newly created bacteria in an eco-friendly medium, which had potential application for valorization of lignin to value-added compounds.

Biological valorization of lignin-derived vanillin to vanillylamine by recombinant E. coli expressing ω-transaminase and alanine dehydrogenase in a petroleum ether-water system

Vanillylamine, as an important drug precursor and fine chemical intermediate, has great economic value. By constructing a strategy of double enzyme co-expression, one newly constructed recombinant E. coli HNIQLE-AlaDH expressing ω-transaminase from Aspergillus terreus and alanine dehydrogenase from Bacillus subtilis was firstly used aminate lignin-derived vanillin to vanillylamine by using a relatively low dosage of amine donors (vanillin:L-alanine:isopropylamine = 1:1:1, mol/mol/mol). In addition, in a two-phase system (water:petroleum ether = 80:20 v/v), the bioconversion of vanillin to vanillylamine was catalyzed by HNIQLE-AlaDH cell under the ambient condition, and the vanillylamine yield was 71.5%, respectively. This double-enzyme HNIQLE-AlaDH catalytic strategy was applied to catalyze the bioamination of furfural and 5-hydroxymethylfurfural with high amination efficiency. It showed that the double-enzyme catalytic strategy in this study promoted L-alanine to replace D-Alanine to participate in bioamination of vanillin and its derivatives, showing a great prospect in the green biosynthesis of biobased chemicals from biomass.

A strategic review on sustainable approaches in municipal solid waste management andenergy recovery: Role of artificial intelligence,economic stability andlife cycle assessment

The consumption of energy levels has increased in association with economic growth and concurrently increased the energy demand from renewable sources. The need under Sustainable Development Goals (SDG) intends to explore various technological advancements for the utilization of waste to energy. Municipal Solid Waste (MSW) has been reported as constructive feedstock to produce biofuels, biofuel carriers and biochemicals using energy-efficient technologies in risk freeways. The present review contemplates risk assessment and challenges in sorting and transportation of MSW and different aspects of conversion of MSW into energy are critically analysed. The circular bioeconomy of energy production strategies and management of waste are also analysed. The current scenario on MSW and its impacts on the environment are elucidated in conjunction with various policies and amendments equipped for the competent management of MSW in order to fabricate a sustained environment.

Valorization of Biomass-Derived Polymers to Functional Biochar Materials for Supercapacitor Applications via Pyrolysis: Advances and Perspectives

Polymers from biomass waste including plant/forest waste, biological industrial process waste, municipal solid waste, algae, and livestock are potential sources for renewable and sustainable resources. Converting biomass-derived polymers to functional biochar materials via pyrolysis is a mature and promising approach as these products can be widely utilized in many areas such as carbon sequestration, power production, environmental remediation, and energy storage. With abundant sources, low cost, and special features, the biochar derived from biological polymeric substances exhibits great potential to be an alternative electrode material of high-performance supercapacitors. To extend this scope of application, synthesis of high-quality biochar will be a key issue. This work systematically reviews the char formation mechanisms and technologies from polymeric substances in biomass waste and introduces energy storage mechanisms of supercapacitors to provide overall insight into the biological polymer-based char material for electrochemical energy storage. Aiming to enhance the capacitance of biochar-derived supercapacitor, recent progress in biochar modification approaches including surface activation, doping, and recombination is also summarized. This review can provide guidance for valorizing biomass waste to functional biochar materials for supercapacitor to meet future needs.

Fungal Biotransformation of Hazardous Organic Compounds in Wood Waste

A diverse spectrum of organisms, such as fungi, bacteria, and actinomycetes, can degrade and transform organic matter, including wood, into valuable nutrients. A sustainable economy has the goal of efficiently using waste as raw materials, and in this optic, it uses biological preparations more and more often, supporting the decomposition of lignocellulosic waste. With reference to wood wastes, which are produced in a substantial amount by the forest and wood industry, one of the possibilities to biodegrade such lignocellulosic material is the composting process. In particular, microbiological inoculum containing dedicated fungi can contribute to the biodegradation of wood waste, as well as the biotransformation of substances from the protection of wood, such as pentachlorophenol (PCP), lindane (hexachlorobenzene) and polycyclic aromatic hydrocarbons (PAHs). The purpose of this research was to produce a literature review in terms of the selection of decay fungi that could potentially be used in toxic biotransformation unions. The findings of the literature review highlighted how fungi such as Bjerkandera adusta, Phanerochaete chrysosporium, and Trametes versicolor might be ingredients of biological consortia that can be effectively applied in composting wood waste containing substances such as pentachlorophenol, lindane, and polycyclic aromatic hydrocarbons (PAHs).

Intelligent approaches for sustainable management and valorisation of food waste

Food waste (FW) is a severe environmental and social concern that today's civilization is facing. Therefore, it is necessary to have an efficient and sustainable solution for managing FW bioprocessing. Emerging technologies like the Internet of Things (IoT), Artificial Intelligence (AI), and Machine Learning (ML) are critical to achieving this, in which IoT sensors' data is analyzed using AI and ML techniques, enabling real-time decision-making and process optimization. This work describes recent developments in valorizing FW using novel tactics such as the IoT, AI, and ML. It could be concluded that combining IoT, AI, and ML approaches could enhance bioprocess monitoring and management for generating value-added products and chemicals from FW, contributing to improving environmental sustainability and food security. Generally, a comprehensive strategy of applying intelligent techniques in conjunction with government backing can minimize FW and maximize the role of FW in the circular economy toward a more sustainable future.

3D-Printed PLA Molds for Natural Composites: Mechanical Properties of Green Wax-Based Composites

The first part of this paper is dedicated to obtaining 3D-printed molds using poly lactic acid (PLA) incorporating specific patterns, which have the potential to serve as the foundation for sound-absorbing panels for various industries and aviation. The molding production process was utilized to create all-natural environmentally friendly composites. These composites mainly comprise paper, beeswax, and fir resin, including automotive function as the matrices and binders. In addition, fillers, such as fir needles, rice flour, and Equisetum arvense (horsetail) powder, were added in varying amounts to achieve the desired properties. The mechanical properties of the resulting green composites, including impact and compressive strength, as well as maximum bending force value, were evaluated. The morphology and internal structure of the fractured samples were analyzed using scanning electron microscopy (SEM) and an optical microscopy. The highest impact strength was measured for the composites with beeswax, fir needles, recyclable paper, and beeswax fir resin and recyclable paper, 19.42 and 19.32 kJ/m², respectively, while the highest compressive strength was 4 MPa for the beeswax and horsetail-based green composite. Natural-material-based composites exhibited 60% higher mechanical performance compared to similar commercial products used in the automotive industry.

Genome-guided approaches and evaluation of the strategies to influence bioprocessing assisted morphological engineering of Streptomyces cell factories

Streptomyces genera serve as adaptable cell factories for secondary metabolites with various and distinctive chemical structures that are relevant to the pharmaceutical industry. Streptomyces' complex life cycle necessitated a variety of tactics to enhance metabolite production. Identification of metabolic pathways, secondary metabolite clusters, and their controls have all been accomplished using genomic methods. Besides this, bioprocess parameters were also optimized for the regulation of morphology. Kinase families were identified as key checkpoints in the metabolic manipulation (DivIVA, Scy, FilP, matAB, and AfsK) and morphology engineering of Streptomyces. This review illustrates the role of different physiological variables during fermentation in the bioeconomy coupled with genome-based molecular characterization of biomolecules responsible for secondary metabolite production at different developmental stages of the Streptomyces life cycle.

From trash to treasure: Sourcing high-value, sustainable cellulosic materials from living bioreactor waste streams

The appreciation of how conventional and fossil-based materials could be harmful to our planet is growing, especially when considering single-use and non-biodegradable plastics manufactured from fossil fuels. Accordingly, tackling climate change and plastic waste pollution entails a more responsible approach to sourcing raw materials and the adoption of less destructive end-of-life pathways. Livestock animals, in particular ruminants, process plant matter using a suite of mechanical, chemical and biological mechanisms through the act of digestion. The manure from these "living bioreactors" is ubiquitous and offers a largely untapped source of lignocellulosic biomass for the development of bio-based and biodegradable materials. In this review, we assess recent studies made into manure-based cellulose materials in terms of their material characteristics and implications for sustainability. Despite the surprisingly diverse body of research, it is apparent that progress towards the commercialisation of manure-derived cellulose materials is hindered by a lack of truly sustainable options and robust data to assess the performance against conventional materials alternatives. Nanocellulose, a natural biopolymer, has been successfully produced by living bioreactors and is presented as a candidate for future developments. Life cycle assessments from non-wood sources are however minimal, but there are some initial indications that manure-derived nanocellulose would offer environmental benefits over traditional wood-derived sources.

The Preparation Processes and Influencing Factors of Biofuel Production from Kitchen Waste

Kitchen waste is an important component of domestic waste, and it is both harmful and rich in resources. Approximately 1.3 billion tons of kitchen waste are produced every year worldwide. Kitchen waste is high in moisture, is readily decayed, and has an unpleasant smell. Environmental pollution can be caused if this waste is treated improperly. Conventional treatments of kitchen waste (e.g., landfilling, incineration and pulverization discharge) cause environmental, economic, and social problems. Therefore, the development of a harmless and resource-based treatment technology is urgently needed. Profits can be generated from kitchen waste by converting it into biofuels. This review intends to highlight the latest technological progress in the preparation of gaseous fuels, such as biogas, biohythane and biohydrogen, and liquid fuels, such as biodiesel, bioethanol, biobutanol and bio-oil, from kitchen waste. Additionally, the pretreatment methods, preparation processes, influencing factors and improvement strategies of biofuel production from kitchen waste are summarized. Problems that are encountered in the preparation of biofuels from kitchen waste are discussed to provide a reference for its use in energy utilization. Optimizing the preparation process of biofuels, increasing the efficiency and service life of catalysts for reaction, reasonably treating and utilizing the by-products and reaction residues to eliminate secondary pollution, improving the yield of biofuels, and reducing the cost of biofuels, are the future directions in the biofuel conversion of kitchen waste.

Environmental implications of reprocessing agricultural waste into animal food: An experience with rice straw and citrus pruning waste

The aim of this study is to conduct an environmental comparison, by applying the life cycle assessment (LCA) methodology, of two different compositions for animal foods each with two different nutritional contents ('high' for the lactation period, and 'low' for the rest of the year). Thus, for each nutritional content, the environmental performance of producing animal feed with a traditional composition mainly based on cereals is compared with a composition based on a mixture of biomass obtained from rice straw and citrus pruning waste. It was observed that the reprocessing of rice straw and citrus pruning waste into animal feed offered environmental potential compared to the current alternative of being burned in the fields. The environmental impact category global warming is especially improved, with impact reductions of up to 50% and 95%, respectively, for high and low nutritional content compositions. In addition, the alternatives proposed herein make it possible to avoid all the inconvenience and impacts on the health of the population living near the fields.

An efficient chemoenzymatic cascade strategy for transforming biomass into furfurylamine with lobster shell-based chemocatalyst and mutated ω-transaminase biocatalyst in methyl isobutyl ketone-water

To date, an efficient process for manufacturing valuable furan compounds from available renewable resources has gained great attention via a chemoenzymatic route. In this study, a sulfonated tin-loaded heterogeneous catalyst CLUST-Sn-LS using lobster shell as biobased carrier was prepared to convert corncob (75.0 g/L) into furfural (122.5 mM) at 170 °C for 30 min in methyl isobutyl ketone (MIBK)-H₂O biphasic system (2:1, v/v). To improve furfurylamine yield, a novel recombinant E. coli TFTS harboring robust mutant Aspergillus terreus ω-transaminase [hydrophilic threonine (T) at position 130 was site-directed mutated to hydrophobic phenylalanine (F)] was constructed to transform 300-500 mM furfural into furfurylamine (90.1-93.6 % yield) at 30 °C and pH 7.5 in MIBK-H₂O. Corncob was converted to furfurylamine in MIBK-H₂O with a high productivity of 0.461 g furfurylamine/(g xylan). This constructed chemoenzymatic method coupling bio-based chemocatalyst CLUST-Sn-LS and mutant ω-transaminase biocatalyst in a biphasic system could efficiently convert lignocellulose into furfurylamine.

Value addition through biohydrogen production and integrated processes from hydrothermal pretreatment of lignocellulosic biomass

Bioenergy production is the most sought-after topics at the crunch of energy demand, climate change and waste generation. In view of this, lignocellulosic biomass (LCB) rich in complex organic content has the potential to produce bioenergy in several forms following the pretreatment. Hydrothermal pretreatment that employs high temperatures and pressures is gaining momentum for organics recovery from LCB which can attain value-addition. Diverse bioprocesses such as dark fermentation, anaerobic digestion etc. can be utilized following the pretreatment of LCB which can result in biohydrogen and biomethane production. Besides, integration approaches for LCB utilization that enhance process efficiency and additional products such as biohythane production as well as application of solid residue obtained after LCB pretreatment were discussed. Importance of hydrothermal pretreatment as one of the suitable strategies for LCB utilization is emphasized suggesting its future potential in large scale energy recovery.

Green synthesis of silica and silicon from agricultural residue sugarcane bagasse ash - a mini review

Silicon dioxide (SiO₂), also known as silica, has received attention in recent years due to wide range of capable applications including biomedical/pharmaceutical, energy, food, and personal care products. This has accelerated research in the extraction of materials from various agricultural wastes; this review investigates the extraction of silica and silicon nanoparticles from sugarcane bagasse ash with potential applications in electronic devices. Specific properties of silica have attracted the interest of researchers, which include surface area, size, biocompatibility, and high functionality. The production of silica from industrial agricultural waste exhibits sustainability and potential reduction in waste production. Bagasse is sustainable and environmentally friendly; though considered waste, it could be a helpful component for sustainable progress and further technological advancement. The chemical, biogenic and green synthesis are discussed in detail for the production of silica. In green synthesis, notable attempts have been made to replace toxic counterparts and decrease energy usage with the same quantity and quality of silica obtained. Methods of reducing silica to silicon are also discussed with the potential application-specific properties in electronic devices, and modern technological applications, such as batteries, supercapacitors, and solar cells.

Cellulosic pine needles-based biorefinery for a circular bioeconomy

Pine needles (PNs) are one of the largest bio-polymer produced worldwide. Its waste, i.e., fallen PNs, is mostly responsible for forest fires and is a major challenge. In present article, we have reviewed differenteffortsmadeto tackle this situation. PNs have been used in various fields such asin composite, water purification industries,electronic devices, etc. Gasification is one of the appealing processes for turning PNs into bio-energy; pyrolysis technique has been employed to create various carbon-based water purification materials; saccharification combined with fermentation produced good yields of bio-ethanol; Pd or Ni/PNs biocatalyst showed good catalytic properties in variousreactionsand pyrolysis with or without catalyst is an alluring technique to prepare bio-fuel. Nano cellulose extracted from PNs showed appealing thermal and mechanical strength. The air quality of nearbyenvironment was examinedby studying the magnetic properties of PNs. Packing materials made of PNs showed exceptional ethylene scavenging abilities.

A comprehensive review on the advances of bioproducts from biomass towards meeting net zero carbon emissions (NZCE)

This review investigates the development of bioproducts from biomass and their contribution towards net zero carbon emissions. The promising future of biomasses conversion techniques to produce bioproducts was reviewed. The advances in anaerobic digestion as a biochemical conversion technique have been critically studied and contribute towards carbon emissions mitigation. Different applications of microalgae biomass towards carbon neutrality were comprehensively discussed, and several research findings have been tabulated in this review. The carbon footprints of wastewater treatment plants were studied, and bioenergy utilisation from sludge production was shown to mitigate carbon footprints. The carbon-sinking capability of microalgae has also been outlined. Furthermore, integrated conversion processes have shown to enhance bioproducts generation yield and quality. The anaerobic digestion/pyrolysis integrated process was promising, and potential substrates have been suggested for future research. Lastly, challenges and future perspectives of bioproducts were outlined for a contribution towards meeting carbon neutrality.

Recent advances in biogas production using Agro-Industrial Waste: A comprehensive review outlook of Techno-Economic analysis

Agrowaste sources can be utilized to produce biogas by anaerobic digestion reaction. Fossil fuels have damaged the environment, while the biogas rectifies the issues related to the environment and climate change problems. Techno-economic analysis of biogas production is followed by nutrient recycling, reducing the greenhouse gas level, biorefinery purpose, and global warming effect. In addition, biogas production is mediated by different metabolic reactions, the usage of different microorganisms, purification process, upgrading process and removal of CO₂ from the gas mixture techniques. This review focuses on pre-treatment, usage of waste, production methods and application besides summarizing recent advancements in biogas production. Economical, technical, environmental properties and factors affecting biogas production as well as the future perspective of bioenergy are highlighted in the review. Among all agro-industrial wastes, sugarcane straw produced 94% of the biogas. In the future, to overcome all the problems related to biogas production and modify the production process.

Deep Eutectic Solvents: Alternative Solvents for Biomass-Based Waste Valorization

Innovative technologies can transform what are now considered “waste streams” into feedstocks for a range of products. Indeed, the use of biomass as a source of biopolymers and chemicals currently has a consolidated economic dimension, with well-developed and regulated markets, in which the evaluation of the manufacturing processes relies on specific criteria such as purity and yield, and respects defined regulatory parameters for the process safety. In this context, ionic liquids and deep eutectic solvents have been proposed as environmentally friendly solvents for applications related to biomass waste valorization. This mini-review draws attention to some recent advancements in the use of a series of new-solvent technologies, with an emphasis on deep eutectic solvents (DESs) as key players in the development of new processes for biomass waste valorization. This work aims to highlight the role and importance of DESs in the following three strategic areas: chitin recovery from biomass and isolation of valuable chemicals and biofuels from biomass waste streams.

Ionic Liquid-Based Polymer Nanocomposites for Sensors, Energy, Biomedicine, and Environmental Applications: Roadmap to the Future

Current interest toward ionic liquids (ILs) stems from some of their novel characteristics, like low vapor pressure, thermal stability, and nonflammability, integrated through high ionic conductivity and broad range of electrochemical strength. Nowadays, ionic liquids represent a new category of chemical-based compounds for developing superior and multifunctional substances with potential in several fields. ILs can be used in solvents such as salt electrolyte and additional materials. By adding functional physiochemical characteristics, a variety of IL-based electrolytes can also be used for energy storage purposes. It is hoped that the present review will supply guidance for future research focused on IL-based polymer nanocomposites electrolytes for sensors, high performance, biomedicine, and environmental applications. Additionally, a comprehensive overview about the polymer-based composites' ILs components, including a classification of the types of polymer matrix available is provided in this review. More focus is placed upon ILs-based polymeric nanocomposites used in multiple applications such as electrochemical biosensors, energy-related materials, biomedicine, actuators, environmental, and the aviation and aerospace industries. At last, existing challenges and prospects in this field are discussed and concluding remarks are provided.

Melioration of Paddy Straw to produce cellulase-free xylanase and bioactives under Solid State Fermentation and deciphering its impact by Life Cycle Assessment

Aiming towards zero waste management of Paddy straw (PS), the study offers a novel route for production of cellulase-free xylanase, using consortia of Trichoderma spp. under Solid State Fermentation (SSF) of PS valorized using nitrogen rich de-oiled neem cake (NC). Life Cycle Assessment (LCA) for enzyme production, performed using SimaPro software, depicted adverse impacts due to electricity consumption (92.84%) and use of ammonium sulphate salt (6.17%). Nonetheless, employing renewable energy and reducing salt consumption could help minimize these impacts. OHR-LCMS study of the partially purified enzyme revealed the presence of β-xylanase and α-L-Arabinofuranosidase. Enzymatic saccharification of various substrates enhanced the release of reducing sugars (mg/g) from corn cob (137.54 ± 0.96), pine needle (41.43 ± 1), sugarcane bagasse (105.17 ± 0.7), and PS (76.66 ± 1.29), demonstrating its applicability in the biofuel domain. LC-MS, ICMPS, and EDX profiling of the residual spent unravelled the manifestation of bioactives, minerals, and silica, playing an essential role as biopesticide and biofertilizer.

Production of bioethanol from food waste: Status and perspectives

There is an immediate global requirement for an ingenious strategy for food waste conversion to biofuels in order to replace fossil fuels with renewable resources. Food waste conversion to bioethanol could lead to a sustainable process having the dual advantage of resolving the issue of food waste disposal as well as meeting the energy requirements of the increasing population. Food waste is increasing at the rate of 1.3 billion tonnes per year, considered to be one-third of global food production. According to LCA studies discarding these wastes is detritus to the environment, therefore; it is beneficial to convert the food waste into bioethanol. The CO₂ emission in this process offers zero impact on the environment as it is biogenic. Among several pretreatment strategies, hydrothermal pretreatment could be a better approach for pretreating food waste because it solubilizes organic solids, resulting in an increased recovery of fermentable sugars to produce bioenergy.

Development of miniaturized agar based assays in 96-well microplates applicable to high-throughput screening of industrially valuable microorganisms

High-throughput screening (HTS) is a present-day approach for assaying thousands of cultures in parallel. This miniaturization allows rapid screening of large number of microorganims capable of producing bio-based materials thereby meeting the demands of the ever evolving food, pharmaceutical and cosmetic industry. In this study, agar-based assays for phosphate solubilization, cellulose degradation and lactic acid production were developed in 96-well microplates using Biomek FX^P Automated Liquid Handling system. Techno-economic analysis from this study reveals the lower overall cost per assay using HTS as compared to conventional Petri plate assays. Though automated liquid handling workstations have been used to perform liquid-based assays, there are very few studies which report their use for agar-based microplate assays. These findings thus corroborate the establishment of rapid and efficient miniaturized, qualitative agar-based screening methods for identifying microorganisms with potential for commercial application.

Investigation of non-isothermal pyrolysis kinetics of waste industrial hemp stem by three-parallel-reaction model

The evaluation of pyrolysis kinetics for waste industrial hemp stem (IHS) is essential to achieve the high-value utilization of agricultural waste. In present study, firstly, non-isothermal pyrolysis experiments of IHS were performed at different heating rates using a thermogravimetric analyzer. Then, the kinetic triplets (apparent activation energy, pre-exponential factor, and reaction mechanism) of the three pseudo components for IHS (hemicellulose, cellulose, and lignin) were determined by a three-parallel-reaction model. Moreover, the pyrolysis products were also characterized via FTIR and SEM. The results showed that the apparent activation energies of hemicellulose, cellulose and lignin were 86.523, 113.257 and 197.961 kJ/mol, respectively; the pre-exponential factors were 6.887 × 10⁷, 8.179 × 10⁹ and 1.801 × 10¹⁵ s^-1, respectively; and the reaction mechanism functions were f(α) = α^1.35629(1-α)^0.34832[-ln(1-α)]^-1.20128, f(α) = α^3.42900(1-α)^0.01288[-ln(1-α)]^-2.84445, f(α) = α^0.68738(1-α)^3.09313[-ln(1-α)]^-1.58522, respectively. The release temperature for volatile products of IHS pyrolysis was mainly between 440 and 840 K. IHS as an agricultural waste is a suitable feedstock to produce renewable energy.

Synthesis and characterisation of zinc oxide modified biorenewable polysaccharides based sustainable hydrogel nanocomposite for Hg2+ ion removal: Towards a circular bioeconomy

Industrial metal ion pollution has been considered the chief source of water contaminants all over the world. In the present research, we have prepared gum tragacanth cross-linked 2-hydroxyethyl methacrylate-co-acrylamide (GT-cl-(HEMA-co-AAm)) hydrogel and gum tragacanth cross-linked 2-hydroxyethyl methacrylate-co-acrylamide/zinc oxide (GT-cl-(HEMA-co-AAm)/ZnO) hydrogel composite with better Hg²⁺ adsorption capability. GT-cl-(HEMA-co-AAm)/ZnO hydrogel composite (154.8 mg g^-1) exhibited higher Hg²⁺ adsorption than GT-cl-(HEMA-co-AAm) hydrogel. To address the performance of GT-cl-(HEMA-co-AAm) hydrogel and GT-cl-(HEMA-co-AAm)/ZnO hydrogel composite, batch adsorption experiments were successfully conducted under different optimised conditions. At last, in-vitro antibacterial activities of Hg²⁺ loaded GT-cl-(HEMA-co-AAm) and GT-cl-(HEMA-co-AAm)/ZnO were performed in two different well Staphylococcus aureus (gram-positive) and Pseudomonas aeruginosa (gram-negative) bacteria. As a positive control, ampicillin was employed against both types of bacteria. This methodology for the reusability of material has a great ecofriendly impression for minimising secondary waste derived from adsorption and can help design upgraded antibacterial agents.

Valorization of agro-industrial biowaste to green nanomaterials for wastewater treatment: Approaching green chemistry and circular economy principles

Water pollution is one of the most critical issues worldwide and is a priority in all scientific agendas. Green nanotechnology presents a plethora of promising avenues for wastewater treatment. This review discusses the current trends in the valorization of zero-cost, biodegradable, and readily available agro-industrial biowaste to produce green bio-nanocatalysts and bio-nanosorbents for wastewater treatment. The promising roles of green bio-nanocatalysts and bio-nanosorbents in removing organic and inorganic water contaminants are discussed. The potent antimicrobial activity of bio-derived nanodisinfectants against water-borne pathogenic microbes is reviewed. The bioactive molecules involved in the chelation and tailoring of green synthesized nanomaterials are highlighted along with the mechanisms involved. Furthermore, this review emphasizes how the valorization of agro-industrial biowaste to green nanomaterials for wastewater treatment adheres to the fundamental principles of green chemistry, circular economy, nexus thinking, and zero-waste manufacturing. The potential economic, environmental, and health impacts of valorizing agro-industrial biowaste to green nanomaterials are highlighted. The challenges and future outlooks for the management of agro-industrial biowaste and safe application of green nanomaterials for wastewater treatment are summarized.

Humus Acids in the Digested Sludge and Their Properties

Fulvic acids, alpha (α) humic acids and hymatomelanic acids were extracted digested sludge in two Cracow sewage treatment plants: Kujawy and Płaszów. Their elemental composition was examined and micropollution and ash content were determined. Based on the IR and UV-VIS spectrum, their similarities were determined with the occurring interactions with micropollution. Strong correlations between the acids coming from different sources depend on acid type and micropollution accompanying them, depending on concentration, influences to a specific extent their IR and UV-VIS spectra. Absorption analysis in infrared constitutes a simple method for characterizing fulvic and humic acids from wastewater treatment plants. The extracted fulvic acids were characterized by moderate maturity, while humus acids were well developed. In the fermentation process, the N bond increases together with the level of humification of the humus acid. The characteristics of the extracted humus acids comply with other humic substances presented in the literature. Quantitative analysis showed that digested sludge contains, on average: FA from 5.07 to 5.30 g/kg dry matter, αHA from 59.22 to 74.72 g/kg dry matter, HMA from 20.31 to 43.66 g/kg dry matter. It was thus demonstrated that wastewater treatment, in particular digested sludge, constitutes an attractive source of humus acids with a wide range of applications in numerous areas, such as agriculture, ecological rehabilitation, environmental protection, animal breeding, aquaculture, veterinary as well as medicine and is a precious source of soil fertilizers.

Partnership for International Development: Finland-Argentina Conference on Circular Economy and Bioeconomy with Emphasis on Food Sovereignty and Sustainability

A joint collaboration between the Cuarto region of Argentina championed by the National University of Rio Cuarto and the Arctic Centre of the University of Lapland, Finland organised a conference on several topics that are related to food sovereignty, sustainability, circular economy and bioeconomy. The efficient utilisation of natural resources in both regions is an important theme in meeting the sustainable development goals agenda. Hence, this partnership between the partner institutions will lead to the cocreation of knowledge. The topics were multidisciplinary, and the discussion focussed on research and teaching opportunities for institutions in both countries. The experts from both countries will continue to engage on the possibility of promoting the research agenda in these important areas.

Valorization of sugar beet pulp to value-added products: A review

The processing of sugar beet in the sugar production industry releases huge amounts of sugar beet pulp as waste which can be considered a valuable by-product as a source of cellulose, hemicellulose, and pectin. Valorization of sugar beet pulp into value added products occurs through acid hydrolysis, hydrothermal techniques, and enzymatic hydrolysis. Biochemical conversion of beet pulp into simple fermentable sugars for producing value added products occurs through enzymatic hydrolysis is a cost effective and eco-friendly process. While beet pulp has predominantly been used as a fodder for livestock, recent developments in its biotechnological valorization have unlocked its value as a feedstock in the production of biofuels, biohydrogen, biodegradable plastics, and platform chemicals such as lactic acid, citric acid, alcohols, microbial enzymes, single cell proteins, and pectic oligosaccharides. This review brings forward recent biotechnological developments made in the valorization of sugar beet pulp into valuable products.

Saccharification of lignocellulosic biomass using an enzymatic cocktail of fungal origin and successive production of butanol by Clostridium acetobutylicum

A multistep approach was undertaken for biobutanol production targeting valorization of agricultural waste. Optimum production of lignocellulolytic enzymes [CMCase (3822.93U/mg), FPase (3640.93U/mg), β-glucosidase (3873.92U/mg), xylanase (3460.24U/mg), pectinase (3359.57U/mg), α-amylase (4136.54U/mg), and laccase (3863.16U/mg)] was accomplished through solid-substrate fermentation of pretreated mixed substrates (wheat bran, sugarcane bagasse and orange peel) by Aspergillus niger SKN1 and Trametes hirsuta SKH1. Partially purified enzyme cocktail was employed for saccharification of the said substrate mixture into fermentable sugar (69.23 g/L, product yield of 24% w/w). The recovered sugar with vegetable extract supplements was found as robust fermentable medium that supported 16.51 g/L biobutanol production by Clostridium acetobutylicum ATCC824. The sequential bioprocessing of low-priced substrates and exploitation of vegetable extract as growth factor for microbial butanol production will open a new vista in biofuel research.

Valorization of agro-industrial wastes for biorefinery process and circular bioeconomy: A critical review

Energy recovery from waste resources is a promising approach towards environmental consequences. In the prospect of environmental sustainability, utilization of agro-industrial waste residues as feedstock for biorefinery processes have gained widespread attention. In the agro-industry, various biomasses are exposed to different unit processes for offering value to various agro-industrial waste materials. Agro-industrial wastes can generate a substantial amount of valuable products such as fuels, chemicals, energy, electricity, and by-products. This paper reviews the methodologies for valorization of agro-industrial wastes and their exploitation for generation of renewable energy products. In addition, management of agro-industrial wastes and products from agro-industrial wastes have been elaborated. The waste biorefinery process using agro-industrial wastes does not only offer energy, it also offers environmentally sustainable modes, which address effective management of waste streams. This review aims to highlight the cascading use of biomass from agro-industrial wastes into the systemic approach for economic development.

Recent advances of thermochemical conversion processes for biorefinery

Lignocellulosic biomass is one of the most promising renewable resources and can replace fossil fuels via various biorefinery processes. Through this study, we addressed and analyzed recent advances in the thermochemical conversion of various lignocellulosic biomasses. We summarized the operation conditions and results related to each thermochemical conversion processes such as pyrolysis (torrefaction), hydrothermal treatment, gasification and combustion. This review indicates that using thermochemical conversion processes in biorefineries is techno-economically feasible, easy, and effective compared with biological processes. The challenges experienced in thermochemical conversion processes are also presented in this study for better understanding the future of thermochemical conversion processes for biorefinery. With the aid of artificial intelligence and machine learning, we can reduce time-consumption and experimental work for bio-oil production and syngas production processes.

Added-value biomolecules' production from cocoa pod husks: A review

Cocoa beans are produced through on-farm processing where residual biomass is discarded, including cocoa pod husks (CPH), cocoa bean shells and cocoa sweatings. CPH represents about 80% of these residues that are generated during the initial cocoa bean processing steps and their disposal occupies large areas, causing social and environmental concerns. In the last decades, the lignocellulosic composition of CPH has attracted the attention of the scientific and productive sector. Recently, some studies have reported the use of CPH in the production of medium to high value-added molecules, with potential applications in food and feed, agriculture, bioenergy, and other segments. This review presents biotechnological approaches and processes for the exploitation of CPH, including pre-treatment methods for the production of different biomolecules. Great perspectives and innovations were found concerning CPH exploitation and valorisation, but still more efforts are needed to valorise this potential feedstock and give support to producers in-development countries.

Fungal xylanolytic enzymes: Diversity and applications

As important polysaccharide degraders in nature, fungi can diversify their extensive set of carbohydrate-active enzymes to survive in ecological habitats of various composition. Among these enzymes, xylanolytic ones can efficiently and sustainably degrade xylans into (fermentable) monosaccharides to produce valuable chemicals or fuels from, for example relevant for upgrading agro-food industrial side streams. Moreover, xylanolytic enzymes are being used in various industrial applications beyond biomass saccharification, e.g. food, animal feed, biofuel, pulp and paper. As a reference for researchers working in related areas, this review summarized the current knowledge on substrate specificity of xylanolytic enzymes from different families of the Carbohydrate-Active enZyme database. Additionally, the diversity of enzyme sets in fungi were discussed by comparing the number of genes encoding xylanolytic enzymes in selected fungal genomes. Finally, to support bio-economy, the current applications of fungal xylanolytic enzymes in industry were reviewed.