Successive fermentation of aguamiel and molasses by Aspergillus oryzae and Saccharomyces cerevisiae to obtain high purity fructooligosaccharides

Fructooligosaccharides (FOS) are usually synthesized with pure enzymes using highly concentrated sucrose solutions. In this work, low-cost aguamiel and molasses were explored as sucrose alternatives to produce FOS, via whole-cell fermentation, with an Aspergillus oryzae DIA-MF strain. FOS production process was optimized through a central composite experimental design, with two independent variables: initial sucrose concentration in a medium composed of aguamiel and molasses (AgMe), and inoculum concentration. The optimized process—165 g/L initial sucrose in AgMe (adjusted with concentrated molasses) and 1 × 107 spores/mL inoculum concentration—resulted in an FOS production of 119 ± 12 g/L and a yield of 0.64 ± 0.05 g FOS/g GFi. Among the FOSs produced were kestose, nystose, 1-fructofuranosyl-nystose, and potentially a novel trisaccharide produced by this strain. To reduce the content of mono- and disaccharides in the mixture, run a successive fermentation was run with two Saccharomyces cerevisiae strains. Fermentations run with S. cerevisiae S227 improved FOS purity in the mixture from 39 ± 3% to 61.0 ± 0.6% (w/w) after 16 h of fermentation. This study showed that agro-industrial wastes such as molasses with aguamiel are excellent alternatives as substrate sources for the production of prebiotic FOS, resulting in a lower-cost process.Orlando de la Rosa acknowledges the National Council of Science and Technology (CONACYT-Mexico) for the financial support given through the PBM (Program Becas Mixtas) (CVU 860996) and the APC was funded by Universidad Autónoma de Coahuila (Mexico). The study was also supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit and the Project ColOsH PTDC/BTM-SAL/30071/2017 (POCI-01-0145-FEDER-030071).info:eu-repo/semantics/publishedVersio

Fructosyltransferase Sources, Production, and Applications for Prebiotics Production

Fructooligosaccharides (FOS) are considered prebiotic compounds and are found in different vegetables and fruits but at low concentrations. FOS are produced by enzymatic transformation of sucrose using fructosyltransferase (FTase). Development of new production methods and search for FTase with high activity and stability for FOS production Is an actual research topic. In this article is discussed the most recent advances on FTase and its applications. Different microorganisms have been tested under various fermentation systems in order to identify and characterize new genes codifying for FTase. Some of these genes have been isolated from bacteria, fungi, and plants, with a wide range of percentages of identity but retaining the eight highly conserved motifs of the hydrolase family 32 glycoside. Therefore, this article presents an overview of the most recent advances on FTase and its applications

Bioreactor design for enzymatic hydrolysis of biomass under the biorefinery concept

The dependence on non-renewable resources, particularly fossil fuels, has awaken a growing interest in research of sustainable alternative energy sources, such as bioethanol. The production of bioethanol from lignocellulosic materials comprises three main stages, starting with a pretreatment, followed by an enzymatic hydrolysis step where fermentable sugars are obtained for the final fermentation process. Enzymatic hydrolysis represents an essential step in the bioethanol production, however there are some limitations in it that hinders the process to be economically feasible. Different strategies have been studied to overcome these limitations, including the enzyme recycling and the utilization of high solids concentrations. Several investigations have been carried out in different bioreactor configurations with the aim to obtain higher yields of glucose in the enzymatic hydrolysis stage; however, the commonest are Stirred Tank Bioreactors (STBR) and Membrane Bioreactors (MBR). In general, the key criteria for a bioreactor design include adequate mass transfer, low shear stress, and efficient mixing that allows the appropriated interaction between the substrate and the enzyme. Therefore, this review will address the main aspects to be considered for a bioreactor design, as well as, the operational conditions, some characteristics and mode of operating strategies of the two main bioreactors used in the enzymatic hydrolysis stage. Moreover, two types of pneumatically agitated bioreactors, namely bubble column and gas-lift bioreactors, are discussed as promising alternatives to develop enzymatic saccharification due to their low energy consumption compared with STBR.This work was financial supported by the Secretary of Public Education of Mexico – Mexican Science and Technology Council (SEPCONACYT) with the Basic Science Project-2015-01 (Ref. 254808), and the Energy Sustainability Fund 2014-05 (CONACYT-SENER), Mexican Centre for Innovation in Bioenergy (Cemie-Bio), and Cluster of Bioalcohols (Ref. 249564). The author Marcela Pino also thanks the National Council for Science and Technology (CONACYT, Mexico) for her Master Fellowship support (grant number: 611312/452636).info:eu-repo/semantics/publishedVersio

Production of an Enzymatic Extract From Aspergillus oryzae DIA-MF to Improve the Fructooligosaccharides Profile of Aguamiel

Aguamiel is a natural sap produced by some species of agave plants, such as Agave salmiana, A. atrovirens, or A. angustifolia. It is a product with a high concentration of fructose, glucose or sucrose, although its composition may vary depending on the season in which it is produced, and may also contain agave fructans (or agavins) or fructooligosaccharides (FOS). It has been reported that FOS can be produced by enzymes that act on sucrose or inulin, transfructosylating or hydrolyzing these materials, respectively. Due to the sugar content in aguamiel, the application of an enzymatic complex produced by Aspergillus oryzae DIA MF was carried out. This complex was characterized by 1-D electrophoresis SDS-PAGE, and its transfructosylation and hydrolysis activities were determined by HPLC. In order to determine the conditions at which the concentration of FOS in this beverage increased, kinetics were carried out at different temperatures (30, 50, and 70°C) and times (0, 1, 2, 3, 4, 5, 10, and 15 h). Finally, the antioxidant and prebiotic activities were evaluated. FOS concentration in aguamiel was increased from 1.61 ± 0.08 to 31.01 ± 3.42 g/ L after 10 h reaction at 30°C applying 10% enzymatic fraction-substrate (v/v). Antioxidant activity was highly increased (34.81–116.46 mg/eq Trolox in DPPH assay and 42.65 to 298.86 mg/eq Trolox in FRAP assay) and growth of probiotic bacteria was higher in aguamiel after the enzymatic treatment. In conclusion, after the application of the enzymatic treatment, aguamiel was enriched with FOS which improved antioxidant and prebiotic properties, so it can be used as a functional food

Fructooligosaccharides production from agro-wastes as alternative low-cost source

Background The prebiotic properties of fructooligosaccharides (FOS) are well documented. The high demand of functional food by the food, pharmaceutical and biotechnology industries have lead researchers to explore new and more feasible processes to produce FOS. Not only economical substrates are being exploited to reduce costs, but also, seeking to attend a global problem, the excessive generation of agro-industrial wastes that are polluting the earth, which are not being completely exploited, have been a concern. Scope and approach The purpose of this review is to present a concise (but wide-ranging) appraisal on the latest advances in fructooligosaccharides production from agro-wastes, as alternative low-cost source. Emphasis is placed on the examination, analysis and discussion of the prospects for using different agro-industrial waste bioresources for the production of FOS and FOS-producing enzymes. Key findings and conclusions The food, agro-industrial and forestry industries generate large volumes of waste, that are mainly composed of complex carbohydrates and crude proteins, that can be useful as nutrients for microbial growth, and enzymes or other metabolites production. Agro-industrial wastes are discarded, and its accumulation generates a severe environmental impact. The development of value-added processes using agro-industrial wastes is very attractive and becomes an environmentally friendly waste management method.Authors thank to National Council of Science and Technology (CONACYT, México) for the financial support (CVU 860996) given to the Master Program in Food Science and Technology offered by the Autonomous University of Coahuila, Mexico. This study was also supported by the Portuguese Foundation for Science and Technology under the scope of the strategic funding of UID/BIO/04469/2019 unit and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte also, Project ColOsH02/SAICT/2017(POCI-01-0145-FEDER-030071).info:eu-repo/semantics/publishedVersio

Biotechnological Approach for the Production of Prebiotics and Search for New Probiotics and their Application in the Food Industry

Background and objective: Prebiotics and probiotics intake have been widely recognized in past recent years due to possessing multiple health benefits. Prebiotics are non-digestible carbohydrates that promote the growth and/or activity of beneficial bacteria in the colon which improves the health. Moreover, the incorporation of probiotics in food has also been a growing practice due to its immunomodulatory effect, the production of organic acids and other compounds that promotes the absorption of nutrients and the general health of the digestive system.Results and conclusion: Biotechnological strategies have been proposed for prebiotic production and purification in order to meet the demand to be included as ingredients in functional food formulation. Different aspects related to the substrates and different fermentation systems for their production as well as the purification and characterization processes are addressed. Also, we will present the benefits promoted by probiotics, the methods of isolation and characterization, as well as the evaluation of these attributes, so that they can be used in the food industry. With the technological developments in prebiotics and probiotics, it will be possible to deliver foods that respond to consumer demand with low cost and with pleasant sensory characteristics as well as providing beneficial health effects.Conflict of interest: The authors declare no conflict of interest

Polyembryony in Maize: A Complex, Elusive, and Potentially Agronomical Useful Trait

Polyembryony (PE) is a rare phenomenon in cultivated plant species. Since nineteenth century, several reports have been published on PE in maize. Reports of multiple seedlings developing at embryonic level in laboratory and studies under greenhouse and field conditions have demonstrated the presence of PE in cultivated maize (Zea mays L.). Nevertheless, there is a lack of knowledge about this phenomenon; diverse genetic mechanisms controlling PE in maize have been proposed: Mendelian inheritance of a single gene, interaction between two genes and multiple genes are some of the proposed mechanisms. On the other hand, the presence of two or more embryos per seed confers higher nutrimental quality because these grains have more crude fat and lysine than normal maize kernels. As mentioned above, there is a necessity for more studies about PE maize in order to establish the genetic mechanism responsible for this phenomenon; on the other hand, previous studies showed that PE has potential to generate specialized maize varieties with yield potential and grain quality

Synthesis of BiOI/Mordenite Composites for Photocatalytic Treatment of Organic Pollutants Present in Agro-Industrial Wastewater

Recently, bismuth oxyiodide (BiOI) is an attractive semiconductor to use in heterogeneous photocatalysis processes. Unfortunately, BiOI individually shows limited photocatalytic efficiency, instability, and a quick recombination of electron/holes. Considering the practical application of this semiconductor, some studies show that synthetic zeolites provide good support for this photocatalyst. This support material permits a better photocatalytic efficiency because it prevents the quick recombination of photogenerated pairs. However, the optimal conditions (time and temperature) to obtain composites (BiOI/ synthetic zeolite) with high photocatalytic efficiency using a coprecipitation-solvothermal growth method have not yet been reported. In this study, a response surface methodology (RSM) based on a central composite design (CCD) was applied to optimize the synthesis conditions of BiOI/mordenite composites. For this purpose, eleven BiOI/mordenite composites were synthesized using a combined coprecipitation-solvothermal method under different time and temperature conditions. The photocatalytic activities of the synthesized composites were evaluated after 20 min of photocatalytic oxidation of caffeic acid, a typical organic pollutant found in agro-industrial wastewater. Moreover, BiOI/mordenite composites with the highest and lowest photocatalytic activity were physically and chemically characterized using nitrogen adsorption isotherms, scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and diffuse reflectance spectroscopy (DRS). The optimal synthesis conditions prove to be 187 °C and 9 h. In addition, the changes applied to the experimental conditions led to surface property modifications that influenced the photocatalytic degradation efficiency of the BiOI/mordenite composite toward caffeic acid photodegradation

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat