Agro-industrial Residues Research Articles

Enhancing Methane Yield in Anaerobic Co-Digestion of Primary Sewage Sludge: A Comprehensive Review on Potential Additives and Strategies

Traditionally, anaerobic digestion has been applied to mixed sludge, combining primary sludge (PS) with secondary sludge. However, recent research has unveiled the advantages of dedicated PS digestion due to its higher energy content. Anaerobic digestion (AD) of primary sewage sludge can offer a sustainable solution for managing sewage sludge while generating renewable energy. The present study provides a comprehensive examination of the current state of knowledge regarding the anaerobic digestion of PS. Co-digestion of PS with organic substrates, including food waste and agro-industrial residues, emerges as a promising approach to boost biogas production. Additionally, the utilization of additives such as glucose and clay minerals has shown potential in improving methane yield. Critical factors affecting AD, such as pretreatment methods, carbon-to-nitrogen (C/N) ratio, temperature, pH, volatile fatty acids (VFAs) levels, organic loading rates (OLR), inoculum-to-substrate ratio (ISR), and the role of additives, have been meticulously studied. Finally, this review consolidates existing knowledge to advance our understanding of primary sewage sludge anaerobic digestion, fostering more efficient and sustainable practices in sludge management and renewable energy generation.

Pesticide abatement using environmentally friendly nano zero valent particles as photo-Fenton catalyst

Nano-zero valent iron particles (NZVI) have been used for the pesticide pirimicarb degradation under simulated solar radiation. These particles have been synthesized by extracts from agro-industrial residues, namely vineyard and blueberry pruning, black tea and algae, so they can be labelled as “green-NZVI”. The physico-chemical properties of these green-NZVI were compared to those of NZVI synthesized with NaBH4. The usage of agro-industrial residues as reducing agent not only provided better performant NZVI but also evade the usage of harmful reagents. Indeed, this process is not only within circular economy, and environmentally friendly, but also defeats the degradation performance of the widely reported photo-Fenton process with Fe2+ catalyst. 96.5 % pirimicarb degradation was achieved under simulated solar radiation within 15 min with 0.08 mM H2O2 and 0.16 mM NZVI synthesized with black tea extract. Further, the developed process was optimized in terms of reagents concentration and natural antioxidant extract used for NZVI synthesis, which demonstrated a strong effect on pirimicarb degradation due to the differences on natural phenolic compounds present on them. The pirimicarb degradation pathway was analysed, confirming the successful pesticide degradation. In terms of H2O2 concentration, it can be reduced by its sequential addition in time. Under optimal conditions, even real effluents can be successfully degraded.

Efficient Decontamination: Caffeine/Triclosan Removal using Rice Husk in Batch and Fixed-Bed Columns

Abundant, easily accessible, and low-cost agro-industrial residues represent attractive alternatives for removing emerging contaminants from water. In this work, the aqueous adsorption of caffeine/triclosan onto rice husk (RH) was studied in batch and continuous processes. For this purpose, adsorbents with three particle size ranges (120–150, 300–600, 800–2000 µm) were prepared and evaluated. The composition, structure, surface morphology, functionality, and specific surface area of the RH biosorbents were determined. This characterization revealed that RH primarily consists of lignin, cellulose, and hemicellulose, making up to 80.1% of its composition. RH also exhibited an irregular surface, with several functional groups (OH, C=O, CH, C=C, C-OH), and a relatively small specific surface area (1.18 m2/g). Batch tests were carried out using different RH sizes, doses (1–50 g/L), and contact times (5–300 min), using 20 mL of caffeine/triclosan solutions (30 mg/L). Tests were conducted to fit the most adequate kinetics and isotherm models. The optimal doses (g/L) for caffeine and triclosan removal were 4.5 and 1.5 with small RH, 8.5 and 2.5 with medium RH, and 50.0 and 10.0 with large RH, respectively. The optimal contact times for all three particle sizes were 180 and 60 min. Triclosan removal was greater than that of caffeine (2.5–25.5%) with all three particle sizes, requiring less adsorbent (2.5–5.0 times) and shorter times (3 times). The experimental data fit better the Sips isotherm and Elovich kinetics models. The small (120–150 µm) particles achieved the highest caffeine/triclosan batch adsorption capacities (6.3/28.6 mg/g). Continuous tests were performed on fixed-bed columns of 1 cm in diameter, packed with 4, 5, and 8 cm of RH, operated with hydraulic loading rates between 2 and 4 m3/m2day. Small particles also reached the highest adsorption capacity in the removal of caffeine (352.7 mg/L) and triclosan (3797.2 mg/L), and the experimental data were well-fitted to the Bohart–Adams model. The research results not only demonstrate the effective removal of contaminants but also illustrate the versatility and applicability of rice husk in various conditions and systems.

Use of agro-industrial bio-waste for the growth and production of a previously isolated Bacillus thuringiensis strain

BackgroundBacillus thuringiensis (Bt) is a widely used biopesticide. The bioinsecticide based on Bt is obtained by fermentation, but the substrates currently used for its production constitute ingredients of high commercial value. In this context, the use of agro-industrial residues as substrates is an alternative to make the fermentation process viable on a large scale, in addition to minimizing environmental problems and contributing to the destination of these residues for biotechnological purposes.ResultsIn the first part of this study, a previously isolated spore forming soil bacteria (Bv5) harboring and expressing a novel cry 8A gene was confirmed as B. thuringiensis based on its morphological characteristics, Gram staining, scanning electron microscopy (SEM) and genome sequencing. Bv5 was established as a Gram-positive spore forming bacteria with ellipsoidal spores and small round toxins. Bv5 genome comprised of the 5.30 Mb chromosome and two megaplasmids of 450 kb and 261 kb, respectively, with cry 8A gene located on the smallest megaplasmid. In the second part of the study, the physiological profile of the Bv5 strain during fermentation in different agro-industrial biowastes (cassava wastewater, orange pulp wash and whey) was analyzed. The fermentation experiment was divided into two stages. In the first stage, the agro-industrial waste with or without salts with the best results for biomass, spores and proteins production was selected. In the second stage, the effect of the selected medium in original and diluted form with the C:N balance was evaluated, in two different fermentation times (72 h and 96 h). Pulp wash enriched with salts was selected as the most suitable medium for the growth of Bv5 strain in the first stage. In the second stage pulp wash (without dilution) with the addition of salts, and with nitrogen supplementation, was considered the best for cell growth, spore and toxin production by Bv5.ConclusionsTo conclude, our study provide a new alternative for bio-waste from the orange juice industry, as well as potential culture medium for the Bt commercial scale production.

A systematic study on the characteristics and applications of laccases produced by fungi: insights on their potential for biotechnologies

Laccases are polyphenol oxidase enzymes and form the enzyme complex known for their role in wood decomposition and lignin degradation. The present study aimed to systematically review the state-of-the-art trends in scientific publications on laccase enzymes of the last 10 years. The main aspects checked included the laccase-producing fungal genera, the conditions of fungal growth and laccase production, the methods of immobilization, and potential applications of laccase. After applying the systematic search method 177 articles were selected to compound the final database. Although various fungi produce laccase, most studies were Trametes and Pleurotus genera. The submerged fermentation (SmF) has been the most used, however, the use of solid-state fermentation (SSF) appeared as a promising technique to produce laccase when using agro-industrial residues as substrates. Studies on laccase immobilization showed the covalent bonding and entrapment methods were the most used, showing greater efficiency of immobilization and a high number of enzyme reuses. The main use of the laccase was in bioremediation, especially in the discoloration of dyes from the textile industry and the degradation of pharmaceutical waste. Implications and consequences of all these findings in biotechnology and environment, as well as the trends and gaps of laccase research were discussed.

Bio-oil from coconut fibers: fractionation by preparative liquid chromatography for phenols isolation

The great potential of bio-products generated from agro-industrial residues from the biomass processing, as is the case with the green coconut fibers (Cocos nucifera L. var. dwarf), makes Brazil stand out in the field of transformation of these residues, mainly due to its high biodiversity and favorable climatic conditions. In this work, residual green coconut fibers were used in the production of bio-oil by pyrolysis. The bio-oil was fractionated using preparative liquid chromatography (PLC) in silica using solvents of different polarities: hexane, hexane/toluene, toluene/dichloromethane, dichloromethane/acetone, and methanol. Bio-oil and its fractions were analyzed by gas chromatograph /quadrupole mass spectrometer (GC/qMS). The concentration of each compound was carried out by multiplying the percentage area of the corresponding peak by the mass yield of the respective fraction. PLCof bio-oil increased the number of compounds identified by about 170% compared to the original bio-oil (non-fractionated), besides allowing the isolation of nonpolar compounds (mostly hydrocarbons) from polar compounds (mainly phenols, aldehydes, and ketones). Anotheradvantage of PLC was the increase in the number of hydrocarbons identified in the fractions, as opposed to the crude bio-oil analysis. Among the major compounds, phenols can be highlighted, besides furfural derivatives and hydrocarbons, which indicates the potential use of bio-oil mainly for industrial purposes.

Use of murici (Byrsonima crassifolia) and jabuticaba (Plinia cauliflora) residues in the preparation of porous materials: Effect of pH on the adsorption efficiency of the contaminants phenol, diethylphthalate and amoxicillin

Activated charcoals with the chemical activator (H3PO4) were synthesized from agro-industrial residues, Murici seeds (CA-MU) and Jabuticaba (CA-JA). The synthesized charcoals were characterized by thermogravimetric analysis (TG), N2 adsorption and desorption isotherms, Fourier transform infrared spectroscopy (FTIR), point of zero charge (pHPZC) and scanning electron microscopy (SEM). The charcoals produced presented mesoporous characteristics, surface areas of 884.226 m2.g−1 for CA-JA and 556.97 m2.g−1 for CA-MU, mean pore diameters suitable for adsorption of phenol (PHE), diethylphthalate (DEP) and amoxicillin (AMX). The chemical characterization indicated the acid profile of the surface of the charcoals, which presented pHPZC of 6.3 (CA-JA) and 6.7 (CA-MU). The adsorption studies, in aqueous solution of the pollutants (PHE), (DEP) and (AMX), indicated that the removal capacity is strongly influenced by the pH of the solution. Toxicity tests demonstrated that the adsorption process was responsible for decreasing the toxicity of the pollutants studied. Thus, given the results presented, the activated charcoals synthesized can be considered high potential adsorbents for applications in the removal of organic pollutants in aqueous solutions.

Standardization of the Cultivation of Rhizopus arrhizus Using Agroindustrial Residues: High Production of Amylases in Pineapple Peel

Standardization of the Cultivation of Rhizopus arrhizus Using Agroindustrial Residues: High Production of Amylases in Pineapple Peel

Exergoeconomic evaluation of fuel production from rice husk residue through the pyrolysis process

Some agro-industrial wastes are currently untreated, resulting in an increase in greenhouse gas emissions. Therefore, in relation to the pollution generated by fossil fuels, the study of the obtained fuels from agro-industrial and forestry residues has been promoted. Rice is a basic product for several families in the world, and its residue is a component that has enormous potential in Colombia due to its consumption. The objective of the present study is to conduct an exergoeconomic evaluation of the production of fuel from rice husks as agro-industrial waste by means of the slow and fast pyrolysis process. Using simulators like Aspen Plus, the simulation of the two processes was carried up, implementing a rigorous kinetic model. The yield values were validated with data from the literature, obtaining values of 42.3% and 41.4% for slow and fast pyrolysis, respectively, for pyrolytic oil. The total investment cost of the process is 2146.45 kUSD. According to the thermodynamic parameters of the simulator, an exergy analysis was conducted for the two processes. Overall exergy percentages of 73.84% and 78.19% were obtained for the slow and fast pyrolysis, respectively. The economic and exergy analysis was coupled to implement a specific exergy costing. The exergoeconomics factors obtained values of 72.21% and 76.78%, for the slow and fast pyrolysis reactors, respectively. The contribution of the present research is related to the rigorous kinetic model, in addition to its implementation in slow pyrolysis, involved in the exergoeconomic study of biomass pyrolysis processes.

By-Products of the Babassu Agribusiness for Ruminant Diets.

The use of babassu agro-industrial residues in animal feed, in addition to being an economic option of great importance in reducing the environmental impact in regions of the Brazilian Cerrado, provides the production of good quality foods of animal origin due to its nutritional characteristics. However, information related to the nutritional components of babassu by-industrial residues has not yet been sufficiently explored. The aim of this study was to evaluate the nutritional potential of some by-products from the babassu production chain through chemical composition and in situ degradability analyses. The experiment was conducted in a completely randomized experimental design, with 4 by-products from babassu processing (cake, greasy, fine flour, and 95 µm flour) and 5 replications. The by-products differ in terms of chemical composition, except for the hemicellulose content. For the degradability of fraction "a" of dry matter, it presented a higher percentage for 95 µm flour. Fine flour and 95 µm flour presented the highest fractions "b" and "c," potential, and effective degradability of dry matter. For the degradation of crude protein, the highest percentages of potential and effective degradability were observed for greasy and 95 µm flour. The highest standardized potentially degradable fraction and the highest passage rate were obtained by 95 µm flour, which also showed greater degradation for dry matter, crude protein, and neutral detergent fiber. Among the by-products studied, the babassu cake has superior chemical composition; however, the 95 µm flour presented nutritional value and satisfactory rumen degradation to be used as an additive or in partial replacement of traditional concentrates.

Optimización de una bebida con exudado de cacao Theobroma cacao L. CCN51 y suero láctico usando superficie respuesta

The aim of this research was to characterize rheologically a drink formulated and elaborated with exudate of cocoa (Theobroma cacao L.) CCN51 and lactic serum. The formulation was optimized using the response surface methodology for the attributes color, smell, taste and acceptability; subsequently, a multiple surface analysis was performed to determine the global optimal parameters by means of the desirability function. The results ensure that the proportion exudate and lactic serum should be 40/60 with 10% sucrose. The rheology of the beverage shows that it is a non-Newtonian fluid of the pseudoplastic type. In general, temperature and storage time have a significant effect on the flow index and consistency index. The proximal and microbiological chemical tests meet the standards, and the drink is suitable for human consumption. The rheological results of drinks based on cocoa exudate and lactic whey can be used as a parameter for quality control and sizing of machines, equipment, pipes, connections, filters, drive pumps and research provide knowledge for the use of agro-industrial residue. and the dairy industry.

Valorization of agro-industrial wastes using fungi for industrial enzymes production

Huge quantities of the agricultural wastes are produced from practices related to industrial processing, which are mainly burned and thrown in landfills, becoming a threat to the human health and causing environmental pollution. Agro-industrial residues, such as sugarcane bagasse, orange peel, wheat bran, corn straw, barley, rice straw, corn cob, husk, soy bran, and coffee husk were considered as valuable raw materials that can be converted into products of biotechnological interest using microorganisms. Agro-industrial wastes rich in nutrients, such as proteins, minerals, and sugars that, used as possible low cost substrates, for the fungal cultivation, thus considered as an alternative eco-friendly tool for many biological products of economic value, such as enzymes. Fungi organisms are capable of synthesizing a wide range of relevant oxidative and hydrolytic extracellular enzymes, such as peroxidases, laccases, xylanases, and cellulases. The enzymes secreted fungi, are proteins that function as bio-catalysts, responsible for carrying out various biochemical reactions, which applied in food, detergent, cellulose, paper, cosmetics and textile industries, etc. Thus, the replacement of raw materials with lignocellulosic-sources can result in reducing environmental problems and resolving the pollution associated with their disposal, in addition a higher investment will be gained. Therefore, a review was carried out on the important value of agro-industrial wastes, and the cultivation of fungal isolates for economic production of the industrially important enzymes, based on submerged and solid-state fermentation processes, as well as the important application of these enzymes.

Agro-Industrial Residues Used as Substrates for the Production of Bioaroma Compounds with Basidiomycetes: A Comprehensive Review

Flavoring compounds are substances that directly influence the acceptance or rejection of a product. They are considered as essential components in the industrial sector due to their wide range of applications in different areas, such as food, cosmetics and pharmaceuticals. With the growing demand and concern of consumers for the acquisition of flavors from natural products, alternatives for the sustainable and low-cost production of such compounds becomes mandatory. Among these alternatives, biotechnological processes involving fungi are considered ecologically suitable and sustainable, as they tend to use conditions that are less harmful to the environment. The application of filamentous fungi such as basidiomycetes in biotechnological processes has been very promising, although it depends on the strain and growing conditions for obtaining bioaromas. The present review aims to compile reports on the potential of several basidiomycete fungi in the production of bioaromas using biotechnological methods. This review also includes the availability of nutrients and covers the new perspectives created with the application of agro-industrial residues as alternative cultivation substrates for these microorganisms. Thus, this is expected to consequently alleviate environmental pollution problems and enable the production of promising volatile compounds in a natural and sustainable way.

Influence of Coconut Fiber Waste and Rice Husk Ash on Green Concrete

Purpose: To develop cementitious materials, concrete, incorporating coconut fiber waste (CFW) and rice husk ash (RHA), with the aim of producing innovative, cost-effective, and readily available products for use in economically and environmentally friendly construction applications. Environmental impacts can be minimized by making these practices efficient and sustainable through the utilization of these waste materials. Theoretical framework: The use of agro-industrial waste in concrete matrices has been extensively studied due to their effectiveness in influencing material properties. The incorporation of coconut fiber waste and rice husk ash into concrete can lead to improvements in compressive strength, increased durability, and a reduction in the amount of CO2 generated during production. The concrete developed with the incorporation of waste products has the potential to minimize environmental impacts, reduce costs, and extend its lifespan. The pursuit of sustainability drives the exploration of innovative materials to preserve natural resources and mitigate ecological impact in the construction industry. Method: The coconut fiber waste was subjected to 24-hour drying process in an oven at 100°C to remove moisture and was subsequently crushed in a ball mill until its particle size exhibited characteristics similar to the binder. The CFW and RHA were characterized through Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), and Specific Surface Area analysis. Different percentages of CFW (0.25% - 0.75%) and RHA (2% - 10%) were separately incorporated into the concrete mix. The mixing ratio used was 1:1.9:3.1 (cement, sand, aggregate), with a water-to-cement (w/c) ratio of 0.60. Workability tests, electrical resistivity tests, capillary water absorption by capillary rise, and axial compressive strength tests were conducted. Additionally, a sulfate ion penetration test was performed by immersing specimens in a 2.5% sulfuric acid (H2SO4) solution for 7 days. Results: SEM images of CFW reveal an angular and fibrous microstructure, maintaining the original properties of the waste even after its transformation into ash. RHA particles exhibit irregular shapes and sizes with microporous cellular structures on the surface, consistent with literature. X-Ray Diffraction patterns of CFW indicate a material without a distinct crystalline structure. However, Electron Dispersive Spectroscopy analysis suggests the predominance of carbon (C), potassium oxide (K2O), and silica (SiO2). RHA shows broad amorphous diffraction at 22° and some sharp diffraction peaks, suggesting the formation of crystallites, consistent with cristobalite. There was a slight improvement in the workability of fresh concrete compared to the reference mix as the percentage of waste incorporation increased. The electrical resistivity of the produced specimens showed a significant increase in all cases, except for the 0.25% RHA sample. The 5.0% CFW content exhibited the best performance, with a 29.47% increase, indicating a microstructure with few voids and suggesting greater material durability. Samples with higher fiber percentages showed higher water absorption values. Concrete incorporated with RHA exhibited higher porosity and suboptimal performance. However, the incorporation of 0.25% CFW showed a slight improvement compared to the reference concrete. The best performances observed in the compressive strength test were with 5.0% RHA and 0.5% CFW, with the latter showing the best result compared to the reference specimens. In the sulfate attack test, only the concrete with 5.0% RHA showed better performance in an aggressive environment. Increasing the percentage of CFW also reduced mass loss, suggesting potential improvement of the compound at higher proportions. The study demonstrated that agro-industrial residues can be satisfactorily utilized in construction, and the implementation of this new process can reduce global warming and mineral resource depletion. Research implications: This work contributes to a sustainable circular economy with a novel process for utilizing agro-industrial waste in concrete. Originality/Value: The findings will be promising for the utilization of coconut fiber waste and rice husk ash in the production of environmentally sustainable concrete.

Nitrogen-Doped Activated Biocarbon from the Agroindustrial Residue of Jatropha Oilcake for Symmetric Supercapacitors: a Study on the Effect of Activation Temperature

Nitrogen-Doped Activated Biocarbon from the Agroindustrial Residue of Jatropha Oilcake for Symmetric Supercapacitors: a Study on the Effect of Activation Temperature

Lactic acid production from cashew apple bagasse, an agro-industrial waste, and its application in the enzymatic synthesis of polylactic acid

The use of cashew apple bagasse hemicellulose hydrolysate (CABH) to produce lactic acid by two strains of lactic acid bacteria, Lactobacillus plantarum FJ05311 and L. plantarum FJ05315, was evaluated. The application of cashew apple bagasse (CAB) would enhance the establishment of a biorefinery from this agro-industrial residue since its main compounds, cellulose, hemicellulose, and lignin, can be used to obtain several bioproducts. The influence of essential parameters was studied for the production of LA. The CABH contained mainly glucose and xylose at concentrations of approximately 40 g/L and 20 g/L, respectively. The process conducted at 30 °C, 100 rpm, and using the culture in the final of the growth phase (inoculum time of 24 h for LAB07 and 20 h for LAB14) and urea as nitrogen source enhanced the LA production for both strains, LAB07 and LAB14, reaching 24.3 g/L. The produced LA was used to synthesize polylactic acid (PLA) for the enzymatic route using lipase B from Candida antarctica (CALB). Then, the production of PLA from cashew apple bagasse hydrolysate is a sustainable alternative to produce a biodegradable polymer with many industrial applications and obtaining personal protective equipment to use in the current and future pandemics.

Effect of adding micronized eggshell waste particles on the properties of biodegradable pectin/starch films

Upcycling agroindustry residues into new valuable products is a strategy for mitigating environmental impacts while increasing material circularity. In this study, two sizes of eggshell particles (D90 = 7.1 μm (ESAJ) and D90 = 16.3 μm (ESBU)) were obtained and their incorporation as fillers into biodegradable pectin/starch film was evaluated. The effect of the presence of eggshell particles (2–8 w/w%) on the structural and morphological aspects, water barrier, and mechanical, optical, and thermal properties of the biocomposites was evaluated and then the reinforced film was applied on the surface of kraft paper. The release of calcium in an acidic solution was inverse to the size and concentration of particles and the released íon may contribute to the crosslinking of pectin. The incorporation of only 2 % eggshell resulted in 42% lower solubility of the film. The eggshell-reinforced films proved to be more opaque and rigid. The addition of 6% ESAJ significantly improved the tensile strength (an increase of 32%), modulus of elasticity (an increase of 29.7%), and water vapor barrier (59% of improvement). DSC analysis suggests that the calcium from the eggshell interacts with the pectin polymeric structure, reducing the sites available for water molecules, which may have caused more mobility of the chains through the matrix. The reinforced pectin/starch film was very well adhered to the kraft paper in the application test by continuous casting, but the coated paper showed no improvement in oil and water resistance, which means that other coating processes need to be explored.

Mechanical strength and Life Cycle Assessment (LCA) of soil-cement: comparison between mixtures of soil with ASTM type III cement, LC3, and the incorporation of by products and agroindustrial residues

Soil stabilization with binders is based on the binder action on soil particles, in turn causing an improvement in the mechanical behavior of the soil. Thus, this study aims to analyze the mechanical and environmental properties of soil-cement mixtures using Portland ASTM type III cement as binders and comparing to LC3 (Limestone Calcined Clay Cement), as well as incorporating extra raw materials such as silica fume, fly ash, sugarcane bagasse ash (Saccharum officinarum L) and açai seed ash (Euterpe precatoria Martius). The mixtures of soil, binder, extra raw materials were performed manually, and the cylindrical specimens (100 mm internal ø) were molded based on the AASHTO Normal Test. The results showed that the highest values of compressive strength ranged between 10 and 11 MPa, which were recorded for reference, soil-LC³ and soil-LC-açai seed ash mixtures. Life Cycle Assessment (LCA) was performed using the CML 2001 method with the aid of the OpenLCA software. Additionally, it was observed that the main emissions and consequences for the environment were from mixtures containing higher clinker contents.

Production of fungal phytases in solid state fermentation and potential biotechnological applications.

Phytases are important enzymes used for eliminating the anti-nutritional properties of phytic acid in food and feed ingredients. Phytic acid is major form of organic phosphorus stored during seed setting. Monogastric animals cannot utilize this phytate-phosphorus due to lack of necessary enzymes. Therefore, phytic acid excretion is responsible for mineral deficiency and phosphorus pollution. Phytases have been reported from diverse microorganisms, however, fungal phytases are preferred due to their unique properties. Aspergillus species are the predominant producers of phytases and have been explored widely as compared to other fungi. Solid-state fermentation has been studied as an economical process for the production of phytases to utilize various agro-industrial residues. Mixed substrate fermentation has also been reported for the production of phytases. Physical and chemical parameters including pH, temperature, and concentrations of media components have significantly affected the production of phytases in solid state fermentation. Fungi produced high levels of phytases in solid state fermentation utilizing economical substrates. Optimization of culture conditions using different approaches has significantly improved the production of phytases. Fungal phytases are histidine acid phosphatases exhibiting broad substrate specificity, are relatively thermostable and protease-resistant. These phytases have been found effective in dephytinization of food and feed samples with concomitant liberation of minerals, sugars and soluble proteins. Additionally, they have improved the growth of plants by increasing the availability of phosphorus and other minerals. Furthermore, phytases from fungi have played an important roles in bread making, semi-synthesis of peroxidase, biofuel production, production ofmyo-inositol phosphates and management of environmental pollution. This review article describes the production of fungal phytases in solid state fermentation and their biotechnological applications.

Biorefinery of peanut shell agroindustrial lignocellulosic waste for synthesis of a natural coagulant applied in the treatment of dairy wastewater

Agro-industrial lignocellulosic residue from peanut shell was used to obtain a natural coagulant, cationic hemicelluloses (CH), adding value to the residue through means of biorefinery. The hemicellulose was applied, after its cationization by etherification reaction in alkaline medium with ETA, as a natural coagulant in the treatment of synthetic dairy effluent (SDE). FTIR showed an increase of the methyl group band in 1480 cm-1, degree of substitution DS 0.38 ± 0.05 and the positive zeta potential of +13.1 ± 0.5 mV CH indicating the insertion of ETA in the structure hemicelluloses whose zeta potential was negative of ‐11.4 ± 0.6 mV. The evaluation of the CH was performed with jartest on turbidity, apparent color, and COD for a pHcoagulation range 5–11 and dosages from 50-500 ppm. Coagulation diagrams were determined using the data spatial interpolation method of the adapted Kringing regression model. The maximum performance of CH of SDE by sedimentation and DAF occurred at 50 ppm and pH 11 with turbidity removal efficiency, true color and chemical oxygen demand (COD) of 84.74%/87.48%, 98.75%/99.37% and 99.89%/93.38%, respectively. Flake morphology was analyzed through the application of an image capture non-intrusive method indicated low particle aggregation, with fractal dimension (Df) of the flakes stabilized in the range of 1.68–1.83 ± 0.020 in 15 min with a predominance of flakes with first-class flake diameters (0.022–1.20 mm) for all dosages. That explains the slower sedimentation and occurrence of smaller dispersed flakes which favored subsequent solid-liquid separation by DAF.