Agro-industrial Residues Research Articles

Assessment of Parameters to Apply Osmotic Dehydration as Pretreatment for Improving the Efficiency of Convective Drying of Cassava Bagasse

This manuscript corresponds to exploratory research carried out to evaluate and define the operating parameters for applying osmotic dehydration (OD) as pretreatment for efficiency improvement in the convective drying of cassava bagasse, providing a methodology to apply these combined techniques, not only for cassava bagasse but also to serve as a reference for its use in other high-moisture agro-industrial residues. Operating factors significant for moisture loss during OD were determined through sieving analysis. Adequate levels and operating conditions were determined for OD and subsequent drying (osmotic agent concentration, solution-to-sample ratio, agitation speed, immersion time, required draining mesh, draining time, drying temperature, and drying air speed). It was established that an osmotic treatment was able to reduce the moisture of cassava bagasse from 87.7% to 28.94% and subsequent drying time by approximately 38.8%. These results allow the use of these combined techniques for drying cassava bagasse, which in turn, open a research agenda for its application in other agro-industrial residues, contributing to its handling, revaluation, and development of a sustainable agro-industry.

Chemical, Technological, and Sensory Quality of Pasta and Bakery Products Made with the Addition of Grape Pomace Flour.

Grapes are one of the most cultivated fruits in the world. Concomitantly, a large amount of waste is generated from this product. Grape pomace (GP) flour can be used as an increment for making new food products. GP is rich in fibers and phenolic compounds, and in addition could be used to reduce agro-industrial residues. Thus, the objective of this study was to evaluate the influence of the addition of different percentages of grape pomace (GP) on the chemical, technological, and sensory characteristics in pasta and bakery products. An integrative review was conducted. The selection of papers was carried out by searching studies in databases. An improvement in chemical quality with the addition of GP was observed, such as fiber, anthocyanin, and micronutrient content. Biscuits, cookies, cakes, breads, and pasta did not show any impairment in terms of acceptability. However, biscuits and cookies had the best global acceptance. The degree of acceptance still seems to be low for the use of GP to be included in high quantities in successful products. Samples with a maximum of 10% addition of GP flour seem to be accepted. On the other hand, the higher the percentage of GP flour, the healthier benefits they seem to promote.

Production of the Food Enzyme Acetolactate Decarboxylase (ALDC) from Bacillus subtilis ICA 56 Using Agro-Industrial Residues as Feedstock

During the beer brewing process, some compounds are formed in the primary fermentation step and may affect the final quality of beer. These compounds, called off flavors, such as diacetyl, are produced during fermentation and are related to a buttery taste. The use of acetolactate decarboxylase (ALDC) in the traditional beer brewing process may significantly increase productivity since it allows for a faster decrease in the adverse flavor caused by diacetyl. However, production costs directly impact its application. For this reason, we analyzed the effect of different cultivation media on ALDC production by Bacillus subtilis ICA 56 and process economics. Different carbon and nitrogen sources, including agro-industrial residues, were evaluated. The best result was obtained using sugarcane molasses and corn steep solids (CSS), allowing a 74% reduction in ALDC production cost and an enzyme activity of 4.43 ± 0.12 U·mL−1. The enzymatic extract was then characterized, showing an optimum temperature at 40 °C and stability at different pH levels, being able to maintain more than 80% of its catalytic capacity between pH values of 3.6 and 7.0, with higher enzymatic activity at pH 6.0 (50 mM MES Buffer), reaching an ALDC activity of 5.30 ± 0.06 U·mL−1.

Effect of metals on mesophilic anaerobic digestion of strawberry extrudate in batch mode

According to recent studies, the anaerobic digestion of strawberry extrudate is a promising option with potential in the berry industry biorefinery. However, the lack and/or unbalance of concentrations of metals in some agro-industrial residues could hamper methane production during the anaerobic digestion of these kinds of wastes. In this study, a fractional factorial design was applied to screen the supplementation requirements regarding six metals (Co, Ni, Fe, Cu, Mn, and Zn) for methane production from strawberry extrudate (SE). The logistic model was used to fit the experimental data of methane production-time. It allowed identifying two different stages in the anaerobic process and obtaining the kinetic parameters for each step. Maximum methane production obtained in the first (Bmax) kinetic stage, the methane production in the second stage (P), and the maximum methane production rates (Rmax) concluded a statistically significant effect for Ni and Zn. The second set of experiments was carried out with Ni and Zn through a central composite design to study the concentration effect in the anaerobic digestion process of the strawberry extrudate. The parameters P and Rmax demonstrated a positive interaction between Ni and Zn. Although, Bmax did not prove a statistically significant effect between Ni and Zn.

Opportunities and Challenges from Symbiosis of Agro-Industrial Residue Anaerobic Digestion with Microalgae Cultivation

During the last few years, many studies have tested microalgal systems for nitrogen removal from the digestate. However, most of these studies were carried out using pure culture microalgal strains, which require aseptic conditions and thus cannot be used in full-scale applications. The aim of the present study was to explore opportunities in and challenges of the industrial symbiosis of anaerobic digestion and microalgae cultivation to enhance agro-industrial residue management. Batch tests were carried out to investigate the use of a mixed (open) microalgal consortium to treat the liquid fraction of the digestate for nitrogen removal. Preliminary experiments were performed to choose the carbon supply condition optimizing the growth of the open mixed consortium. In detail, the investigated carbon sources were bicarbonate, under two different carbon to nitrogen ratios, CO2 via the free surface and CO2 via air flushing. Further tests were conducted to compare the use of ammoniacal and nitric nitrogen sources. Then, the effectiveness of the liquid fraction of the digestate as nitrogen source was assessed. The highest biomass concentration of 1.6 g L−1 was obtained using CO2 as carbon source via air flushing as feeding strategy and ammoniacal nitrogen. Biomass production was lower (0.6 g L−1) under the digestate. Nonetheless, due to a probable symbiosis between microalgae and bacteria, a total nitrogen removal of 98.5% was achieved, which was the highest obtained in the present study. Such experimental results address the identification of the steps needed for larger-scale application of combined anaerobic digestion and mixed microalgal systems.

Optimization of low-cost solid-state fermentation media for the production of thermostable lipases using agro-industrial residues as substrate in culture of Bacillus amyloliquefaciens

Herein, we describe an optimized protocol of low-cost solid-state fermentation media for the production of thermostable lipases in culture of Bacillus amyloliquefaciens. The bacteria isolated from environmental samples was tested for lipase production. Lipase production media was optimized with cheap agro-industrial wastes and investigated for enhanced production of lipases by the identified strain in solid-state fermentation. The obtained enzymes were subjected to different physiochemical parameters for their stability checking. Morphological, biochemical and genetic studies shows that the bacterium is gram positive, rod shape Bacillus amyloliquefaciens. Lipase production was observed as 36 U/mL and 35.97 U/mL in media containing 1% fructose and 1% sucrose respectively. The best nitrogen sourced was determined as yeast extract (40 U/mL), peptone (39.90 U/mL), NH4NO3 (30.43 U/mL) at I mM Mg+2, Mn+2, Ca+2 and K+. The inoculum size was optimized as 3–5 % at an incubation time of 72 hrs that yield 80.63 U/mL lipases at an incubation temperature 40 °C and media pH as 7.0. The best results were obtained with agro-industrial waste with optimum enzyme production as 41.20 U/mL in soya bean extract, 25.87 U/ml in rice bran, 25.83 U/mL in wheat bran, 30.03 U/mL (sunflower) and 32.23 U/mL in oat bran. It is concluded that agriculture wastes are the cheapest sources of substrates for the production of low cost lipase enzyme with commercial applications.

A Review on the Applications of Coffee Waste Derived from Primary Processing: Strategies for Revalorization

Coffee is an extremely popular beverage worldwide. To obtain it, the berry must be depulped, fermented, washed, dried, and roasted, producing residues: pulp and husk, mucilage, and parchment. Recently there has been an interest in generating high-value products. In this article, advances in the valorization process are critically reviewed, including an overview of the composition of residues derived from primary processing, uses in food, biocomposite, and biofuel production (thermochemical conversion). With an increasing production of coffee projected in the coming years, there is an urgent need to balance it with the appropriate use and industrial application of coffee wastes and by-products, which are renewable resources rich in carbohydrates, proteins, pectin, and bioactive compounds (polyphenols). The applications described above, together with those that will undoubtedly be developed in the future, represent promising opportunities to take advantage of agro-industrial residues derived from primary processing of Coffea spp. and develop more efficient and sustainable systems through biorefinery approaches and the circular economy.

Biotechnological Conversions of Mizithra Second Cheese Whey by Wild-Type Non-Conventional Yeast Strains: Production of Yeast Cell Biomass, Single-Cell Oil and Polysaccharides

The cultivation of oleaginous yeasts on various agro-industrial residues and the subsequent production of microbial lipids (single-cell oils), which can be used as starting materials for the synthesis of both “second generation” biodiesel and various types of oleochemicals, is considered as one of the most important approaches of the Industrial Biotechnology, in terms of circular economy and green and sustainable development. In this study, seven wild-type non-conventional yeast strains were evaluated for their growth on a semi-defined medium with cheese whey lactose as a sole carbon source. Five of these strains were further batch-cultivated into the complex substrate that contained second cheese whey, which is the main by-product of Mizithra whey cheese manufacture, after centrifugation and filtration without any extra mineral salts, carbon, or nitrogen source addition. All these five strains grown in second cheese whey produced mainly yeast biomass and to lesser extent microbial lipids and other interesting metabolites, such as polysaccharides. The strain Cryptococcus curvatus ATCC 20509 produced the highest total dry weight (TDW) amount (22.4 g/L), that contained 3.4 g/L of intra-cellular lipids, followed by C. curvatus NRRL Y-1511, which produced 20.6 g/L of TDW and 3.2 g/L lipids. A novel, non-previously systematically studied strain, namely Papiliotrema laurentii NRRL Y-2536, produced significant quantities of TDW (22.0 g/L) and, interestingly, secreted quantities of exopolysaccharides. Fed-batch shake-flask cultivation of C. curvatus ATCC 20509 in pretreated second cheese whey, pulse-supplemented with condensed cheese whey-derived lactose, led to the significant TDW quantity of 38.1 g/L that contained c. 57% w/w of total lipids (lipids at a concentration 21.7 g/L were produced). Cellular lipids of all microorganisms, mainly stored as triacylglycerols, contained in variable quantities the fatty acids Δ9C18:1, C16:0, Δ9,12C18:2 and C18:0, constituting perfect candidates for the synthesis of “second generation” biodiesel.

Valorization of Agro-Industrial Wastes and Residues through the Production of Bioactive Compounds by Macrofungi in Liquid State Cultures: Growing Circular Economy

Vast quantities of side streams produced worldwide by the agricultural and food industry present an environmental challenge and an opportunity for waste upcycling in the frame of the circular bioeconomy. Fungi are capable of transforming lignocellulosic residues and wastes into a variety of added-value compounds with applications in functional food products, pharmaceuticals, chemicals, enzymes, proteins, and the emerging sector of nutraceuticals. The liquid state culture of fungi is an efficient and potentially scalable and reproducible biotechnological tool that allows the optimized production of fungal metabolites. Particularly, the utilization of agro-industrial by-products, residues, and wastes as a substrate for the liquid culture of macrofungi is suggested as an attainable solution in the management of these streams, contributing to climate change mitigation. This review presents recently published literature in the field of liquid state cultures of macrofungi using agro-industrial side streams, the different substrates, methods, and factors affecting their growth and metabolite production, as well as their applications, focusing on the variety of natural valuable compounds produced.

Durability Evaluation of New Composite Materials for the Construction of Beehives

Given the current situation we face regarding climate change, one of the greatest and most critical concerns is related to the reduction in the bee population. This population largely depends on beekeeping production units around the world. However, these production units also face great challenges in the construction of beehives, as pine word generally deteriorates within a period of five years or less. This relatively rapid deterioration has both economic and environmental repercussions, which may affect the economic sustainability of the beekeeping system. The objective of this research was the production and subsequent evaluation of the durability of alternative composite materials that can be used in beehive construction. The materials are based on high-density polyethylene and agro-industrial residues (fique fiber, banana fiber, and goose feathers) from the Boyacá region of Colombia. The composite materials studied in the present study were exposed to xylophagous fungi for 90 days, at constant humidity and under controlled temperature conditions that are conducive to fungi proliferation. The results showed that composite materials that include fique fibers are the most promising substitute for wood in the construction of beehives. Indeed, these materials were shown to be 80% more resistant to pathogen attack and durable weight loss than pine wood. These durability results may be of great importance for future implementation in beekeeping production units. They have the potential to impact not only the sustainable development of rural communities, but also to make a great ecological contribution by reducing the need to cut down trees while maintaining the health of beehives.

Transforming second-generation ethanol production waste into sustainable enzymatic cosmetic inputs

Agro-industrial residues were used as a successful, cheap and renewable substrate, capable of increasing activity of ligninolytic enzymes for further use in melanin degradation assays to develop inputs for the treatment of skin hyperpigmentation. The analysis of melanin degradation was performed in a quantitative and qualitative way. The enzymatic crude broth extract, rich in laccases , produced by Marasmiellus palmivorus VE111 in medium formulated with lignocellulosic residues of Araucaria angustifolia subjected to hydrolysis and alcoholic fermentation , degraded almost 33% of the melanin content and enzymatic crude broth extract produced by Pycnoporus sanguineus PR_32 degraded 13%, in just 8 h, using vanillin as a mediator. Proton 2D NMR spectra show melanin changes after laccase treatment. This work has provided an insight for the development of ecofriendly, sustainable and innovative cosmetics to deal with skin hyperpigmentation. • By-products from 2nd generation ethanol production act as inducer to laccases activity. • Vanillin can be used as a safe redox mediator for laccase activity in cosmetics. • Laccase from Marasmiellus palmivorus VE111 can degrade melanin. • HSQC 2D NMR data shows changes in melanin after enzymatic treatment.

Evaluation of agro-industrial residue functionalized with iron oxide magnetic nanoparticles for chloroquine removal from contaminated water

The COVID-19 pandemic has resulted in an increase in wastewater pollution, due to disposal of metabolites of several drugs (e.g., chloroquine (CQN)). Conventional wastewater treatment is not sufficient to remove these contaminants, posing a threat to the aquatic ecosystem and human health. Thus, soybean hulls residues were functionalized with iron oxide nanoparticles (SBH-Fe3O4) and applied in adsorption processes to remove CQN, for the first time. The functionalization was confirmed through material characterization. The results indicated an equilibrium time of 120 min and a maximum adsorption capacity of 98.84 mg g−1 (318 K). The pseudo-first-order and Langmuir models were better fitted to the kinetic and isothermal parameters, respectively. The reuse of the biosorbent was effective for five cycles. Therefore, SBH-Fe3O4 has a high potential for applicability in the treatment of water contaminated by CQN.

Adsorption of Phenylalanine from Aqueous Solutions Using Activated Carbon from Sunflower Meal Functionalized with Sulfonic Groups.

The present work proposes the use of an agro-industrial residue from the sunflower crop as a feedstock to produce a low-cost adsorbent with a chemically modified surface bearing sulfonic groups. This modified low-cost adsorbent can be used for the removal of phenylalanine, and can also be applied in the process of obtaining a source of protein supplementation for patients with phenylketonuria. The functionalization of the adsorbent with sulfonic groups was adapted and presented advantages in terms of execution time, energy expenditure, number of reagents used and adsorbed amino acids. The produced adsorbent presented a surface area of 317.31 m2 g-1 with a predominance of micro- and mesopores, that influenced an approximate 30-fold reduction in adsorption equilibrium time. The optimization results indicated a higher adsorption capacity (39.64 mg g-1) in pH = 4; temperature of 25 °C and adsorbent dosage of 10 g L-1. The FTIR analyzes and the qualitative analysis of the elements present in the samples by EDS confirmed the introduction of sulfonic groups in the MPS500 coal. This work contributed to the understanding behind the adsorption of L-phenylalanine on charcoal surfaces functionalized with sulfonic groups, showing that they can be more selective for the adsorption of phenylalanine in a competitive system.

Biochars from agro-industrial residues of the Amazon: an ecological alternative to enhance the use of phosphorus in agriculture

Biochars from agro-industrial residues of the Amazon: an ecological alternative to enhance the use of phosphorus in agriculture

Mathematical modeling of the biotechnological production of xylitol from hydrolysates of agro-industrial waste

Xylitol is widely used in the pharmaceutical and food industries since it has cariogenic properties and low caloric value compared to sucrose. In recent decades, its demand has increased, which has motivated the generation of alternatives for its production. The biotechnological route is an attractive alternative since in addition to reducing production costs, it uses lignocellulosic hydrolysates from agro-industrial residues as raw material. However, due to the inherent variability in the composition of the waste, the implementation of the process is not a simple task, i. e., the determination of the operating conditions that maximize production yield requires a broad experimental design. In this sense, mathematical modeling can help reduce experimental work, and allows for predicting and evaluating the dynamic behavior of key variables, making it a useful tool for the implementation of process optimization and control schemes. Therefore, the objective of this work is to propose a generalized mathematical model that can be adapted to different study cases (i.e., different substrates and microorganism strains), operating conditions, and fermenter configuration. The results show high determination coefficients R2 > 0.90 for each case study, indicating that the proposed model is easily adaptable to different substrates and operating conditions. In addition, the model allows the incorporation of different effects such as pH, temperature, and agitation.

Utilization of Agro-Industrial Residues in the Rearing and Nutritional Enrichment of Zophobas atratus Larvae: New Food Raw Materials.

Edible insects are a potential alternative food source of high feed conversion efficiency and protein content. Zophobas atratus is an edible insect that adapts to different diets, enabling sustainable rearing by adding value to by-products and agro-industrial residues. This study aimed to evaluate the performance and nutritional characterization of Zophobas atratus larvae fed with different proportions of grape residue. Physicochemical analysis of the diets and larvae (AOAC procedures), fatty acid profile (chromatographic techniques), metals and non-metals (inductively coupled plasma optical emission spectrometry), larval mass gain, feed conversion efficiency, and mortality rate were assessed. The replacement of 25% of the conventional diet with grape residue increased lipid, ash, and fiber contents and reduced protein, carbohydrates, and energy. It promoted greater mass gain, lower mortality rate, and reduced larval growth time by 51%. Among the replacements, 25% resulted in the second-highest content of calcium, sodium, magnesium, and zinc, and the lowest content of potassium and phosphorus in the larvae. The 100% replacement resulted in the highest amounts of C18:2n6 (27.8%), C18:3n3 (2.2%), and PUFA (30.0%). Replacing 25% of the conventional diet with grape residue is equivalent to the conventional diet in many aspects and improves several larvae performance indices and nutritional values.

Deep Eutectic Solvents as a Green Tool for the Extraction of Bioactive Phenolic Compounds from Avocado Peels.

Avocado peels are the main agro-industrial residue generated during the avocado processing, being a rich source of bioactive compounds like phenolic compounds. The growing demand for more sustainable processes requires the development of new and effective methods for extracting bioactive compounds from industrial waste. Deep eutectic solvents (DESs) are a new sustainable alternative to toxic organic solvents due to their non-toxicity and biocompatibility. In this study, five selected DESs were applied for the extraction of bioactive phenolic compounds from avocado peels. The extraction efficiency was evaluated by measuring the total phenolics and flavonoids content. The best extraction results were obtained with choline chloride-acetic acid and -lactic acid (92.03 ± 2.11 mg GAE/g DAP in TPC and 186.01 ± 3.27 mg RE/g DAP); however, all tested DESs show better extraction efficiency than ethanol. All the obtained NADES extracts have high antioxidant activity (FRAP: 72.5–121.1 mg TE/g; TAC: 90.0–126.1 mg AAE/g). The synthesized DESs and avocado peels DES extracts had activity against all tested bacteria (Staphylococcus aureus, Streptococcus dysgalactiae, Escherichia coli and Pseudomonas putida), and the extracts prepared with choline chloride-acetic acid and -lactic acid have the highest antibacterial activity against all microorganisms. These results, coupled with the non-toxic, biodegradable, low-cost, and environmentally friendly characteristics of DESs, provide strong evidence that DESs represent an effective alternative to organic solvents for the recovery of phenolic bioactive compounds from agro-industrial wastes.

Agro-industrial residues as biosorbents for the removal of anti-inflammatories from aqueous matrices: An overview

• First review of biosorbents for pharmaceutical removal; • Focusing on the anti-inflammatory class of pharmaceutical compounds; • Overview considering residue processing and its performance; • Evaluation of adsorption parameters for NSAID removal. The presence of pharmaceutical compounds (PCs) in waters has concerned the scientific community because of their occurrence, persistence, and potentially deleterious effects on human health and aquatic ecosystems. Consequently, studies on the removal of PCs have intensified in the last decade. Because of the lack of deep analysis of this subject, the present study aimed to review the main methods for nonsteroidal anti-inflammatory drug (NSAID) removal from aqueous matrices using biosorbents. The study focused on the adsorption process using adsorbents derived from agro-industrial residues: raw materials, activated materials, biochar, and activated carbon. For this purpose, an overview of publications between 2011 and 2021 was performed on the scientific databases. The consulted literature focused on NSAIDs of highest incidence in water matrices (acetaminophen, ketoprofen, diclofenac, ibuprofen, naproxen, and paracetamol). The evaluated articles report several procedures for preparing and modifying adsorbent materials, in addition to studies concerning the equilibrium, kinetics, and thermodynamics of the adsorption process. Agro-industrial residues converted into activated carbon were the most reported and had improved performance compared to less-processed biosorbents. The use of adsorbents derived from agro-industrial residues is a promising strategy for NSAID removal from water and wastewater. However, further investigations are necessary to provide reliable parameters aimed at upscaling water treatment on a large scale.

Fiber-rich ingredients obtained from agroindustrial residues through combined hydrothermal-chemical processes

The objectives of this study were to evaluate the composition and techno-functional properties of fiber-rich ingredients that were obtained from three agroindustrial residues (oat, soybean, and coffee hulls) through a one-step hydrothermal-chemical combined process. The residues were subjected to an alkaline hydrogen peroxide treatment (2%, pH 11.5) combined with a hydrothermal treatment in an autoclave (121 °C/30 min/1.5 atm). Ash, protein, and lipid contents decreased for all residues, and total (up to 86 g/100 g) and insoluble dietary (up to 83 g/100 g) fiber contents increased for all processed residues. All treated samples exhibited an increase in hydration capacity, with values ranging from 5.2 to 6.6 g/g of water absorption capacity and 5.6 to 5.7 g/g of swelling capacity. The one-step process was efficient in improving the nutritional and techno-functional quality of the residues of oat, soybean, and coffee, and it can be considered a promising alternative for future obtaining of new fiber-rich ingredients.

EFFECT OF ORGANIC MATTER ON THE DEGRADATION OF CEFALEXIN WITH TiO2

In this study, the transformation mechanism of cefalexin (CFX) via TiO2 photocatalysis and the roleof humic acids extracted from two agro-industrial residues, coffee (HAc) and rice (HAa) husks wereevaluated. During the TiO2 photocatalysis, 90% CFX degradation was found after 180 min ofirradiation (365 nm); in the presence of HAc and HAa, 37% and 61% CFX degradation wereobserved, respectively. This shows that the extracted humic acids do not promote the formation ofreactive oxygenated species; further, they act as scavengers of hydroxyl (.OH). Additionally, it wasfound that CFX degradation by heterogeneous catalysis with TiO2 is mainly associated with holeoxidation (47%) and it is caused by •OH radicals in solution (38%). Finally, we can conclude that therole of humic acids as photosensitizers or scavengers is related to their structural properties.