Submerged cultivation of Nigrospora sp. in batch and fed-batch modes for microbial oil production.

Microbial lipids are a valuable source of potential biofuels and essential polyunsaturated fatty acids. The optimization of the fermentation conditions is a strategy that affects the total lipid concentration. The genus Nigrospora sp. has been the target of investigations based on its potential bioherbicidal action. Therefore, this study developed a strategy to maximize the biomass concentration and lipid accumulation by Nigrospora sp. in submerged fermentation. Different media compositions and process variables were investigated in shaken flasks and bioreactor in batch and fed-batch modes. Maximum biomass concentration and lipid accumulations were 40.17 g/L and 21.32 wt% in the bioreactor, which was 2.1 and 5.4 times higher than the same condition in shaken flasks, respectively. This study presents relevant information to the production of fungal lipids since few investigations are exploring the fed-batch strategy to increase the yield of fungi lipids, as well as few studies investigating Nigrospora sp. to produce lipids.

New frontiers of soil fungal microbiome and its application for biotechnology in agriculture.

The fungi-based technology provided encouraging scenarios in the transition from a conventionally based economic system to the potential security of sources closely associated with the agricultural sphere such as the agriculture. In recent years, the intensification of fungi-based processes has generated significant gains, additionally to the production of materials with significant benefits and strong environmental importance. Furthermore, the growing concern for human health, especially in the agriculture scenario, has fostered the investigation of organisms with high biological and beneficial potential for use in agricultural systems. Accordingly, this study offered a comprehensive review of the diversity of the soil fungal microbiome and its main applications in a biotechnological approach aimed at agriculture and food chain-related areas. Moreover, the spectrum of opportunities and the extensive optimization platform for obtaining fungi compounds and metabolites are discussed. Finally, future perspectives regarding the insurgency of innovations and challenges on the broad rise of visionary solutions applied to the biotechnology context are provided.

Evaluation of ultrasound waves for the production of chitinase and ß-1,3 glucanase by Trichoderma harzianum through SSF.

Cell wall degrading enzymes (chitinase and ß-1,3-glucanase) were produced by solid-state fermentation (SSF) using the fungus Trichoderma harzianum and different agro-industrial products, mainly residues. The influence of temperature (25-35 °C), initial moisture content (50-90% w/w), nutrient solution (1-2% v/w), and yeast extract (1-2% w/w) on enzyme activity was evaluated. The application of ultrasound during fermentation for different times (0-6 h/day) was also studied. White rice was the substrate that showed the highest chitinase and ß-1,3-glucanase activities, which were 31.31 U/g for chitinase and 23.83 U/g for ß-1,3-glucanase after 10 days of fermentation. Application of ultrasound waves during fermentation positively affected (p < 0.05) the enzyme activities. The best results for chitinase (51.88 U/g) and ß-1,3-glucanase (39.22 U/g) were obtained with a 50% (w/w) moisture content and 4 h/day ultrasound application for 10 days of fermentation. Increases of 3.6-fold (from 14.37 to 51.88 U/g) and 3.8-fold (from 10.22 to 39.22 U/g) in activities for chitinase and ß-1,3-glucanase, respectively, compared to non-sonicated fermentation, were obtained. Ultrasound technique associated with the SSF process was a promising alternative to increase the production activity of cell wall degrading enzymes: chitinase and ß-1,3-glucanase.

Weed control by metabolites produced from Diaporthe schini.

Weed control is a critical factor to ensure productivity and quality for food production. Chemical control is the main method used worldwide, but the demand for healthier food and the farmers' health and environment concerns have led to an increase in the search for alternative control methods. In this way, the use of biomolecules produced by microorganisms that present phytotoxic activity against weeds, such as exopolysaccharides, is attracting attention. For this purpose, this work compared two techniques (solid-state and submerged fermentation) for bioherbicide production by Diaporthe schini. Physicochemical characterization of both fermented broth and evaluation of bioherbicidal effect in post-emergence of Amaranthus viridis, Bidens pilosa, Echinocloa crusgalli, and Lollium multiflorum were performed. Fungal broth obtained by submerged fermentation presented better physicochemical characteristics in terms of viscosity, density, and surface tension. Overall, it was more effective than the broth obtained by solid-state fermentation for weed control because it presented an average inhibition of 40% of weed growth and 45% lower surface tension if compared to the control test. Also, reductions of 1.4-4.2 times of root dry mass, 2.9-5.8 times of shoot dry mass and 1.2-3.9 times of weeds heights, if compared to the control test, were achieved.

Powder containing biomolecules from Diaporthe schini for weed control.

This study describes the use of spray drying technology to obtain a powder containing biomolecules with herbicidal activity produced by submerged fermentation using Diaporthe schini. The efficiency of the bioherbicide was tested for the post-emergence control of Bidens pilosa L., Amaranthus viridis L., Echinochloa crusgalli (L.) Beauv., and Lolium multiflorum Lam. In the first step, different additives were used and lactose was the most suitable one because it resulted in high herbicidal activity and weed suppression. In the second step, process variables were investigated, including inlet air temperature, drying air flow rate, and feed flow rate. The highest herbicidal activity was obtained with an inlet air temperature of 100°C, and air and feed flow rates of 1.4 m3/min and 0.22 L/h, respectively. Maximum herbicidal activities were 38, 45, 21 and 18%, while weed heights reduction were 69.0, 74.3, 20.4 and 24.8% for B. pilosa, A. viridis, E. crusgalli and L. multiflorum, respectively. The bioherbicide was effective to suppress weed growth and spray drying is a promising technology for the production of solid formulations of bioherbicides.

Ultrasound as an alternative method to increase the extraction yield from chicken mecanically separated meatresidue collagen.

The residue from chicken mechanically separated meat (MSM) is a potential source for the extraction of collagen. However, this process requires the removal of many covalent crosslinks, which makes it quite complex. Ultrasound has been successfully used to extract collagen; it reduces the process time and increases the yield. However, information regarding the effects of this treatment on the structural and functional properties of proteins is still very limited. Therefore, the aims of the present study were to obtain collagen from chicken MSM residue and to test the effects of pre-treatment with ultrasonic probe and enzymatic extraction with pepsin in its yield, as well as to evaluate the properties of extracted collagen using gel electrophoresis, Fourier-transform infrared spectroscopy, solubility, and differential scanning calorimetry. Both the ultrasound and the enzymatic extraction had a positive effect on the extraction yield of collagen from chicken MSM residue without affecting its integrity. Using ultrasound led to an increase of up to 40% in yield when compared to treatments without ultrasound application. Five extraction treatments were considered. The extracted collagen exhibited high thermal stability (43.9-47.0 °C) and mainly type I structure. The use of ultrasound as pre-treatment, together with enzymatic extraction with pepsin, were effective in increasing the extraction yield of collagen from chicken MSM residue, as well as preserving the triple helical structure of the native collagen.

Extraction of bioactive compounds from Senecio brasiliensis using emergent technologies.

Several plant species synthesize biologically active secondary metabolites. Pyrrolizidine alkaloids are a large group of biotoxins produced by thousands of plant species to protect against the attack of insects and herbivores, but they are highly toxic for humans and animals. In this study, extracts from the aerial part of Senecio brasiliensis were obtained using different technologies: ultrasound-assisted extraction (UAE), pressurized liquid extraction (PLE), and microwave hydrodiffusion and gravity (MHG). The study aimed to evaluate the effectiveness of these technologies for the extraction of chemical compounds found in this plant, focusing on two pyrrolizidine alkaloids: integerrimine and senecionine. Influential parameters on yield and chemical composition were also evaluated: for UAE and MHG, temperature and pressure; for PLE, temperature, and percentage of ethanol. All the extraction techniques were efficient for the extraction of integerrimine and senecionine. The UAE and PLE stood out for the higher yields and number of compounds. The PLE presented a maximum yield of 18.63% for the matrix leaf and the UAE a maximum yield of 11.82% for the same matrix. These two techniques also stood out in terms of the number of compounds, once 36 different compounds were found via PLE and 17 via UAE. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-021-02845-1.

Production of biofuels from soybean straw and hull hydrolysates obtained by subcritical water hydrolysis.

The objective of this study was to evaluate the ethanol production by Wickerhamomyces sp. using soybean straw and hull hydrolysates obtained by subcritical water hydrolysis and, afterward, the biogas production using the fermented hydrolysates. Ethanol was produced using the straw and hull hydrolysates diluted and supplement with glucose, reaching 5.57 ± 0.01 g/L and 6.11 ± 0.11 g/L, respectively. The fermentation in a bioreactor with changing the pH to 7.0 allowed achieving maximum ethanol production of 4.03 and 3.60 g/L for straw and hull hydrolysates at 24 h, respectively. The biogas productions obtained for the fermented hydrolysates of straw with and without changing the pH were 739 ± 37 and 652 ± 34 NmL/gVSad, respectively. The fermented hydrolysate of hull without changing the pH presented 620 ± 26 NmL/gVSad. The soybean residues produced biofuels, indicating these residues show potential as raw material for renewable energy production.

Extraction and characterization of polysaccharide-enriched fractions from Phoma dimorpha mycelial biomass.

Ultrasound-assisted extraction (UAE) and pressurized hot water extraction (PHWE) were tested as advanced clean methods to obtain polysaccharides from Phoma dimorpha mycelial biomass. These methods were compared to conventional extraction (hot water extraction, HWE) in terms of polysaccharides-enriched fractions (PEF) yield. A central composite rotational design was performed for each extraction method to investigate the influence of independent variables on the yield and to help the selection of the condition with the highest yield using water as an extraction solvent. The best extraction condition of PEF yielded 12.02 wt% and was achieved when using UAE with direct sonication for 30 min under the intensity of 75.11 W/cm2 and pulse factor of 0.57. In the kinetic profiles, the highest yield (15.28 wt%) was obtained at 50 °C under an ultrasound intensity of 75.11 W/cm2 and a pulse factor of 0.93. Structural analysis of extracted polysaccharide was performed using Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and thermal property. The water solubility index, water holding capacity, and emulsification index of PEF were 31.3 ± 1.5%, 138.1 ± 3.2%, and 62.9 ± 2.3%, respectively. The submerged fermentation demonstrates the huge potential of Phoma dimorpha to produce polysaccharides with bioemulsifying properties as a biotechnologically cleaner alternative if compared to commercial petroleum-derived compounds. Furthermore, UAE and PHWE are green technologies, which can be operated at an industrial scale for PEF extraction.

Different techniques for concentration of extracellular biopolymers with herbicidal activity produced by Phoma sp.

The natural ability of microorganisms to secrete high levels of bioactive compounds make them attractive hosts for producing novel compounds. Microbial biopolymers have potential applications in most of the sectors of the world economy. According to the physicochemical properties, they present some advantages, such as biodegradability, reproducibility, and stability. Based on this context, the objective of this work was to evaluate different methods for concentration and characterisation of extracellular biopolymers produced by Phoma sp. Extracellular biopolymers were produced by submerged fermentation and were concentrated by hollow fibre membranes and by adsorption. The structural characterisation of purified biopolymers was determined by Fourier Transform Infrared spectroscopy. Phytotoxic effects were assessed through absorption assays in detached leaves of Cucumis sativus and evaluated on the seventh day after application. The surface tension was evaluated for each sample. Hollow-fibre microfiltration membrane presented a higher purification factor than hollow-fibre ultrafiltration membrane. Extracellular biopolymers were identified in the permeate and retentate fractions, but in higher concentration in the retentate fractions. The adsorption process was efficient for recovering more than 88% of extracellular biopolymers from cell-free fermented broth. The best performance was obtained by using silica and activated carbon as adsorbent, with a recovery higher than 93%. The herbicidal activity was proportional to the concentration of biopolymers and the results are very promising for future applications because a concentrated solution of biopolymers can increase weed control. Membrane processes can be used to develop a liquid formulation of bioherbicide, whereas adsorption can be used to develop a solid formula.

An overview of fungal biopolymers: bioemulsifiers and biosurfactants compounds production.

Fungal biopolymers have gained considerable attention from the scientific community for various applications due to their biological and physicochemical properties. The wide applications in several areas, especially in the food industry as a bioemulsifier and in the agricultural area as a biosurfactant, have expanded the knowledge on the production of fungal biopolymers to keep up with developments on this subject area. Recent scientific studies have disclosed novel routes, optimized parameters, increased yields, and other related approaches in order to produce and apply fungal bioemulsifiers and biosurfactants. However, there is a need to gather important information in order to provide a way forward. Therefore, this review presents an overview of properties, applications, and perspectives for encouraging further projects and investments in the near future by most categories of investors. The selection of culture media, the definition of cultivation parameters, extraction, recovery, and purification are the initial steps to indicate the conditions for scale-up. Indeed, scale-up is still one of the challenges in this biotechnological field, which could be solved by expanding the tests and operational productions in both pilot and industrial plants.

Optimization of subcritical water hydrolysis of pecan wastes biomasses in a semi-continuous mode.

Pecan cultivation has increased in recent years. Consequently, the amount of lignocellulosic residuals from its production has expanded. Thus, there is a necessity to explore and add value to their coproducts. The objective of this work was to obtain reducing sugars from pecan biomasses by the optimization of the subcritical water hydrolysis technology in a semi-continuous mode and the physicochemical and morphological characterization of these materials, such as SEM, TGA and FT-IR analysis. Temperatures of 180, 220 and 260 °C, water/solids mass ratio of 15 and 30 g water/g biomass and total reaction time of 15 min were used. The highest reducing sugar yield was 27.1 g/100 g of biomass, obtained at 220 °C and R-15 for pecan shells. TGA, SEM and FT-IR analysis indicated the modifications of structures and compositions of biomasses in fresh and hydrolyzed samples.

Solid wastes from the enzyme production as a potential biosorbent to treat colored effluents containing crystal violet dye.

Sugarcane bagasse, a largely available waste worldwide, was submitted to solid-state fermentation (SSF) using the fungus Metarhizium anisopliae, aiming to produce enzymes. The solid waste generated from SSF was tested as an alternative biosorbent to treat colored effluents containing crystal violet (CV) dye. The biosorbent, here named BW (bagasse waste), was characterized, and experimental tests were performed to verify the influence of pH and dosage on the CV biosorption. Isotherms and biosorption kinetics were performed, and the biosorption thermodynamic parameters were determined. The potential of BW was also evaluated for the treatment of a simulated textile effluent. The maximum biosorption capacity was 131.2 mg g-1 at 328 K, and the Liu was the most appropriate model to represent equilibrium data. The biosorption was spontaneous and endothermic. The use of BW in the simulated effluent showed that it is an efficient material, reaching color removal values of 85%. Therefore, the sugarcane bagasse generated from SSF can be considered a potential biosorbent to remove CV from textile effluents. This finding is relevant from the total environment viewpoint, since, at the same time, SSF generates enzymes and a solid waste, which in turn can be used as biosorbent to treat colored effluents.

Concentration of exopolysaccharides produced by Fusarium fujikuroi and application of bioproduct as an effective bioherbicide.

Exopolysaccharides are secondary metabolites produced by microorganisms and are a subject of research in many fields of science and industry due to some of their confirmed properties, especially in the pharmaceutical and agrochemical areas. In this context, the objectives of this work were to evaluate the potential of Fusarium fujikuroi for producing exopolysaccharides and to concentrate such compounds in order to increase the herbicidal activity. Exopolysaccharides were produced by submerged fermentation and different concentration methods (membranes, lyophilization, and evaporation) were evaluated. The phytotoxic effects were assessed through absorption assays in detached leaves of Cucumis sativus and evaluated on the seventh day after application. The surface tension was evaluated for each concentration method. The production of exopolysaccharides in the crude broth without concentration was 5.94 g/L. When using the lyophilization method, a maximum yield of exopolysaccharides of 10.64 g/L was obtained. The membranes also presented satisfactory results of exopolysaccharides: 9.60 g/L. The increase of bioherbicidal activity and the lower surface tension are proportionally related to the increase of the concentration of exopolysaccharides.

Application of Beauveria bassiana spore waste as adsorbent to uptake acid red 97 dye from aqueous medium.

The adsorption of acid red 97 dye (RED 97) by the waste of the filamentous fungus Beauveria bassiana was analyzed. The adsorbent was obtained as a waste of a fermentative process, and characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffractometry (XRD), and specific surface area (BET). After the characterization, adsorption tests were carried out to determine the ideal conditions of pH, adsorbent mass, and contact time for the process. Adsorption isotherms, thermodynamic studies, and the treatment of textile effluent were also investigated. The adsorbent characterization allowed the visualization of its amorphous structure, with irregular and heterogeneous particles. The pore diameter was 51.9 nm and the surface area was 0.247 m2 g-1. 1.2 g L-1 of the adsorbent and pH of 2.0 were the ideal conditions for RED 97 adsorption. The pseudo-second-order kinetic model was the most appropriate to represent the experimental data, being the equilibrium reached in about 110 min. The Langmuir model was the most suitable to represent the equilibrium data, with maximum adsorption capacity of 194.1 mg g-1 at 45 °C. The adsorption processes was thermodynamically spontaneous, favorable, and exothermic. In the treatment of a real textile effluent, 5 g L-1 of the spores was capable to decolorize 70% of the solution. Therefore, spore wastes of Beauveria bassiana were promising for RED 97 adsorption.

Improving the soluble lipase-catalyzed biodiesel production through a two-step hydroesterification reaction system.

The application of lipases in liquid formulation instead of immobilized forms in the enzymatic biodiesel synthesis can make the process cost-efficient, more competitive, and sustainable. However, despite the benefits, the long reaction times required to achieve satisfactory yields is still a drawback of this biotechnological process. In this sense, employing the novel low-cost soluble NS40116 lipase, this paper proposes an innovative two-step hydroesterification reaction (TSHR) system as a technique of improving the reaction rate of an enzymatic biodiesel production. With the employment of two central composite statistical design to optimize the parameters of each of the reactions involved, the influence of the parameters "water concentration added to the reaction," "methanol-to-oil molar ratio," and "lipase load" on the process yield, besides the acid value of the samples, was investigated. After only 8 h of reaction, the highest fatty acid methyl ester yield reached was 97.1% with an acid value of 4.62 mg KOH g-1 utilizing a total of 8 wt% water, methanol-to-oil molar ratio of 6.3:1, and 0.70 wt% of lipase. Furthermore, the statistical models for both reactions indicated to be significant with 95% of reliability. Considering that the papers published using soluble lipases in a one-step batch process normally reach similar yields to those obtained in this research after 16 h to 24 h of reaction, the proposed system demonstrated to be a promising option of process configuration for the enzymatic production of biodiesel.

Adsorption of 2-nitrophenol using rice straw and rice husks hydrolyzed by subcritical water.

The potential of rice husks and straw as adsorbents after being processed by subcritical water hydrolysis (SWH) was investigated. The influences of temperature (453, 493 and 533 K) and liquid/solid ratio (7.5 and 15 g water/g biomass) on the rice straw and rice husks characteristics and on the adsorption capacity of 2-nitrophenol were evaluated at pH 4 and 7. Adsorption kinetics, equilibrium and thermodynamic parameters were also studied. The adsorption capacity was favored at pH 7. Pseudo-first-order model was suitable to predict the kinetic curves for 2-nitrophenol concentrations of 25, 50, 75 and 100 mg/L and the isotherm data obeyed the Freundlich model. Overall, the thermodynamic results revealed a spontaneous and exothermic process. The maximum adsorption capacity (92.97 ±â€¯1.31 mg/g) was obtained for rice straw that has undergone an SWH at 453 K and 7.5 g water/g straw. The integration of processes to valorize co-products can make the production of cellulosic bioethanol more feasible.

Production of cutinase by solid-state fermentation and its use as adjuvant in bioherbicide formulation.

In the present study, it was presented a strategy to maximize the cutinase production by solid-state fermentation from different microorganisms and substrates. The best results were observed using Fusarium verticillioides, rice bran being the main substrate. Maximum yield of cutinase obtained by the strain was 16.22 U/g. For concentration, ethanol precipitation was used, and the purification factor was 2.4. The optimum temperature and pH for enzyme activity were 35 °C and 6.5, respectively. The enzyme was stable at a wide range of temperature and at all pH values tested. The concentrated cutinase was used as an adjuvant in a formulation containing cutinase + bioherbicide. The use of enzyme increased the efficiency of bioherbicide, since cutinase was responsible to remove/degrade the cutin that recovery the weed leaves and difficult the bioherbicide absorption. Cutinase showed to be a promising product to be used in formulation of bioherbicides.

Cellulolytic enzyme production from agricultural residues for biofuel purpose on circular economy approach.

This study evaluated the production of cellulolytic enzymes from different agricultural residues. The crude enzyme extract produced was characterized and applied for saccharification of some agricultural residues. Maximum cellulolytic activities were obtained using soybean hulls. All enzymatic activities were highly stable at 40 °C at a pH range of 4.5-5.5. For stability at low temperatures, the enzyme extract was stored at freezing temperature and cooling for about 290 days without major loss of activity. The Km values found for total cellulase (FPase), endoglucanase (CMCase), and xylanase were 19.73 mg ml-1, 0.65 mg ml-1, and 22.64 mg ml-1, respectively, and Vmax values were 0.82 mol min-1 mg-1, 0.62 mol min-1 mg-1, and 104.17 mol min-1 mg-1 to cellulose, carboxymethyl cellulose, and xylan, respectively. In the saccharification tests, the total amount of total reducing sugars (TRS) released from 1 g of soybean hulls catalyzed by the enzymes present in the crude enzyme extract was 0.16 g g-1 dry substrate.

Concentration of metabolites from Phoma sp. using microfiltration membrane for increasing bioherbicidal activity.

This study is focused on the concentration of fermented broth from Phoma sp. to increase its herbicidal activity. For this purpose, biomolecules produced by submerged fermentation using Phoma sp. were concentrated by hollow fiber microfiltration membranes. The membrane feed was separated into two streams (retentate and permeate) and the crude broth was concentrated to 10, 30, 50, 70 and 90% (relative to the initial volume). The retentate samples were submitted to bioassays (triplicate) for evaluating their phytotoxic effects on five young leaves of species of Cucumis sativus and also on pre-emergence of weeds as Bidens pilosa and Amaranthus retroflexus. The highest herbicidal activity was 80.7% obtained for a concentration of 30% in the retentate fraction. At this condition, the bioherbicide presented severe damage symptoms on the detached leaves of Cucumis sativus if compared to the crude fermented broth. In the pre-emergence of B. pilosa and A. retroflexus, 100% control was obtained for assays performed in a germination chamber. For greenhouse assays using the substrate, the control rate of A. retroflexus was dependent of concentration of bioherbicide. The promising results achieved in the research with membrane separation process allow us to propose and develop further studies for evaluating this technology in the concentration of other metabolites produced by fermentation which also have bioherbicidal activity.