High value-added products from the orange juice industry waste

Reducing citrus effluent toxicity: Biological-electrochemical treatment with diamond anode

One challenge of the citrus industry is the treatment and disposal of its effluents due to their high toxicity, substantial organic load, and consequent resistance to conventional biotechnological processes. This study introduces a novel approach, using electrochemical oxidation with a boron-doped diamond anode to efficiently remove organic compounds from biodegraded pulp wash (treated using the fungus Pleurotus sajor-caju.) The findings reveal that employing a current density of 20 mA cm-2 achieves notable results, including a 44.1% reduction in color, a 70.0% decrease in chemical oxygen demand, an 88.0% reduction in turbidity, and an impressive 99.7% removal of total organic carbon (TOC) after 6 h of electrolysis. The energy consumption was estimated at 2.93 kWh g-1 of removed TOC. This sequential biological-electrochemical procedure not only significantly reduced the mortality rate (85%) of Danio rerio embryos but also reduced the incidence of morphologically altered parameters. Regarding acute toxicity (LC50) of the residue, the process demonstrated a mortality reduction of 6.97% for D. rerio and a 40.88% lethality decrease for Lactuca sativa seeds. The substantial reduction in toxicity and organic load observed in this study highlights the potential applicability of combined biological and electrochemical treatments for real agroindustrial residues or their effluents.

Hesperidin from Orange Peel as a Promising Skincare Bioactive: An Overview

The pursuit for better skin health, driven by collective and individual perceptions, has led to the demand for sustainable skincare products. Environmental factors and lifestyle choices can accelerate skin aging, causing issues like inflammation, wrinkles, elasticity loss, hyperpigmentation, and dryness. The skincare industry is innovating to meet consumers' requests for cleaner and natural options. Simultaneously, environmental issues concerning waste generation have been leading to sustainable strategies based on the circular economy. A noteworthy solution consists of citrus by-product valorization, as such by-products can be used as a source of bioactive molecules. Citrus processing, particularly, generates substantial waste amounts (around 50% of the whole fruit), causing unprecedented environmental burdens. Hesperidin, a flavonoid abundant in orange peels, is considered to hold immense potential for clean skin health product applications due to its antioxidant, anti-inflammatory, and anticarcinogenic properties. This review explores hesperidin extraction and purification methodologies as well as key skincare application areas: (i) antiaging and skin barrier enhancement, (ii) UV radiation-induced damage, (iii) hyperpigmentation and depigmentation conditions, (iv) wound healing, and (v) skin cancer and other cutaneous diseases. This work's novelty lies in the comprehensive coverage of hesperidin's promising skincare applications while also demonstrating its potential as a sustainable ingredient from a circular economy approach.

Pulsed electric field technology as a promising pre-treatment for enhancing orange agro-industrial waste biorefinery

In the processing of orange juice, 50-70% of the fresh fruit weight is converted into organic waste. Orange processing waste (OPW) primarily consists of peels, seeds, and pulp. Improper disposal of this residue can lead to greenhouse gas emissions, environmental pollution, and the wastage of natural resources. To address this ecological issues, recent research has focused on developing innovative process designs to maximize the valorization of OPW through biorefinery strategies. However, the current challenge in implementing these methods for industrial waste management is their significant energy consumption. In response to these challenges, recent studies have explored the potential of employing pulsed electric field (PEF) technology as a pre-treatment to improve energy efficiency in biorefinery processes. This non-thermal and emerging technology can enhance the mass transfer of intracellular components via electroporation of cell walls, thereby resulting in shorter processing times, lower energy inputs, greater retention of thermosensitive components, and higher extraction yields. In this regard, this review offers a comprehensive discussion on the innovative biorefinery strategies to the valorization of OPW, with a specific focus on recent studies assessing the technical feasibility of methodologies for the extraction of phytochemical compounds, dehydration processes, and bioconversion methods. Recent studies that discussed the potential of PEF technology to reduce energy demand by increasing the mass transfer of biological tissues were emphasized.

Progress on Separation and Hydrothermal Carbonization of Rice Husk Toward Environmental Applications

Owing to the increasing global demand for carbon resources, pressure on finite materials, including petroleum and inorganic resources, is expected to increase in the future. Efficient utilization of waste resources has become crucial for sustainable resource acquisition for creating the next generation of industries. Rice husks, which are abundant worldwide as agricultural waste, are a rich carbon source with a high silica content and have the potential to be an effective raw material for energy-related and environmental purification materials such as battery, catalyst, and adsorbent. Converting these into valuable resources often requires separation and carbonization; however, these processes incur significant energy losses, which may offset the benefits of using biomass resources in the process steps. This review summarizes and discusses the high value of RHs, which are abundant as agricultural waste. Technologies for separating and converting RHs into valuable resources by hydrothermal carbonization are summarized based on the energy efficiency of the process.

The potential of citrus by-products in the development of functional food and active packaging

Food by-product valorization has become an important research area for promoting the sustainability of the food chain. Citrus fruits are among the most widely cultivated fruit crops worldwide. Citrus by-products, including pomace, seeds, and peels (flavedo and albedo), are produced in large amounts each year. Those by-products have an important economic value due to the high content on bioactive compounds, namely phenolic compounds and carotenoids, and are considered a valuable bio-resource for potential applications in the food industry. However, green extraction techniques are required to ensure their sustainability. This chapter addresses the main components of citrus by-products and their recent applications in food products and active food packaging, towards a circular economy. In addition, the concern regarding citrus by-products contamination (e.g. with pesticides residues and mycotoxins) is also discussed.

Fruit residues as biomass for bioethanol production using enzymatic hydrolysis as pretreatment

The commercialization of fruits in markets generates a large amount of waste because they are perishable and have a short shelf life, so, they are discarded. This study aimed to provide a noble end to discarded fruits that have fermentable sugars. Banana, apple, mango and papaya residues were collected from supermarkets and underwent an enzymatic hydrolysis process. The ability of four pectinases, two amylases, one xylanase and one cellulase to release reducing sugars from fruit biomass before fermentation with two yeast strains (S. cerevisiae CAT-1 and S. cerevisiae Angel) for bioethanol production was investigated, obtaining a total of RS (Reducing sugar) of 268.08 mg/mL in banana residues. A fermentation with yeast S. cerevisiae CAT-1 resulted in 98% consumption of RS and the production of a total of 28.02 g/L of ethanol. Furthermore, fermentation with the yeast S. cerevisiae Angel, resulted in 97% RS consumption and 31.87 g/L ethanol production, which was the best result obtained throughout all the tests of hydrolysis, highlighting the banana residue as a promising biomass for the production of bioethanol.

Juices and By-Products of Red-Fleshed Sweet Oranges: Assessment of Bioactive and Nutritional Compounds

The content of nutrients and bioactive compounds, and antioxidant capacity were assessed in the juices from two red-fleshed oranges, Cara Cara and Kirkwood, and compared with that of a standard Navel orange. Two juice extraction procedures, hand-squeezing and industrial, and two treatments, pasteurization (85 °C/30 s) and high-pressure homogenization (HPH, 150 MPa/55 °C/1 min), were evaluated. For most of the nutrients and bioactive compounds, the hand and industrial juice squeezing rendered similar extraction efficiency. Individual composition of carotenoids in the juices were differentially affected by the extraction procedure and the treatments, but the red-fleshed orange juices contained between 3- to 6-times higher total carotenoids than the standard Navel juices, being phytoene and phytofluene the main carotenoids. The industrial and treated juices of both red-fleshed oranges contained 20-30% higher amounts of tocopherols but about 20% lower levels of vitamin C than Navel juices. Navel juices exhibited higher hydrophilic antioxidant capacity, while the red-fleshed orange juices showed an improved lipophilic antioxidant capacity. The main distinctive characteristic of the industrial juice by-product of the red-fleshed oranges was a higher content of carotenoids (×10) and singlet oxygen antioxidant capacity (×1.5-2) than the Navel by-product.

Evaluation of pectin extractions and their application in the alkaline Maillard reaction

A 2³ factorial design was used to evaluate the influence of temperature, catalyst and time and esterification degree (DE) of pectin obtained from mango, orange and tangerine peels as well as tamarind seeds by using the acid hydrolysis method. The study showed that a high temperature positively influenced the percentage of pectin yield for the four second generation biomasses. Nevertheless, the temperature showed a greater influence in the solubility and diffusion of the acid solvent in the tamarind seed matrix, resulting a pectin recovery 32.9%. Concerning the %DE, the most statistically significant value observed was dependent on the type of biomass studied. The %DE and the nature of the pectin are determining factors in the pectin's final use, in the present work the pectin extracted was used to produce furfural, a precursor of high value chemicals. The furfural production was achieved through alkaline hydrolysis and enhanced using the Maillard reaction, reaching a maximum concentration of 71.8 g/L which represents a 42.1% increase from the alkaline hydrolysis.

Fruit Juice Industry Wastes as a Source of Bioactives

Food processing sustainability, as well as waste minimization, are key concerns for the modern food industry. A significant amount of waste is generated by the fruit juice industry each year. In addition to the economic losses caused by the removal of these wastes, its impact on the environment is undeniable. Therefore, researchers have focused on recovering the bioactive components from fruit juice processing, in which a great number of phytochemicals still exist in the agro-industrial wastes, to help minimize the waste burden as well as provide new sources of bioactive compounds, which are believed to be protective agents against certain diseases such as cardiovascular diseases, cancer, and diabetes. Although these wastes contain non-negligible amounts of bioactive compounds, information on the utilization of these byproducts in functional ingredient/food production and their impact on the sensory quality of food products is still scarce. In this regard, this review summarizes the most recent literature on bioactive compounds present in the wastes of apple, citrus fruits, berries, stoned fruits, melons, and tropical fruit juices, together with their extraction techniques and valorization approaches. Besides, on the one hand, examples of different current food applications with the use of these wastes are provided. On the other hand, the challenges with respect to economic, sensory, and safety issues are also discussed.

Modification of Orange Bagasse with Reactive Extrusion to Obtain Cellulose-Based Materials

Orange bagasse (OB) could be considered a sustainable, renewable, and low-cost biomass for the extraction of cellulose. In this context, reactive extrusion can be considered an excellent, eco-friendly, alternative process for the extraction of cellulose from lignocellulosic materials. Thus, the present study aimed to obtain cellulose-based materials with a reactive extrusion process and also to investigate the impact of pectin on the delignification process. Two groups of samples (OB and depectinizated OB) were submitted to extrusion with sulfuric acid or sodium hydroxide in one-step processes. The cellulose content of extruded materials was highly affected by pectin content in the raw material; the thermal profile (TGA curves) and crystallinity also changed. The cellulose content of modified materials ranged from 18.8% to 58.4%, with a process yield of 30.6% to 79.2%. The alkaline reagent provided the highest cellulose content among all extrusion treatments tested, mainly for OB without pectin. The extrusion process was considered an efficient and promising process for extracting cellulose from citrus residue. Materials produced in this study can be used as sources of cellulose fiber for various products and processes, such as in the food industry, fermentation substrates, or refined applications after subsequent treatments.

Integrated biorefinery approach to valorize citrus waste: A sustainable solution for resource recovery and environmental management

Citrus fruits are extensively cultivated, consumed and major processed horticulture crops around the globe. High processing and consumption generate huge quantities of solid organic wastes. Citrus waste represents approximately 40-50% of total fruit weight, which consists of rag (membranes and cores), pulp, seeds, and peel (albedo and flavedo), which are a potential source of value-added products including essential oils, carotenoids, pectin, dietary fibers, and polyphenols biofuel, etc. However, waste produced is discarded as waste in the environment, which causes a serious threat due to the presence of bioactive compounds. Recent research strategies on the integrated biorefinery approach explore various ways to utilize the waste obtained from the citrus wastes for their subsequent recovery of value-added products. Moreover, the citrus waste can be turned into various bio-products, viz., enzymes, biofuels, and biopolymers using the integrated biorefinery approach, which can optimize the development of green waste for sustainability and economic benefits. Given the sustainable solution for resource recovery and environmental management, the article reviews the latest advances in the novel valorization approach and valuation of the existing state-of-the-art green technologies for citrus waste utilization to bring a sustainable solution for increasing demand for food, fuel, and energy security. To achieve the zero-waste approach and industrial viability, more efforts should be given to scale-up green recovery techniques along with diverse product profiling.

Lignocellulosic Biomass Valorization for Bioethanol Production: a Circular Bioeconomy Approach

Lignocellulosic biomass generated from different sectors (agriculture, forestry, industrial) act as biorefinery precursor for production of second-generation (2G) bioethanol and other biochemicals. The integration of various conversion techniques on a single platform under biorefinery approach for production of biofuel and industrially important chemicals from LCB is gaining interest worldwide. The waste generated on utilization of bio-resources is almost negligible or zero in a biorefinery along with reduced greenhouse gas emissions, which supports the circular bioeconomy concept. The economic viability of a lignocellulosic biorefinery depends upon the efficient utilization of three major components of LCB-cellulose, hemicellulose and lignin. The heterogeneous structure and recalcitrant nature of LCB is main obstacle in its valorization into bioethanol and other value-added products. The success of bioconversion process depends upon methods used during pre-treatment, hydrolysis and fermentation processes. The cost involved in each step of the bioconversion process affects the viability of cellulosic ethanol. The lignocellulose biorefinery has ample scope, but much-focused research is required to fully utilize major parts of lignocellulosic biomass with zero wastage. The present review entails lignocellulosic biomass valorization for ethanol production, along with different steps involved in its production. Various value-added products produced from LCB components were also discussed. Recent technological advances and significant challenges in bioethanol production are also highlighted in addition to future perspectives.

Micro- and nanocelluloses from non-wood waste sources; processes and use in industrial applications

In addition to renewability and abundance, nanocellulose materials have tremendous (and variable) properties for different applications, ranging from bulk applications, such as paper and packaging reinforcement, to emerging high added-value applications, such as substrates for optoelectronics. Lignocellulosic biomass from agricultural and industrial waste sources is readily available and shows great promise as an inexpensive and sustainable raw material for nanocellulose production. However, the understanding of the potential of using non-wood based biowaste sources is not established and systematic comparisons of versatile agricultural and industrial waste sources can elucidate this complex topic. Here we present an overview of the most studied and most promising sources from agro-industrial waste, the processes to convert them into nanocellulose, some of the established and emerging applications, and discuss the advancements that are still needed for large-scale production. Sugarcane bagasse and oil palm empty fruit bunch have been the most researched waste-based sources for nanocellulose production and demonstrate the most promise due to availability and access. Industrial sources seem to have advantages over agricultural sources in collectability and ease of access. This work gives insight on the potential and the challenges of nanocellulose production from waste sources and discusses how the criteria set for nanocellulose materials in different applications can be met, thus opening new routes for circular economy.

The Second Life of Citrus Fruit Waste: A Valuable Source of Bioactive Compounds

Citrus fruits (CF) are among the most widely cultivated fruit crops throughout the world and their production is constantly increasing along with consumers' demand. Therefore, huge amounts of waste are annually generated through CF processing, causing high costs for their disposal, as well as environmental and human health damage, if inappropriately performed. According to the most recent indications of an economic, environmental and pharmaceutical nature, CF processing residues must be transformed from a waste to be disposed to a valuable resource to be reused. Based on a circular economy model, CF residues (i.e., seeds, exhausted peel, pressed pulp, secondary juice and leaves) have increasingly been re-evaluated to also obtain, but not limited to, valuable compounds to be employed in the food, packaging, cosmetic and pharmaceutical industries. However, the use of CF by-products is still limited because of their underestimated nutritional and economic value, hence more awareness and knowledge are needed to overcome traditional approaches for their disposal. This review summarizes recent evidence on the pharmacological potential of CF waste to support the switch towards a more environmentally sustainable society.

The Food-Materials Nexus: Next Generation Bioplastics and Advanced Materials from Agri-Food Residues

The most recent strategies available for upcycling agri-food losses and waste (FLW) into functional bioplastics and advanced materials are reviewed and the valorization of food residuals are put in perspective, adding to the water-food-energy nexus. Low value or underutilized biomass, biocolloids, water-soluble biopolymers, polymerizable monomers, and nutrients are introduced as feasible building blocks for biotechnological conversion into bioplastics. The latter are demonstrated for their incorporation in multifunctional packaging, biomedical devices, sensors, actuators, and energy conversion and storage devices, contributing to the valorization efforts within the future circular bioeconomy. Strategies are introduced to effectively synthesize, deconstruct and reassemble or engineer FLW-derived monomeric, polymeric, and colloidal building blocks. Multifunctional bioplastics are introduced considering the structural, chemical, physical as well as the accessibility of FLW precursors. Processing techniques are analyzed within the fields of polymer chemistry and physics. The prospects of FLW streams and biomass surplus, considering their availability, interactions with water and thermal stability, are critically discussed in a near-future scenario that is expected to lead to next-generation bioplastics and advanced materials.

Nanocelluloses: Sources, Pretreatment, Isolations, Modification, and Its Application as the Drug Carriers

The 'Back-to-nature' concept has currently been adopted intensively in various industries, especially the pharmaceutical industry. In the past few decades, the overuse of synthetic chemicals has caused severe damage to the environment and ecosystem. One class of natural materials developed to substitute artificial chemicals in the pharmaceutical industries is the natural polymers, including cellulose and its derivatives. The development of nanocelluloses as nanocarriers in drug delivery systems has reached an advanced stage. Cellulose nanofiber (CNF), nanocrystal cellulose (NCC), and bacterial nanocellulose (BC) are the most common nanocellulose used as nanocarriers in drug delivery systems. Modification and functionalization using various processes and chemicals have been carried out to increase the adsorption and drug delivery performance of nanocellulose. Nanocellulose may be attached to the drug by physical interaction or chemical functionalization for covalent drug binding. Current development of nanocarrier formulations such as surfactant nanocellulose, ultra-lightweight porous materials, hydrogel, polyelectrolytes, and inorganic hybridizations has advanced to enable the construction of stimuli-responsive and specific recognition characteristics. Thus, an opportunity has emerged to develop a new generation of nanocellulose-based carriers that can modulate the drug conveyance for diverse drug characteristics. This review provides insights into selecting appropriate nanocellulose-based hybrid materials and the available modification routes to achieve satisfactory carrier performance and briefly discusses the essential criteria to achieve high-quality nanocellulose.

Encapsulation and delivery of bioactive citrus pomace polyphenols: a review

Citrus pomace consists of the peel, pulp, and membrane tissues remaining after juice expression. Globally, around one million tons of citrus pomace are generated annually, which contains a variety of bioactive constituents that could be used as value-added functional ingredients in foods. However, the polyphenols in citrus pomace are not currently being utilized to their full potential, even though they can be used as nutraceuticals in functional foods and beverages. Citrus phenolics face significant roadblocks to their successful incorporation into these products. In particular, they have poor water solubility, chemical stability, and bioavailability. This review describes the diverse range of colloidal systems that have been developed to encapsulate and deliver citrus phenolics. Examples of the application of these systems for the encapsulation, protection, and delivery of polyphenols from citrus pomace are given. The use of colloidal delivery systems has been shown to improve the stability, dispersibility, and bioaccessibility of encapsulated polyphenols from citrus pomace. The selection of an appropriate delivery system determines the handling, storage, shelf life, encapsulation efficiency, dispersibility, and gastrointestinal fate of the citrus polyphenols. Furthermore, the purity, solubility, and chemical structure of the polyphenols are key factors in delivery system selection.

Valorization of orange bagasse through one-step physical and chemical combined processes to obtain a cellulose-rich material

BACKGROUND

Orange bagasse (OB) is an agroindustrial residue of great economic importance that has been little explored for the extraction of cellulose. The present study aimed to investigate different combinations of chemical (sodium hydroxide, peracetic acid and alkaline peroxide) and physical (autoclaving and ultrasonication) treatments performed in one-step processes for cellulose extraction from OB and to characterize the materials obtained according to their composition, morphology, crystallinity and thermal stability.

RESULTS

The processing yields ranged from 140 to 820 g kg^-1 , with a recovery of 720-1000 g kg^-1 of the original cellulose. Treatments promoted morphological changes in the fiber structure, resulting in materials with higher porosity, indicating partial removal of the noncellulosic fractions. The use of combined chemical treatments (NaOH and peracetic acid) with autoclaving was more efficient for obtaining samples with the highest cellulose contents.

CONCLUSION

Therefore, AC_SH (processed by autoclaving with NaOH) was the most effective one-step treatment, resulting in 71.1% cellulose, 0% hemicellulose and 19.0% lignin, with a crystallinity index of 42%. The one-step treatments were able to obtain materials with higher cellulose contents and yields, reducing reaction times and the quantity of chemical reagents employed in the overall processes compared to multistep conventional processes. © 2020 Society of Chemical Industry.

Recent advances in the biological valorization of citrus peel waste into fuels and chemicals

In the quest to reduce global food loss and waste, fruit processing wastes, particularly citrus peel waste (CPW), have emerged as a promising and sustainable option for biorefinery without competing with human foods and animal feeds. CPW is largely produced and, as recent studies suggest, has the industrial potential of biological valorization into fuels and chemicals. In this review, the promising aspects of CPW as an alternative biomass were highlighted, focusing on its low lignin content. In addition, specific technical difficulties in fermenting CPW are described, highlighting that citrus peel is high in pectin that consist of non-fermentable sugars, mainly galacturonic acid. Last, recent advances in the metabolic engineering of yeast and other microbial strains that ferment CPW-derived sugars to produce value-added products, such as ethanol and mucic acid, are summarized. For industrially viable CPW-based biorefinery, more studies are needed to improve fermentation efficiency and to diversify product profiles.

Nanocellulose from various biomass wastes: Its preparation and potential usages towards the high value-added products

Biomass waste comes from a wide range of sources, such as forest, agricultural, algae wastes, as well as other relevant industrial by-products. It is an important alternative energy source as well as a unique source for various bioproducts applied in many fields. For the past two decades, how to reuse, recycle and best recover various biomass wastes for high value-added bioproducts has received significant attention, which has not only come from various academia communities but also from many civil and medical industries. To summarize one of the cutting-edge technologies applied with nanocellulose biomaterials, this review focused on various preparation methods and strategies to make nanocellulose from diverse biomass wastes and their potential applications in biomedical areas and other promising new fields.

New Sustainable Process for Hesperidin Isolation and Anti-Ageing Effects of Hesperidin Nanocrystals

Hesperidin, a secondary orange (Citrus sinensis) metabolite, was extracted from orange bagasse. No organic solvents or additional energy consumption were used in the clean and sustainable process. Hesperidin purity was approximately 98% and had a yield of 1%. Hesperidin is a known supplement due to antioxidant, chelating, and anti-ageing properties. Herein, hesperidin application to eliminate dark eye circles, which are sensitive and thin skin regions, was studied. In addition, the proposed method for its aqueous extraction was especially important for human consumption. Further, the most effective methods for hesperidin nanonization were explored, after which the nanoemulsions were incorporated into a cream formulation that was formulated for a tropical climate. Silky cream formulations (oil in water) were tested in vitro on artificial 3D skin from cultured cells extracted from skin residues after plastic surgery. The proposed in vitro assay avoided tests of the different formulations in human volunteers and animals. It was shown that one of the nanonized hesperidin formulations was the most skin-friendly and might be used in cosmetics.

Nanocellulose Production: Exploring the Enzymatic Route and Residues of Pulp and Paper Industry

Increasing environmental and sustainability concerns, caused by current population growth, has promoted a raising utilization of renewable bio-resources for the production of materials and energy. Recently, nanocellulose (NC) has been receiving great attention due to its many attractive features such as non-toxic nature, biocompatibility, and biodegradability, associated with its mechanical properties and those related to its nanoscale, emerging as a promising material in many sectors, namely packaging, regenerative medicine, and electronics, among others. Nanofibers and nanocrystals, derived from cellulose sources, have been mainly produced by mechanical and chemical treatments; however, the use of cellulases to obtain NC attracted much attention due to their environmentally friendly character. This review presents an overview of general concepts in NC production. Especial emphasis is given to enzymatic hydrolysis processes using cellulases and the utilization of pulp and paper industry residues. Integrated process for the production of NC and other high-value products through enzymatic hydrolysis is also approached. Major challenges found in this context are discussed along with its properties, potential application, and future perspectives of the use of enzymatic hydrolysis as a pretreatment in the scale-up of NC production.

Pulp wash: a new source for production of ligninolytic enzymes and biomass and its toxicological evaluation after biological treatment

Pulp wash was used as substrate for the activity of ligninolytic enzymes of the fungus Pleurotus sajor-caju. Activity of laccase (Lac) and manganese peroxidase (MnP) as well as fungal biomass occurred under four conditions: different pulp wash concentrations, pH variation at the optimal pulp wash concentration, different glucose concentrations, and different concentrations of ammonium nitrate. The best enzyme activity and biomass production were obtained with in natura pulp wash and pH corrected to 5.0 (4884 IU/L Lac; 82 IU/L MnP; 25 g/100 mL biomass). However, the addition of glucose and ammonium nitrate to the pulp wash was not necessary for increasing the enzyme activity and biomass production. Efficient removal of pulp wash chemical oxygen demand (99.66%) and biochemical oxygen demand (83.27%) occurred after the mycoremediation with P. sajor-caju in the optimized conditions. Lactuca sativa L. seeds germination bioassay showed a four-fold reduction in the residue toxicity (EC₅₀ 28.72%) after the treatment with the fungus. Our findings are consistent with the notion that pulp wash is an excellent substrate for inducing the activity of ligninolytic enzymes and producing fungal biomass, and that the biological treatment is efficient to reduce effluent toxicity.

Chemical characterization, antioxidant, cytotoxicity, Anti-Toxoplasma gondii and antimicrobial potentials of the Citrus sinensis seed oil for sustainable cosmeceutical production

There are growing concerns about the chronic and acute effects of synthetic additives such as antibacterial, fragrances, colourants and stabilizing agents used in the production of various household products. Many household products and materials including cosmetic products are reportedly suspected to be carcinogenic with some acting as endocrine disruptors among other effects. Thus, environmental-friendly alternatives such as products that are rich in bioactive phytochemicals are becoming consumers' preferred choice especially in the beauty and cosmetic sector. 'Green' preparation of medicinal soaps devoid of any synthetic additives was made from underutilized tropical seed of Citrus sinensis seed oil and some natural additives comprising of natural honey, Ocimum gratissimum leaves extract, Moringa oleifera seed oil and coconut oil. Precisely, the seed oil of the underexplored C. sinensis was obtained via soxhlet extraction and saponified with natural lye solution at different ratios to produce soaps of varying characteristics. The incorporation of honey and Ocimum gratissimum leaf extract provided additional antimicrobial, antioxidant and fragrance properties. Physico-chemical parameters of the oil and soaps were determined following standard procedures while the fatty acid profile of the trans-esterified oil was determined using GC-MS. The antimicrobial potential of the oil and soaps were assessed using agar diffusion method at concentrations 200 mg/mL and below. Linoleic acid (36%) and oleic acid (27%) were the most prominent in C. sinensis seed oil. The soap had antimicrobial potential comparable to commercial product. The soap samples recorded highest anti-bacteria activities (22.0 ± 1.0-23.0 ± 1.0) against Staphylococcus aureus and Bacillus subtilis and notable anti-fungi activities (18.0 ± 1.0) against Penicillium notatum and Candida albicans. Additionally, the oil showed moderate anti-parasite (anit-toxoplasma gondii) activity (EC50 ≤ 500 μg/mL) but with improved selectivity that precludes oxidative stress while the prepared medicinal soaps exhibited remarkable antioxidant property. The utilization of these locally sourced resources will prevent the daily introduction of synthetic antimicrobial and antioxidant chemicals into the environment. The initiative avail a sustainable production of environmentally-benign cosmetic products besides conversion of waste to wealth agrees which aligns with the Sustainable Development Goals (SDGs).

Lignocellulosic nanofibrils produced using wheat straw and their pulping solid residue: From agricultural waste to cellulose nanomaterials

Each year millions of tons of agricultural wastes are produced, however, not well utilized in China. Considering the economic development and environmental protection, the valorization of these wastes is increasingly necessary and important. Here we used p-toluenesulfonic acid hydrolysis followed by mild disk grinding for on-farm valorization of wheat straw (WS) and their pulping solid residue (waste wheat straw, WWS) to produce lignocellulosic nanofibrils (LCNF). Alkaline peroxide post-treatment was further conducted to obtain purified lignocellulosic nanofibrils (P-LCNF) with lower lignin content and thinner diameters. The raw materials and resulting LCNF and P-LCNF were investigated in each process for their chemical component, crystal structure, morphology, and thermal properties. Interestingly, although WS fiber had higher lignin content than WWS fiber, the WS fiber with lower ash content resulted in LCNF and P-LCNF with smaller height and lower thermal stability, but higher crystallinity and higher specific surface area. Higher ash content in WWS fiber protected cellulose and lignin from depolymerization and degradation, respectively, which endowed LCNF and P-LCNF with entangled network structure. Overall, this study indicated that the low-temperature fractionation process on WS and WWS fibers could yield cellulose nanomaterials with potential value-added application and achieve the efficient utilization of agricultural wastes.

Thermal degradation behavior of pectin in citrus wastes with density functional theory study

Citrus wastes contain large amounts of pectin as the main constituent in addition to cellulose, lignin and hemicellulose. The thermal degradation behaviors and products distribution from the fast pyrolysis of citrus wastes are different from lignocellulosic biomass due to the high content of pectin. In view of this, the detailed decomposition behaviors of pectin are investigated by using density functional theory (DFT). The calculation results indicate that the most energetically favored initial reaction of pectin is the cleavage of α-1,4-glycoside bond (C₁O bond) with an energy barrier of 126.4 kJ/mol. In addition, compared with the reaction energy barriers, it can be seen that the formation of CO, CH₄ and furan are more difficult than that of CO₂, methanol and furfural, respectively. The comprehensive kinetic analysis indicates that Path-A₂-2 should be the most favorable pathway for the formation of acetaldehyde. The rate-determining steps of the formation of furan and furfural are dehydration reactions while decarbonylation reaction is the result of the rate-determining step of the formation of methyl 2-furoate and propanone.

Biocatalyst Potential of Cellulose-Degrading Microorganisms Isolated from Orange Juice Processing Waste

Cellulases can be applied as macerating and peeling enzymes in the orange juice processing industry. In this work, indigenous cellulose-degrading microorganisms were isolated from orange juice processing waste through successive enrichment procedures using carboxymethyl cellulose (CMC) as the sole carbon source. A total of 24 microbial isolates were screened for their ability to grow in CMC liquid medium, resulting in the selection of seven isolates. The latter were further assessed by determining their endo-1,4-β-d-glucanase, exo-1,4-β-d-glucanase, and β-1,4-d-glucosidase activities, of which their respective activities were as high as 3.89, 10.67, and 10.69 U/mg protein. All cellulose-degraders selected belonged to the genus Paenibacillus, although to distinct operational taxonomic units related to P. xylanexedens, P. tundrae, and P. pabuli (operational taxonomic unit—OTU#1) and to P. wynnii, P. odorifer, and P. donghaensis (OTU#2) spectrum. Regarding the cellulase activities of the orange juice processing waste, endo-1,4-β-d-glucanase activity (4.00 ± 0.11 U/g) was exerted only extracellularly, whereas exo-1,4-β-d-glucanase (2.60 ± 0.19 U/g) and β-1,4-d-glucosidase (5.69 ± 0.23 U/g) activities were exhibited both extracellularly and intracellularly. In conclusion, orange juice processing waste can be considered as a valuable source for the isolation of cellulose-degrading microbiota with potential uses in beverage industry, solid state fermentation and energy production.