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.

Sequential Process of Subcritical Water Hydrolysis and Hydrothermal Liquefaction of Butia Capitata Endocarp to Obtain Fermentable Sugars, Platform Chemicals, Bio-oil, and Biochar.

Butia capitata endocarp (BCE) is a biomass residue with the potential to produce a wide variety of bio-products. The processing of BCE in a sequential process of subcritical water hydrolysis (SWH) and hydrothermal liquefaction (HTL) was investigated to obtain fermentable sugars, platform chemicals, bio-oil, and biochar. The SWH was evaluated at 230 and 260 °C and solvent: feed mass ratios (R) of 10 and 20 for the production of fermentable sugars and platform chemicals. The solid residue from SWH was sequentially submitted to the HTL at 330 and 360 °C for bio-oil and biochar production. The results were analyzed by comparing the sequential (SWH/HTL) and individual (HTL only) processes. The highest yields of fermentable sugars (5.26 g/ 100 g BCE) were obtained for SWH at 260 °C and R-20 with higher contents of xylose (2.64 g/100 g BCE) and cellobiose (1.75 g/100 g BCE). The highest yields of platform chemicals (2.44 g/100 g BCE) were obtained for SWH at 260 °C and R-10 with higher contents of acetic acid (1.78 g/100 g BCE) and furfural (0.54 g/100 g BCE). The highest yield of bio-oil (25.30 g/100 g BCE) occurred in HTL individual process at 360 °C and R-20. Sequential process SWH/HTL showed a decrease in bio-oil yield but maintained a similar biochar yield compared to HTL, in addition to the production of fermentable sugars and platform chemicals.

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.

Microencapsulation of Brazilian Cherokee blackberry extract by freeze-drying using maltodextrin, gum Arabic, and pectin as carrier materials.

There are many blackberry cultivars in Brazil; however, the characteristics and applications of the Cherokee cultivar have not yet been widely studied. For this reason, this research investigated the behaviour of maltodextrin (MD), gum Arabic (GA), and pectin (PEC), as carriers combined in different proportions (20% MD, 15% MD + 5% GA, 15% MD + 5% PEC), on encapsulation of Cherokee blackberry pulp extract obtained by freeze-drying. The results of moisture content (2.73-3.36%), water activity (aw) (0.11-0.15), solubility (52.40-54.11%), hygroscopicity (17.59-21.11%), colour (hue 0.24-0.32), retention of anthocyanins (51.55-60.53%), total phenolic compounds (39.72-70.73 mg GAE/100g), antioxidant activity at 25 mg/mL (77.89-80.02%), IC50 (12.26-14.53), simulated in vitro digestion and morphology were discussed. Concerning morphology, blackberry powders had irregular structures and amorphous structures. Comparatively, the best results were obtained for MD-GA. MD-GA presented the highest content of phenolic compounds (70.73 ± 1.84 mg GAE/100g) and antioxidant activity (80.02%), as well as the lowest IC50 value (12.26). In general, all powders showed an increase in phenolic compounds during in vitro digestion, because of the pH conditions and digestive enzymes present in the simulated digestive fluid. This result shows that the wall material provides protection, since the blackberry rich extract (RE) showed degradation of phenolic compounds in in vitro digestion. In this sense, freeze-drying is a suitable technique for the encapsulation of Cherokee blackberry pulp extract.

Adsorption of basic fuchsin using soybean straw hydrolyzed by subcritical water.

The valorization of agro-industrial residues can be improved through their full use, making the production of second-generation ethanol viable. In this scenario, hydrolyzed soybean straw generated from a subcritical water process was applied to the basic fuchsin adsorption. At pH eight, a high adsorption capacity was obtained. The mass test results showed that basic fuchsin's removal and adsorption capacity could be maximized with an adsorbent dosage of 0.9 g L-1. The linear driving force model was suitable for predicting the kinetic profile, and the kinetic curves showed that equilibrium was reached with only 30 min of contact time. Besides, the Langmuir model was the best to predict the adsorption isotherms. The thermodynamic parameters revealed a spontaneous and endothermic process. At 328 K, there is maximum adsorption capacity (72.9 mg g-1). Therefore, it can be stated that this material could be competitive in terms of adsorption capacity coupled with the idea of full use of waste.

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.

Production of Protein Hydrolysate from Quinoa (Chenopodium quinoa Willd.): Economic and Experimental Evaluation of Two Pretreatments Using Supercritical Fluids' Extraction and Conventional Solvent Extraction.

Supercritical fluids' extraction (SFE) and conventional solvent extraction (CSE) for defatting of quinoa flour as pretreatments to produce the quinoa protein hydrolysate (QPH) were studied. The objective was to extract the oil and separate the phenolic compounds (PC) and the defatted quinoa flour for subsequent quinoa protein extraction and enzymatic hydrolysis. The oil extraction yield (OEY), total flavonoid content (TFC), and QPH yield were compared. SuperPro Designer 9.0® software was used to estimate the cost of manufacturing (COM), productivity, and net present value (NPV) on laboratory and industrial scales. SFE allows higher OEY and separation of PC. The SFE oil showed a higher OEY (99.70%), higher antioxidant activity (34.28 mg GAE/100 g), higher QPH yield (197.12%), lower COM (US$ 90.10/kg), and higher NPV (US$ 205,006,000) as compared to CSE (with 77.59%, 160.52%, US$ 109.29/kg, and US$ 28,159,000, respectively). The sensitivity analysis showed that the sale of by-products improves the economic results: at the industrial scale, no significant differences were found, and both processes are economically feasible. However, results indicate that SFE allows the recovery of an oil and QPH of better nutritional quality and a high level of purity-free organic solvents for further health and nutraceutical uses.

Microwave hydrodiffusion and gravity model with a unique hydration strategy for exhaustive extraction of anthocyanins from strawberries and raspberries.

This study aimed to verify if microwave hydrodiffusion and gravity (MHG) could efficiently extract anthocyanins from strawberries and raspberries with low environmental impact and costs. Our findings revealed that it was possible to extract 69 and 64% anthocyanins from the strawberries and raspberries in a single extraction step, respectively. When the co-product (product remaining after extracting in natura fruits) was hydrated with green solvents and subjected to re-extraction, it was possible to exhaustively extract the anthocyanins from both fruits. Using the Green Analytical Procedure Index (GAPI), the MHG proved to cause low environmental impact due to the solvents used, enabling the reuse of the co-product for food and pharmaceutical products application. Moreover, the MHG was economically viable, and the sample pretreated with distilled water was the most indicated re-extraction method. The MHG process proved to be exhaustive for strawberry and raspberry anthocyanins, thus demonstrating to be an excellent alternative for sustainable extraction.

Low-frequency ultrasound-assisted esterification of Bixa orellana L. seed starch with octenyl succinic anhydride.

This study aimed to evaluate the impact of the ultrasound intensity (0, 5, 10, and 20 W/cm2) on the esterification of annatto (Bixa orellana L.) seed starch with octenyl succinic anhydride (OSA) employing a short processing time (5 min) to produce a novel emulsifier. OSA-esterified annatto seed starches were examined according to their degree of substitution (DS), amylose content, granule size distribution, microstructure, and X-ray diffractogram. Also, the performance of the OSA-modified annatto seed starch to stabilize colloidal systems was compared to commercial samples of OSA-modified starches. For this, annatto seed oil-in-water emulsions were produced and characterized according to their droplet size distribution, microstructure, and kinetic stability. Increasing ultrasound intensity from 5 W/cm2 to 20 W/cm2, DS values reached up to 0.139 ± 0.031. Likewise, these treatments yielded approximately 1.24-1.36 times more amylose content than the sample without ultrasound application. Most of the starch granules presented smooth surfaces without visible fissures. The higher ultrasound intensity hindered the aggregation of starch granules, thus forming well-defined elliptical particles. On the other hand, the increase of the ultrasound intensity did not change Brouckere mean diameter of the starch granules. No significant qualitative differences were seen in the X-ray diffractograms in terms of diffraction angle and peak intensity, indicating that the main functional characteristics of starches were not altered with ultrasound treatment. Furthermore, modified annatto starch was able to stabilize annatto seed oil-in-water emulsions. When compared to two commercial modified starches, OSA-esterified annatto starch produced a colloidal system with a larger Sauter mean diameter (14 ± 2 µm). However, the emulsion stabilized with modified annatto starch was more kinetically stable during the storage time in comparison to those stabilized with commercial starches.

Hydrothermal carbonization and Liquefaction: differences, progress, challenges, and opportunities.

Thermochemical processes including hydrothermal technology are gaining research interest as a potentially green method for deconstructing biomass into platform chemicals or energy carriers. Hydrothermal liquefaction (HTL) and Hydrothermal Carbonization (HTC) are advantageous because of their enhanced process performance while being environmentally friendly and technologically innovative. However, after a deep review, several works have shown a misunderstanding between HTL and HTC concepts. Therefore, this review advances understanding on the main differences and gaps found between HTL and HTC in terms of operation parameters, technical issues, and main products. Furthermore, environmental and techno-economic assessments (TEA) were presented to appraise the environmental sustainability and economic implications of these techniques. Perspectives and challenges are presented and the integration approaches of hydrothermal valorization pathways and biorefining are explored.

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.

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.

Hydrothermal pretreatment of lignocellulosic biomass for hemicellulose recovery.

The hemicellulosic fraction recovery is of interest for integrated processes in biorefineries, considering the possibility of high economic value products produced from their structural compounds of this polysaccharide. However, to perform an efficient recovery, it is necessary to use biomass fractionation techniques, and hydrothermal pretreatment is highlighted as a valuable technique in the hemicellulose recovery by applying high temperatures and pressure, causing dissolution of the structure. Considering the possibility of this pretreatment technique for current approaches to hemicellulose recovery, this article aimed to explore the relevance of hydrothermal pretreatment techniques (sub and supercritical water) as a strategy for recovering the hemicellulosic fraction from lignocellulosic biomass. Discussions about potential products to be generated, current market profile, and perspectives and challenges of applying the technique are also addressed.

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.

Microwave hydrodiffusion and gravity as pretreatment for grape dehydration with simultaneous obtaining of high phenolic grape extract.

The present study aimed to verify the efficiency of microwave hydrodiffusion and gravity (MHG) by partially removing water from grapes while simultaneously obtaining a phenolic-rich extract. In addition, the effect of heating on phenolic compound degradation of pre-dehydrated grapes, the extract, and economic viability to produce both products were evaluated. Thus, a 50% reduction of moisture in the grapes was observed after 10 min while simultaneously obtaining a grape extract. Both products obtained by MHG presented high phenolic compound content and antioxidant capacity. In addition, the use of MHG on an industrial scale was found to be economically viable based on the analysis time, labor cost, and financial return of the products obtained. Thus, the method is efficient, fast, economically viable, and sustainable while simultaneously producing pre-dehydrated grapes and a phenolic-rich extract.

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.