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Glutathione (GSH) and peroxidase (POD) are biomolecules of interest in the global market; thus, it is desirable to seek ways to increase their production. Magnetic field (MF) application is one of the technologies used in cultivation that has shown promising results to increase bioproducts. Therefore, this study aimed at evaluating the influence of MFs on GSH and POD production by Saccharomyces cerevisiae ATCC 7754. Different periods of MF application (35 mT) were evaluated over 72 h. The highest GSH production was reached in 48 h of cultivation in assays MF 0-24 (155.32 ± 9.12 mg L

Spirulina is a filamentous microalga which is considered a promising alternative source of essential nutrients and active biomolecules. High production cost and the space required to install a photobioreactor are two of the greatest challenges in the industrial application of microalga-based products. Thus, this study aimed to improve Spirulina sp. LEB 18 biomass and phycocyanin content by combining the application of mixotrophic culture and magnetic fields (MF). Zarrouk medium was modified with 1 and 3 g/L liquid molasses and the application of 30 mT for 1·h/d was investigated. Mixotrophic culture with 1 g/L molasses showed the highest biomass concentration (1.62 g/L), carbohydrate content (25.6%), and lipid contents (8.7%) after 15 days. Although the combination of 30 mT and 1 g/L liquid molasses decreased biomass production (1.44 g/L), there was increase in protein yield (76.9%) and protein productivity (73.8 mg/L·d). The proposed method increased phycocyanin production by 145% and its purity from 0.584 in the control culture to 0.627. Data described by this study show that the combination of mixotrophic culture and MF application is a promising alternative to increase microalga protein and phycocyanin production.

This study aimed to investigate the effects of magnetic field (MF) application (1, 12 and 24 h day −1) to Spirulina sp. LEB 18 in different photosynthesis cycles (dark and/or light) during short (15 days) and long periods (50 days) of cultivation. MF application was performed via two sources: ferrite magnets and solenoids. At the end of cultivation, the biomass was characterized in terms of lipids, proteins, and carbohydrates. In the 15 day cultures, the highest maximum biomass concentrations (2.06 g L−1 and 1.83 g L−1) were observed when 30 mT was applied for 24 h day −1 or 12 h day −1 (on the light cycle), respectively. MF application throughout cultivation (24 h day −1) for more than 30 days is not recommended. In all conditions, there was an increase in the lipid concentration (from 14 to 45%). The protein profile suggested important changes in photosystems I and II due to MF application. Cell morphology was not altered by MF application. In conclusion, the effects on the metabolism of Spirulina sp. are directly related to the photosynthesis cycle and time period in which the MF was applied.

Os carotenoides são a classe de pigmentos mais difundida na natureza. Possuem alta demanda de mercado devido as suas propriedades benéficas a saúde, resultando em aumento nas pesquisas referentes à sua produção via biotecnológica, podendo estes, serem produzidos por diferentes micro-organismos como a levedura Phaffia rhodozyma. Para tanto, pesquisas são necessárias para avaliar métodos e técnicas de extração e recuperação mais eficientes destes produtos. Neste contexto, este estudo propõe avaliar diferentes pré-tratamentos na biomassa de P. rhodozyma e diferentes solventes para a recuperação de carotenoides. Para tal, três pré-tratamentos na biomassa foram avaliados (secagem 24 h – congelamento 24 h; secagem 48 h – congelamento 48 h e liofilização). A utilização de hexano e éter de petróleo como solvente para a obtenção do extrato carotenogênico também foi verificada. Com o aprimoramento da metodologia, obteve-se máxima concentração específica (245,71 ± 6,08 µg g-1) e volumétrica (1803,50 ± 36,46 µg L-1) de carotenoides utilizando éter de petróleo no pré-tratamento com secagem 24 h (35 °C) e congelamento 24 h (-18 °C). Este resultado mostra que no ensaio 24 h a quantidade de carotenoides extraído da biomassa é 23,3% mais eficiente que o método usualmente utilizado (secagem 48 h - congelamento 48 h), reduzindo o tempo de processo em 48 h.

This study aimed to evaluate the influence of a magnetic field (MF) intensity of 25 mT on Chlorella fusca cultivation in outdoor and indoor conditions, and evaluate the changes in the macromolecules, pigment content and protein profile. C. fusca was cultivated for 15 d in raceway photobioreactor. MF was applied for 24 h d−1 and 1 h d−1. In outdoor cultivation, MF applied for 24 h d−1 increased 23% in the biomass concentration, while indoor assays resulted in an increase in both modes, with biomass production increasing between 70 and 85%. Biomass composition was altered when MF was applied for 1 h d−1 in indoor assays; the highest protein content was achieved (32.7%). Nitrate consumption was higher in outdoor assays, while MF application did not alter the protein profile. The results showed that combining the outdoor conditions with MF is advantageous, as higher biomass concentration can be achieved with lower energy expenditure.

Several studies have shown that any magnetic field (MF) applied to microalgae modifies its cultivation conditions and may favor biomolecule production since it interacts with the microorganisms and affect their growth. As a result, there are changes in concentrations and compositions of biomass and biomolecules. This review aims at updating MF applications to microalga cultures that were reported by studies conducted in the last 5 years. It shows the main studies that reached positive results of carbohydrate, lipid, protein and pigment production. Effects of MFs may be positive, negative or null, depending on some factors, such as intensity, exposure time, physiological state of cells and application devices. Therefore, this review details cultivation conditions used for reaching high concentration of biomolecules, explains the action of MFs on microalgae and describes their applicability to the biorefinery concept. info:eu-repo/semantics/publishedVersion

A priority of the industrial applications of microalgae is the reduction of production costs while maximizing algae biomass productivity. The purpose of this study was to carry out a comprehensive evaluation of the effects of pH control on the production of Nannochloropsis gaditana in tubular photobioreactors under external conditions while considering the environmental, biological, and operational parameters of the process. Experiments were carried out in 3.0 m3 tubular photobioreactors under outdoor conditions. The pH values evaluated were 6.0, 7.0, 8.0, 9.0, and 10.0, which were controlled by injecting pure CO2 on-demand. The results have shown that the ideal pH for microalgal growth was 8.0, with higher values of biomass productivity (Pb) (0.16 g L−1 d−1), and CO2 use efficiency ( $$E_{\text{CO}_{2}}$$ ) (74.6% w w−1); $$R_{\text{CO}_{2}}$$ /biomass value obtained at this pH (2.42 $$\text{g}_{\text{CO}_{2}}$$ gbiomass−1) was close to the theoretical value, indicating an adequate CO2 supply. At this pH, the system was more stable and required a lower number of CO2 injections than the other treatments. At pH 6.0, there was a decrease in the Pb and $$E_{\text{CO}_{2}}$$ ; cultures at pH 10.0 exhibited a lower Pb and photosynthetic efficiency as well. These results imply that controlling the pH at an optimum value allows higher CO2 conversions in biomass to be achieved and contributes to the reduction in costs of the microalgae production process.

Glutathione (L-γ-glutamyl-cysteinyl-glycine, GSH) is a tripeptide synthesized through consecutive enzymatic reactions. Among its several metabolic functions in cells, the main one is the potential to act as an endogenous antioxidant agent. GSH has been the focus of numerous studies not only due to its role in the redox status of biological systems but also due to its biotechnological characteristics. GSH is usually obtained by fermentation and shows a variety of applications by the pharmaceutical and food industry. Therefore, the search for new strategies to improve the production of GSH during fermentation is crucial. This mini review brings together recent papers regarding the principal parameters of the biotechnological production of GSH by Saccharomyces cerevisiae. In this context, aspects, such as the medium composition (amino acids, alternative raw materials) and the use of technological approaches (control of osmotic and pressure conditions, magnetic field (MF) application, fed-batch process) were considered, along with genetic engineering knowledge, trends, and challenges in viable GSH production. KEY POINTS: • Saccharomyces cerevisiae has shown potential for glutathione production. • Improved technological approaches increases glutathione production. • Genetic engineering in Saccharomyces cerevisiae improves glutathione production.

New substrates and fermentation conditions have been drawing researchers’ attention to increase the bioethanol productivity. The aim of this study was to evaluate the acid hydrolysis of Spirulina biomass and its use in association with molasses in ethanol production with and without magnetic field (MF) application. Hydrothermal hydrolysis of Spirulina biomass hydrolysis was evaluated. The highest reducing sugar concentration (79% w w−1) was obtained with sulfuric acid 5% (v v−1), 121 °C, 30 min, and 500 g L−1 of biomass. This hydrolyzed biomass and molasses were used as substrates in the alcoholic fermentation with Saccharomyces cerevisiae by varying the biomass/molasses (B/M) ratio: 25, 50, and 75% (v v−1). The medium 25% B/M had higher ethanol yield at 78.9% and productivity of 0.72 g L−1 h−1. MF application did not increase the cell growth and ethanol production. This is the first study that integrates molasses and microalgal biomass substrates for ethanol production and presents some new information about magnetic fields application that is still little explored in the literature.

BACKGROUND: There is a lack of studies that investigate the application of magnetic field in microalgae cultures in the literature. Aiming to understand the effects of the application of magnetic field, along with illuminance, on the growth of microalgae, an accurate first‐principles mathematical model must be designed and evaluated. Furthermore, the parameters associated with illuminance and magnetic field in the new model must be obtained through a reliable and robust parameter estimation procedure, since for magnetic field effects there are no models and parameters reported in the literature. RESULTS: A new model for microalga growth with application of illuminance and magnetic field was designed to predict biomass productivity. Fourteen different Verhulst‐based mathematical equations were proposed and compared. The results showed the significant influence of the illuminance and magnetic field on the microalga growth and indicated that the designed model accurately fitted the experimental data. CONCLUSIONS: A new model to predict microalga growth with application of illuminance and magnetic field was designed considering two new parameters, KI and KM, affinity of a microorganism to illuminance and magnetic field, respectively, in a Verhulst‐based equation. The parameters were accurately estimated though a hybrid combination of particle swarm optimization and nonlinear least‐squares algorithms, allowing the model to accurately predict microalga growth. © 2019 Society of Chemical Industry

This study aimed to use different conditions of magnetic field (MF) application during Chlorella fusca cultivation and evaluate CO2 biofixation by the microalga through growth kinetics in addition to the biomass composition. For this purpose, we tested different MF intensities applied for 1 h d−1 and for 24 h. Cultures exposed to the MF for 1 h d−1 (in both intensities) had greater biomass concentrations (1.42 g L−1) and 34% more productivity in the same time as the control assay. The biofixation rate increased by 50% with 60 mT for 1 h d−1, and the protein content was enhanced by 30 mT (56.21% w w−1). This study was the first to consider the MF effect on CO2 biofixation. MF applied for 1 h d−1 proved to be an efficient alternative method to increase the CO2 biofixation and growth of C. fusca besides to be an inexpensive and nontoxic method.

Use of fuels from non-renewable sources has currently been considered unsustainable due to the exhaustion of supplies and environmental impacts caused by them. Climate change has concerned and triggered environmental policies that favor research on clean and renewable energy sources. Thus, production of third generation biofuels is a promising path in the biofuel industry. To yield this type of biofuels, microalgae should be highlighted because this raw material contains important biomolecules, such as carbohydrates and lipids. Technological approaches have been developed to improve microalgal cultivation under ecological conditions, such as light intensity, temperature, pH and concentrations of micro and macronutrients. Thus, magnetic field application to microalgal cultivation has become a viable alternative to obtain high yields of biomass concentration and accumulation of carbohydrates and lipids.

Microalgae are able to produce many valuable biomolecules, such as polysaccharides, that presents a large diversity of biochemical structures and functions as antioxidant, antifungal, anticancer, among others. Static magnetic fields (SMF) influence the metabolism of microorganisms and has been shown as an alternative to increase microalgae biomass, yield and compounds production. Especially, some studies have highlighted that SMF application could enhance carbohydrate content. This study aimed to evaluate different conditions of SMF on Spirulina and Chlorella in indoor and outdoor conditions, in order to confirm the influence of SMF on polysaccharides production, evaluating which polysaccharidic fraction could be enhanced by SMF and highlighting a possible modification in EPS composition. Starch from Chlorella and exopolysaccharides (EPS) from Spirulina were quantified and characterized. SMF increased the starch content in Chorella fusca biomass. EPS productions from A. platensis and Spirulina sp. were not significantly increased, and global composition appeared similar to the controls (constituted basically of 80–86% neutral sugars and 13–19% uronic acids). However, the monosaccharide composition analysis revealed a significant modification of composition, i.e., the amount of fucose, arabinose, rhamnose, galactose and glucuronic acid was increased, while the glucose content was decreased. SMF application led to significant modification of polysaccharides production and this study demonstrate that combining the outdoor conditions with SMF, the starch content and EPS composition was positively affected.

Peroxidase is an enzyme in the group of oxidoreductases that is widely distributed in nature. It can catalyze the oxidation of various organic and inorganic substrates by reacting with hydrogen peroxide and similar molecules. Due to its wide catalytic activity, peroxidases can act in the removal of both phenolic compounds and peroxides, in chemical synthesis and, according to recent studies, in mycotoxin degradation. Therefore, this study aimed at introducing an overview of the mechanism of peroxidase action, extraction sources, mycotoxin degradation capacity and other potential applications in the food industry.

Crop yield can be raised by establishment of adequate plant stand using seeds with high germination ratio and vigor. Various pre-sowing treatments are adopted to achieve this objective. One of these approaches is the exposure of seeds to a low-to-medium level magnetic field (MF), in pulsed and continuous modes, as they have shown positive results in a number of crop seeds. On the basis of the sensitivity of plants to MF, different types of MF have been used for magnetopriming studies, such as weak static homogeneous magnetic fields (0–100 μT, including GMF), strong homogeneous magnetic fields (milliTesla to Tesla), and extremely low frequency (ELF) magnetic fields of low-to-moderate (several hundred μT) magnetic flux densities. The agronomic application of MFs in plants has shown potential in altering conventional plant production systems; increasing mean germination rates, and root and shoot growth; having high productivity; increasing photosynthetic pigment content; and intensifying cell division, as well as water and nutrient uptake. Furthermore, different studies suggest that MFs prevent the large injuries produced/inflicted by diseases and pests on agricultural crops and other economically important plants and assist in reducing the oxidative damage in plants caused by stress situations. An improved understanding of the interactions between the MF and the plant responses could revolutionize crop production through increased resistance to disease and stress conditions, as well as the superiority of nutrient and water utilization, resulting in the improvement of crop yield. In this review, we summarize the potential applications of MF and the key processes involved in agronomic applications. Furthermore, in order to ensure both the safe usage and acceptance of this new opportunity, the adverse effects are also discussed.

The aim of this study was to evaluate the influence of the CO2-specific flow rate on pH control, CO2 use efficiency and biomass and lipid productivity of Nannochloropsis gaditana cultivated in outdoor tubular photobioreactors of 3.0 m3. In that study was evaluated the injection of CO2-specific flow rates ranging from 0.4 to 7.7 mL CO 2 Lculture−1 min−1. The use of low CO2-specific flow rates, from 0.4 to 1.9 mL CO 2 Lculture−1 min−1, has enabled pH control. The highest biomass productivities and CO2 use efficiency were obtained using the flow rates of 1.2 and 1.9 mL CO 2 Lculture−1 min−1. The highest lipid productivities were verified in experiments with flow rates of 0.4 mL CO 2 Lculture−1 min−1, followed by 1.9 mL CO 2 Lculture−1 min−1. A high CO2-specific flow rate increases CO2 loss and reduces the performance of the cells due to inadequate pH control. By contrast, a low CO2-specific flow rate prevents adequate pH control and the performance of the cultures. Considering the results provided, an optimal CO2-specific flow rate (1.9 mL CO 2 Lculture−1 min−1) was obtained for outdoor photobioreactor operations to produce N. gaditana, thus contributing to cost reduction.

Magnetic field (MF) can interact with the metabolism of microalgae and has an effect (positive or negative) on the synthesis of molecules. In addition to MF, the use of pentose as a carbon source for cultivating microalgae is an alternative to increase carbohydrate yield. This study aimed at evaluating the MF application on the mixotrophic culture of Chlorella minutissima in order to produce carbohydrates. MF of 30 mT was generated by ferrite magnets and applied diurnally for 12 days. The addition of 5% pentose, MF application of 30 mT, and nitrogen concentration reduced (1.25 mM of KNO3) was the best conditions to obtain higher carbohydrate concentrations. MF application of 30 mT increased biomass and carbohydrate contents in 30% and 163.1%, respectively, when compared with the assay without MF application. The carbohydrate produced can be used for bioethanol production.

The present study was aimed to develop a membrane sparger (MS) integrated into a tubular photobioreactor to promote the increase of the carbon dioxide (CO2 ) fixation by Spirulina sp. LEB 18 cultures. The use of MS for the CO2 supply in Spirulina cultures resulted not only in the increase of DIC concentrations but also in the highest accumulated DIC concentration in the liquid medium (127.4 mg L-1 d-1 ). The highest values of biomass concentration (1.98 g L-1 ), biomass productivity (131.8 mg L-1 d-1 ), carbon in biomass (47.9% w w-1 ), CO2 fixation rate (231.6 mg L-1 d-1 ), and CO2 use efficiency (80.5% w w-1 ) by Spirulina were verified with MS, compared to the culture with conventional sparger for CO2 supply. Spirulina biomass in both culture conditions had high protein contents varying from 64.9 to 69% (w w-1 ). MS can be considered an innovative system for the supply of carbon for the microalgae cultivation and biomass production. Moreover, the use of membrane system might contribute to increased process efficiency with a reduced cost of biomass production.

The aim of this study was to evaluate the influence of different carbon dioxide (CO2 ) concentrations on the distribution of carbon forms in the culture medium and the biomass production and biomolecules productivity of the strain Chlorella fusca LEB 111. In this study, experiments were carried out in which C. fusca cultures were exposed to different CO2 concentrations, 0.03% (0.08 mlCO2 mlmedium -1 days-1 ), 5% (0.18 mlCO2 mlmedium -1 days-1 ), and 15% vol/vol CO2 (0.54 mlCO2 mlmedium -1 days-1 ). Among the carbon chemical species distributions in the culture medium, bicarbonate was predominant (94.2-98.9%), with the highest quantitative percentage in the experiment receiving a 15% CO2 injection. C. fusca LEB 111 cultivated with 15% CO2 showed the highest biomass productivity (194.3 mg L-1 days-1 ) and CO2 fixation rate (390.9 mg L-1 days-1 ). The carbohydrate productivity in the culture that received 15% CO2 was 46.2% higher than the value verified for the culture with the addition of CO2 from the air (0.03% CO2 ). In addition, CO2 concentration providing increases of 0.03-15% to C. fusca cultures resulted in a 31.6% increase in the lipid productivity. These results showed that C. fusca can be used for CO2 bioconversion and for producing biomass with potential applications for biofuels and bioproducts.

Microalgae contribute significantly to the global carbon cycle through photosynthesis. Given their ability to efficiently convert solar energy and atmospheric carbon dioxide into chemical compounds, such as carbohydrates, and generate oxygen during the process, microalgae represent an excellent and feasible carbohydrate bioresource. Microalgae-based biofuels are technically viable and, delineate a green and innovative field of opportunity for bioenergy exploitation. Microalgal polysaccharides are one of the most versatile groups for biotechnological applications and its content can be increased by manipulating cultivation conditions. Microalgal carbohydrates can be used to produce a variety of biofuels, including bioethanol, biobutanol, biomethane, and biohydrogen. This review provides an overview of microalgal carbohydrates, focusing on their use as feedstock for biofuel production, highlighting the carbohydrate metabolism and approaches for their enhancement. Moreover, biofuels produced from microalgal carbohydrate are showed, in addition to a new bibliometric study of current literature on microalgal carbohydrates and their use.

This study aimed at applying different intensities (30 and 60mT) and exposure times (24 and 1hd-1) of MF to cultures of Chlorella kessleri and evaluated their effects on cell growth, proximate composition of biomass, pigment production and antioxidant activity. The condition of 60mT for 1hd-1 stimulated biomass concentration of 83.2% by comparison with control culture (CC). Besides stimulated 13.7% lipid synthesis, 38.9% chlorophyll a and 59.1% chlorophyll b, 25.0% total carotenoids and antioxidants up to 185.7%. Thus MF application is an excellent alternative to stimulate cell growth and high biotechnological interest biocompounds.

Nowadays, discussions about energy-related issues are in evidence. The dynamics of gradual depletion of non-renewable energy reserves, such as oil ones, and global warming have encouraged the search for renewable energy alternatives. The main objective of this work is to evaluate the influence of major operational variables on the transesterification reaction of mixtures of frying oil and bovine tallow, in the presence of methanol, using microwave technology. In an effort to optimize biodiesel production, a statistical design was performed, considering the solvent/feed ratio, the ratio between frying oil and bovine tallow, the amount of KOH, reaction time, and temperature as independent variables. The dependent variables analyzed were biodiesel yield and esters content, obtained by chromatographic analysis. The experiments and the analysis confirmed that a 9:1 solvent/feed molar ratio of, 1.5% catalyst, 35 seconds reaction time, and a mixture containing 70% of frying oil and 30% of bovine tallow provided yields above 89 %. The best conditions to reach 99.43 % of ester content used a 9:1 solvent/feed molar ratio, 0.5 % catalyst, 70%/30% frying oil/bovine tallow, and 35 seconds reaction time.

This study aimed at evaluating mitigation of nivalenol (NIV) in alcoholic fermentation with magnetic field application (MF). Mitigation was related to both the glutathione (GSH) redox molecule and the enzyme peroxidase (PO), which were synthesized by Saccharomyces cerevisiae US-05. Conditions under evaluation were NIV (0.2 µg mL−1), MF application (35 mT) and simultaneous use of mycotoxin and MF. The GSH content and the PO activity were increased when the culture contained NIV and the alcohol profile was altered after 48 h of fermentation. At the end of the alcoholic fermentation, NIV was mitigated by 56.5%. Therefore, this process is a promising method to reduce contamination by NIV, although the mycotoxin affects the chemical characteristics of the final product.

This study evaluated the influence of the magnetic field on the chemical composition of Spirulina sp. LEB 18 and its digestibility and protein solubility. The highest protein digestibility of biomass was obtained at 30 °C and with 2.5 g L−1 NaNO3 (78.4%) in the medium, and the highest solubility was found in the cultivated biomass exposed to 60 mT, 30 °C and 2.5 g L−1 NaNO3 (89%, pH 6). MF application did not modify the protein concentration of biomass, but reduced the carbohydrate concentration by 69.1%, showing that the biomass obtained in the culture submitted to MF may be used as an ingredient in the development of protein supplements.

This study describes the physicochemical properties of soybean asolectin (ASO) liposomes loaded with phycocyanin (Phy) extracted from Spirulina sp. LEB 18. The effects of Phy in the liposomesʾ properties were investigated by Fourier transform infrared spectroscopy (FTIR), 1H and 31P nuclear magnetic resonance (NMR), zeta (ζ)-potential, dynamic light scattering (DLS) and ultraviolet-visible (UV–vis) techniques. Phy restricted the motion of ASO polar and interface groups and disrupted the package arrangement of the lipid hydrophobic regions, as a likely effect of dipolar and π interactions related to its amino acid residues and pyrrole portions. These interactions were correlated to antiradical/antioxidant Phy responses obtained by 2,2-diphenyl-1-picrylhidrazil (DPPH) assay, thiobarbituric acid reactive substances (TBARS) and ferric reducing antioxidant power (FRAP) methods, and discussed to bring new chemical perspectives about Phy-loaded liposomes-related nutraceutical applications in inflammatory and viral infection processes.

Static magnetic fields (SMF) are being studied in microorganism cultures and there are reports that it could accelerate growth or cause changes in metabolism. Thus, this study aims to evaluating the influence of SMF on growth and biomass composition obtained in culture of Chlorella fusca LEB 111 in vertical tubular photobioreactor (VTP). SMF of 30 and 60 mT was generated by ferrite magnets and applied for 24 h d−1 and 1 h d−1 for 15 days. The growth of C. fusca was evaluated by kinetic parameters and the biomass obtained was evaluated by protein, carbohydrate, and lipid content. SMF of 60 mT for 24 h d−1 increased the biomass concentration and the carbohydrate content, it was 20.5% and 24.8% higher than control culture, respectively. Magnetic treatment is a new method to culture microalgae that can accelerate growth and increase compounds of interest, which can be used as food or biofuel.

The carbon dioxide (CO 2 ) emissions from fossil fuels contributes to global warming. This phenomenon became a major political issue in the fields of science, environment, and economy in current years. Microalgae can convert CO 2 into biomass and oxygen through the photosynthesis. The aim of this study was to evaluate the influence of diffusers configuration and CO 2 flow rate in mass transfer, CO 2 fixation efficiency by Spirulina and in the biomass composition produced. Two flow rates (0.05 and 0.3 vvm) and four diffusers (sintered stone (SS), porous curtain (PC), perforated ring (PR) and porous wood (PW)) were used in this study. The maximum CO 2 mass transfer coefficient (123.2 h −1 ) in the CO 2 –H 2 O system corresponded to the higher flow rate (0.3 vvm) using the diffuser porous curtain (PC). The maximum biomass productivity (125.9 ± 5.3 mg L −1 d −1 ) was observed for PC with a flow rate of 0.05 vvm. Increasing the flow rate (0.3 vvm) with PC resulted in a 26% increase in the carbohydrate content in biomass. The results showed a smaller flow rate with porous diffusers might promote an increase in CO 2 fixation efficiency by microalgae.

Succinic acid is a four-carbon dicarboxylic acid used as a building-block in the synthesis of valuable commodities and specialty chemicals. Succinic acid is produced petrochemically by hydrogenation of maleic anhydride and a “greener” alternative route is microbial fermentation. In this study, a 25−1 fractional factorial design (FFD) and a subsequent central composite rotatable design (CCRD) were used to investigate the influence of process parameters on succinic acid and biomass concentration during fermentation by Actinobacillus succinogenes. The independent factors were glucose concentration (19.29–42.45 g/L), yeast extract concentration (5–11 g/L), temperature (33–41 °C), pH (6–8), and agitation speed (100–300 rpm). Results showed that the main factors that influenced the succinic acid production were pH, yeast extract concentration and temperature. According to the CCRD results, the optimum conditions for succinic acid production were 37–41 °C, 13 g/L yeast extract concentration and pH 7. The maximum succinic acid concentration obtained was 17.5 g/L.

This study aimed to use different conditions of magnetic field (MF) application during Chlorella fusca cultivation and evaluate CO

Biosurfactants are active compounds that are produced at the microbial cell surface or excreted, and reduce surface and interfacial tension. Microbial surfactants offer several advantages over synthetic ones, such as low toxicity and high biodegradability, and remain active at extreme pH and salinity. Biosurfactants are produced by bacteria, yeasts, and filamentous fungi. The composition and yield of biosurfactants depends on bioreactor characteristics, pH of the medium, nutrient composition, agitation, oxygen availability, and temperature. Solid-state fermentation conditions allow the use of alternative substrates such as industrial or agricultural by-products to reduce costs. Thus, there is industrial interest in developing large-scale production processes for these compounds. The largest market for biosurfactants is the oil industry; however, the applications are distributed among the various industrial sectors, such as agriculture, cosmetics, and food industries. Based on this, the current chapter reports the processes involved in biosurfactant production.

This study aimed at evaluating whether a magnetic field (MF) affects the growth of Spirulina sp. when applied to it at different exposure times in indoor and outdoor culture systems. The effects of MF on chlorophyll content, medium consumption and protein profile were also investigated. In raceway tanks, a 25 mT MF was applied for 24 h or for 1 h d −1 . MF for 24 h to outdoor assays increased biomass concentration and chlorophyll- a content besides altering the protein profile. Outdoor Spirulina growth was higher (∼3.65 g L −1 ) than the growth found in indoor assays (∼1.80 g L −1 ), while nitrogen and phosphorus consumption was not enhanced by the application of MF. This is the first study that investigated the influence of MF on outdoor microalga assays, and the results showed that MF affected the metabolism of Spirulina cultured in raceways , especially when it was grown outdoors in uncontrolled environmental conditions.

Static or modulated magnetic fields (MF) may interact with the biological system and affect the metabolism of microorganisms, such as their photosynthetic capacity or synthesis of carbohydrates. Their effects on microorganisms, which can be classified into inhibiting, stimulating and null, may be interpreted as the result of stress that cells undergo, thus, leading to responses through the same mechanisms. Biological effects of exposure to magnetic forces depend on magnetic intensity, frequency and exposure time. Modifications in these parameters may enhance product formation. Effects differ according to the form and application of MF characteristic parameters. Magnetic treatments have the advantages of being convenient and non-toxic, having low running cost, emitting no secondary pollution, enabling wide application and being easily shielded. MF application to the cultivation of microalgae, to improve the production of finished biomolecules, is a simple, inexpensive and powerful process. However, bioeffects of MF on microalgae need to be further investigated because there have currently been very few available reports in the literature. Thus, studies which aim at optimizing parameters involved in MF application must be developed in order to obtain the best conditions for the production of molecules with high economic potential.

Lipases have various industrial applications and their production by filamentous fungi in solid state fermentation (SSF) process is of interest. In this work the lipase enzyme production by the mutant Aspergillus niger 11T51A14, which is a well-known lipase producer was studied using wheat bran as substrate. Microorganism used in fermentation process was inoculated at a concentration of 107 spores/gm into the medium containing nitrogen (ammonium sulfate), sunflower soapstock and wheat bran. The SSF process for enzyme production was carried out in aerated columns immersed in a water bath at 32oC for 72 h. The process was studied using a central composite rotatable design 22, where variables tested were the nitrogen concentration (0.32-0.88 % w/w) and the volume of liquid (60.9-89.1 mL). The lipase activity was analyzed in enzymatic extracts. The wheat bran, in the fermentation medium, acted as a carbohydrate source and as an inducer for the lipase production. The maximum enzyme activity found was 153.4 U/gdm, with a nitrogen concentration of 0.6 % and 89.1 mL of volume of liquid. The response surface model demonstrated that higher volume of liquid had a positive effect in lipase activity, while nitrogen concentration showed an optimal range (0.4-0.6%).

Lipases are enzymes that catalyze the hydrolysis of the ester linkage in a triacylglycerol oil-water interface, while in non-aqueous environments they catalyze reverse reactions (esterification, transesterification and interesterification). They can be produced by a solid state fermentation (SSF) process adding value to agro-industrial residues as alkaline soapstocks that can be used as a lipid substrate for lipase production. The objective of this study was to characterize the soapstocks of canola, sunflower and corn and use these byproducts for fungal lipase production using the mutant strain 11T53A14 of Aspergillus niger. The work was carried out following 2 4-1 and 2 3 experimental designs in the presence and absence of inducers, respectively, aiming to evaluate the influence of some variables in the lipase production. The production by SSF was carried out in aerated columns incubated at 32°C. Among the soapstocks evaluated, the sunflower soapstock was the best inducer for enzyme production, with 201 U/gdm (gram of dry medium) using 10 8 spores/gm (gram of medium) inoculated on wheat bran humidified with 80 mL of liquid (ammonium sulfate solution) that corresponds to a final concentration of 0.5% nitrogen, and 3% inducer. The best lipase activity obtained without soapstock was 182 U/gdm under the same processing conditions as the experiment using soapstock. Although the results with the highest lipase activity with sunflower soapstock and without inducer are close, the Tukey test showed a significant difference of these results, which proves the importance of lipid substrate to improve the lipase activity.

In this work, the effects of different carbon:nitrogen (C:N) ratios, carbon source and initial carbon concentration, in liquid medium used for submerged fermentation, on biomass growth, succinic acid production and yield of product in substrate (YP/S) were studied. It was used three carbon sources as substrate such as glucose, xylose and sucrose and the C:N ratios studied were in the range of 2.5-35. The succinic acid production was best at a C:N ratio of 12.5:1, as much for the succinic acid production as for the yield of product in relation to the substrate (YP/S). For the biomass growth the C:N ratios of 2.5:1, 5:1 and 10:1 had only presented significant difference with regards to the too much assays. The substrate that presents the best results was the glucose with succinic acid concentrations up to 7.5 g.L-1.

This study includes the synthesis of a new natural plasticizer obtained through esterification reaction of rice fatty acid and polyols, its physicochemical characterization and its preliminary application in polyvinyl chloride (PVC). Monopropylene glycol, octanol and diethylene glycol were used as polyols for esterification reaction. Catalyst Fascat ® 4100, was also added. Viscosity, acidity and hydroxyl index, moisture content, molar mass, chemical composition (by FTIR) and color were determined to characterize the natural plasticizer synthesized. The results were compared with a commercial plasticizer (DOA: di-octyl adipate) derived from petrochemical source and synthesized in laboratory. According to the results, except from color, the natural plasticizer presented similar properties of commercially available plasticizers, such as DOA. Mechanical tests indicated that the addition of the natural plasticizer to PVC films resulted in a significant increase on its elongation at break (371.2%) compared to pure PVC film, indicating a possible application for this plasticizer.

Simultaneous production of amyloglucosidase (AMG) and exo-polygalacturonase (exo-PG) was carried out by Aspergillus niger in substrate of defatted rice bran in a rotating drum bioreactor (RDB) and studied by a 31 × 22 factorial experimental design. Variables under study were A. niger strains (A. niger NRRL 3122 and A. niger t0005/007-2), types of inoculum (spore suspension and fermented bran), and types of inducer (starch, pectin, and a mix of both). Solid-state fermentation process (SSF) was conducted at 30 °C under 60-vvm aeration for 96 h in a pilot scale. Production of AMG and exo-PG was significantly affected by the fungal strain and the type of inoculum, but inducers did not trigger any significant effect, an evidence of the fact that these enzymes are constitutive. The maximum activity of exo-PG was 84 U gdm-1 whereas the maximum yield of AMG was 886.25 U gdm-1.

This study aimed at evaluating the influence of magnetic field on the growth and biomass composition of Spirulina sp., cultivated in vertical tubular photobioreactors. Magnetic fields of 5, 30 and 60mT generated by electric current and ferrite magnets were applied at different lengths of time. The magnetic field of 30 and 60mT for 1hd(-1) stimulated the growth, thus leading to higher biomass concentration by comparison with the control culture. Increase in productivity, protein and carbohydrate contents were 105.1% (60mT for 1hd(-1)), 16.6% (60mT for 24hd(-1)) and 133.2% (30mT for 24hd(-1)), respectively. These values were higher than the ones of the control. Results showed that magnetic field may influence the growth of Spirulina sp., since it triggers a stimulating effect and can leads to twofold biomass concentration in equal cultivation time periods.

The objective of this work was to study the production of GSH by Saccharomyces cerevisiae ATCC 7754 in a fermentor (5 L) using a cell recycle system with magnets. The fermentation conditions were 20°C, 500 rpm, 5% (v/v) of inoculum, pHinitial 5, 1.1 vvm aeration and total fermentation time of 72 h. The time of application of MF ranged from 24, 48 or 72 h. In comparison to the control experiment, the best results were obtained with 72 h of application of MF. The cell concentration reached 19.5 g/L and GSH concentration was 271.9 mg/L that corresponded to an increase of 2.63 and 32.1% compared to the control experiment, respectively.

The effect of magnetic fields (MF) on glutathione (GSH) production by Saccharomyces cerevisiae ATCC 7754 was studied. For this purpose, a factorial design of experiments was used to determine the influence of the time of exposure (8–16 h) and MF induction (25.0–34.3 mT), in GSH and biomass production. Additionally, control experiments (CE), without the application of MF, were performed. The results indicated the existence of favourable alterations in GSH and biomass concentrations due to the application of MF. In all experiments, the amount of biomass produced was higher than in CE and, with regard to GSH yield, in all the experiments at 24 and 48 h it was higher and in three experiments at 72 h of culture. The highest specific GSH yield (20.9 mgGSH/gbiomass), GSH yield (340.0 mg/L) and biomass (16.26 g/L) were obtained using a MF induction of 25.0 mT for 16 h. These results were 16.1%, 39.0% and 19.6% higher than in the CE, respectively. Through statistical analysis it was found that the MF induction was a significant factor in GSH yield, and also it was observed that, within the range of the experimental conditions used, the lower MF induction, the higher the GSH yield.

RESUMO A glutationa (GSH) e um tripeptideo produzido por fermentacao de Saccharomyces cerevisiae. Em virtude do custo do processo, o uso de subprodutos agroindustriais como substrato, tornase interessante. Assim, o objetivo deste estudo foi avaliar as concentracoes de extrato de levedura e soro de leite liquido para producao de GSH a partir desta levedura. Para tal, foi realizado um Delineamento Composto Central, tendo-se como resposta a concentracao de GSH produzida. As fermentacoes foram realizadas em agitador a 20 oC, 300 rpm, 5 % de inoculo (v/v), pHinicial 5, durante 96 h. Com isso foi obtido um modelo linear e os dados tratados estatisticamente por analise de variância. A maior concentracao de GSH e biomassa obtido foi 352,03 mg/L e 17,29 g/L respectivamente quando utilizado 44 g/L de extrato de levedura e 18% de soro de leite liquido, o que torna viavel o uso de soro de leite liquido como substrato em bioprocessos.