Environmental prospective of valorizing corn processing effluent to produce ferulic acid grafted chitosan polymer.

The food industry requires new production models that include more environmentally friendly waste management practices, considering that the environmental loads of solid waste and wastewater associated with this sector cause damage to the receiving ecosystems. The approach considered in this study focuses on the design and environmental assessment of an enzymatic process for the valorization of ferulic acid present in the effluent of a corn tortilla plant. The ferulic acid can be immobilized on chitosan so that the ferulic acid grafted chitosan can be used as a bioactive film with enhanced antioxidant properties with potential applications in the biotechnology sector. Its real projection approach requires the evaluation of its environmental and economic performance, trying to identify its benefits and potential in the value chain, using the Techno-Economic Analysis (TEA) as a phase for the conceptual design of the process and the Life Cycle Assessment (LCA) methodology for the environmental evaluation. It should be noted that the TEA indicators are promising, since the values of the financial indicators obtained are representative of the economic profitability, which makes the ferulic acid valorization a viable process. In terms of the environmental impact of the process, the buffer dose and the chitosan production process are identified as the main critical points. This double benefit in environmental and economic terms shows that the valorization of ferulic acid for chitosan functionalization is a promising alternative to improve the sustainability performance of corn processing.

Emerging techniques assisting nixtamalization products and by-products processing: an overview.

The production of worldwide nixtamalized products has increased in Latin American countries over the last years. For a better maize handling and exploitation of its nutritional elements, maize is subjected to a nixtamalization pretreatment protocol, which produces meaningful chemical, nutritional and quality changes in maize and its derived products, but large amounts of its primary by-product, well-known as 'nejayote', are also produced. Importantly, nejayote is usually discarded into the urbanized sewage with minimal treatment. Today, according to the recent research reports, new emerging techniques and protocols have been implemented to improve the nixtamalization products and by-products processing. New valorization approaches and biotechnological developments (including biotransformations) toward the reuse of nejayote have been developed according to its considerable content of biomolecules. Therefore, the goal of this paper is to provide a comprehensive review of the main development works at assisting nixtamalization products and by-products processing. Herein, particular attention is paid to experimental insights dealing with the valorization of nejayote.

Analyzing the phenolic enriched fractions from Nixtamalization wastewater (Nejayote) fractionated in a three-step membrane process.

Nejayote is recognized as the main by-product resulting from the nixtamalization process of maize kernels, which is categorized as an alkaline residue with a chemical composition based on carbohydrates (37.8-55.7%), fiber (22.8-25.5%), protein (4.9-7.4%), and lipids (0.4-1.5%). In addition, Nejayote has an extensive content of simple (e.g., phenolic acids) and complex phenolic compounds (e.g., anthocyanins), which are responsible for the pigmentation and antioxidant activity of maize; therefore, there is a need of their identification depending on the type of maize. The current research has focused on the efficient extraction and identification of the phenolic acids contained in Nejayote after the processing of different types of maize. The target of this work was to fractionate Nejayote from white (NWM), red (NRM), and purple maize (NPM), using three different membranes, such as microfiltration (MF with a pore size of 1 µm) and ultrafiltration (UF100 and UF1 with a molecular weight cut-off of 100 kDa and 1 kDa, respectively), which were strategically applied to extract phenolic acids while retaining other molecules. Such a membrane system exhibited a retention in the first stage of almost all carbohydrates (MF-Retentate: ca. 12-19 g GE/L), while second stage (UF100-Permeate) a concentration of phenolic components was recovered ranging from 768 to 800 mg GAE/L. Finally, in the third stage (UF1-Permeate), 14 phenolic acids were identified, including ferulic and p-coumaric acids, derived from caffeic and ferulic acids, along with other molecules (e.g., glucose and fructose).

[Capacity of the oleaginous yeast Clavispora lusitaniae Hi2 to transform agroindustrial residues into lipids]. / Potencial de la levadura oleaginosa Clavispora lusitaniae Hi2 en la conversión de residuos agroindustriales a lípidos.

BACKGROUND: Single-cell oils obtained from oleaginous microorganisms by using lignocellulosic waste hydrolysates are an alternative for producing biodiesel. AIMS: To isolate a yeast strain able to produce lipids from centrifuged nejayote (CN), hydrolyzed nejayote solids (HNS) and hydrolyzed sugarcane bagasse (HSB). METHODS: In order to identify the yeasts recovered, 26S ribosomal DNA was sequenced. The metabolic profile was assessed by using API20C AUX strips. The nutritional characterization of CN, HNS and HSB was performed by quantifying reducing sugars, total carbohydrates, starch, protein and total nitrogen. The biomass and lipid production ability were evaluated by performing growth kinetics of Clavispora lusitaniae Hi2 in combined culture media. RESULTS: Six oleaginous yeast strains were isolated and identified, selecting C. lusitaniae Hi2 to study its lipids production by using nejayote. The C. lusitaniae Hi2 strain can use glucose, xylose, arabinose, galactose and cellobiose as carbon sources. Cultures of C. lusitaniae Hi2 presented the best biomass (5.6±0.28 g/L) and lipid production (0.99±0.09 g/L) at 20 h of incubation with the CN:HNS media in the 25:75 and 50:50 ratios, respectively. CONCLUSIONS: The use of CN, HNS and HSB for the growth of C. lusitaniae Hi2 is an option to take advantage of these agro-industrial residues and generate compounds of biotechnological interest.

Combination of nejayote and swine wastewater as a medium for Arthrospira maxima and Chlorella vulgaris production and wastewater treatment.

Nejayote and swine wastewater are highly pollutant effluents and a source of organic matter load that sometimes released into water bodies (rivers or lakes), soils or public sewer system, with or without partial treatments. Nejayote is a wastewater product of alkaline cooking of maize, whereas, swine wastewater results from the primary production of pigs for the meat market. Owing to the presence of environmentally related pollutants, both sources are considered the major cause of pollution and thus require urgent action. Herein, we report a synergistic approach to effectively use and/or treat Nejayote and swine wastewater as a cost-effective culture medium for microalgae growth, which ultimately induces the removal of polluting agents. In this study, the strains Arthrospira maxima and Chlorella vulgaris were grown using different dilutions of Nejayote and swine wastewater. Both wastewaters were used as the only source of macronutrients and trace elements for growth. For A. maxima, the treatment of 10% nejayote and 90% of water (T3) resulted in a cell growth of 32 × 104 cell/mL at 12 days (µmax = 0.27/d). While, a mixture of 25% swine wastewater, 25% nejayote and 50% water (T2) produced 32 × 104 cell/mL at 18 days (µmax = 0.16/d). A significant reduction was also noted as 92% from 138 mg/L of TN, 75% from 77 mg/L of TP, and 96% from 8903 mg/L of COD, among different treatments. For C. vulgaris, the treatment of 10% swine wastewater and 90% water (T1) gave a cell growth of 128 × 106 cell/mL (µmax = 0.57/d) followed by T3 yielded 62 × 106 cell/mL (µmax = 0.70/d) and T2 yielded 48 × 106 cell/mL (µmax = 0.54/d). Up to 91% reduction from 138 mg/L of TN, 85% from 19 mg/L of TP and 96% from 4870 mg/L of COD was also recorded. These results show that microalgae can be used to treat these types of wastewater while at the same time using them as a culture media for microalgae. The resultant biomass can additionally be used for getting other sub-products of commercial interest.

Corn industrial wastewater (nejayote): a promising substrate in Mexico for methane production in a coupled system (APCR-UASB).

In Mexico, the corn tortilla is a food of great economic importance. Corn tortilla production generates about 1500-2000 m3 of wastewater per 600 tons of processed corn. Although this wastewater (also known as nejayote) has a high organic matter content, few studies in Mexico have analyzed its treatment. This study presents fresh data on the potential methane production capacity of nejayote in a two-phase anaerobic digestion system using an Anaerobic-Packed Column Reactor (APCR) to optimize the acidogenic phase and an up-flow anaerobic sludge blanket (UASB) reactor to enhance the methanogenic process. Results indicate that day 8 was ideal to couple the APCR to the UASB reactor. This allowed for a 19-day treatment that yielded 96% COD removal and generated a biogas containing 84% methane. The methane yield was 282 L kg-1 of CODremoved. Thus, two-phase anaerobic digestion is an efficient process to treat nejayote; furthermore, this study demonstrated the possibility of using an industrial application by coupling the APCR to the UASB reactor system, in order to assess its feasibility for biomethane generation as a sustainable bioenergy source.

Microencapsulation of Corn Wastewater (Nejayote) Phytochemicals by Spray Drying and Their Release Under Simulated Gastrointestinal Digestion.

Corn lime cooking generates a large amount of wastewater known as nejayote that is composed of suspended solids and solubilized phytochemicals. Spray drying can be an alternative to recover bioactive molecules, such as ferulic acid, from nejayote. Besides the yield, the physicochemical properties (solubility, water activity, pH, moisture, hygroscopicity, total phenolic content, and distribution of free and bound hydroxycinnamic acids) of spray-dried nejayote powders were analyzed. The powders were obtained at 200 °C/100 °C or 150 °C/75 °C (inlet/outlet) air temperatures with the addition of maltodextrin (MD) or 2-hydroxypropyl-beta-cyclodextrin (HBCD) as encapsulating agents. Even when no carrier agent was used, a spray-dried nejayote powder was produced. The use of MD or HBCD as carrier increased the yield from 60.26% to 68.09% or 71.83%, respectively. As expected, a high inlet temperature (200 °C) allowed a satisfactory yield (>70%) and a low powder moisture (2.5%) desired by the industry. Water activity was reduced from 0.586 to 0.307 when HBCD was used in combination with a drying inlet temperature of 150 °C; and from 0.488 to 0.280 when the inlet temperature was set at 200 °C. Around 100% bioaccessibility of the compounds was observed after in vitro digestion. The addition of HBCD increased the release time (P < 0.05). Under simulated physiological conditions, there was no reduction of total phenolics, suggesting a good stability. This paper showed the feasibility to engage the spray drying technology to the corn industry to minimize their residues and reuse their by-products.

Potencial de la levadura oleaginosa Clavispora lusitaniae Hi2 en la conversión de residuos agroindustriales a lípidos / Capacity of the oleaginous yeast Clavispora lusitaniae Hi2 to transform agroindustrial residues into lipids

AntecedentesLos lípidos obtenidos de microorganismos oleaginosos a partir de hidrolizados de residuos lignocelulósicos son una alternativa para la fabricación de biodiesel.ObjetivosAislar una levadura oleaginosa capaz de producir lípidos a partir de nejayote centrifugado (NC), hidrolizado de sólidos de nejayote (HSN) e hidrolizado de bagazo de caña de azúcar (HBC).MétodosPara identificar los aislamientos recuperados se secuenció el ADN ribosómico 26S. La capacidad metabólica se evaluó mediante tiras API20C AUX. La caracterización nutricional del NC, HSN y HBC se realizó cuantificando azúcares reductores, carbohidratos totales, almidón, proteína y nitrógeno total. La capacidad de producción de biomasa y lípidos de la cepa Clavispora lusitaniae Hi2 se evaluó mediante cinéticas de crecimiento en medios de cultivo formulados a partir de NC, HSN y HBC.ResultadosSe aislaron e identificaron seis cepas de levaduras oleaginosas, siendo C. lusitaniae Hi2 seleccionada para producir lípidos mediante el uso de nejayote. Dicha cepa puede utilizar glucosa, xilosa, arabinosa, galactosa y celobiosa como fuentes de carbono. Los cultivos de C. lusitaniae Hi2 en medio con NC y HSN (en relación 25:75) presentaron la mayor producción de biomasa, 5,6 ± 0,28 g/L; la mayor producción de lípidos, 0,99±0,09 g/L, se obtuvo con una relación 50:50 de estos residuos a las 20 h de incubación.ConclusionesLa utilización de NC, HSN y HBC para el crecimiento de C. lusitaniae Hi2 es una opción para el aprovechamiento de estos residuos y la generación de compuestos de interés biotecnológico. (AU)

BackgroundSingle-cell oils obtained from oleaginous microorganisms by using lignocellulosic waste hydrolysates are an alternative for producing biodiesel.AimsTo isolate a yeast strain able to produce lipids from centrifuged nejayote (CN), hydrolyzed nejayote solids (HNS) and hydrolyzed sugarcane bagasse (HSB).MethodsIn order to identify the yeasts recovered, 26S ribosomal DNA was sequenced. The metabolic profile was assessed by using API20C AUX strips. The nutritional characterization of CN, HNS and HSB was performed by quantifying reducing sugars, total carbohydrates, starch, protein and total nitrogen. The biomass and lipid production ability were evaluated by performing growth kinetics of Clavispora lusitaniae Hi2 in combined culture media.ResultsSix oleaginous yeast strains were isolated and identified, selecting C. lusitaniae Hi2 to study its lipids production by using nejayote. The C. lusitaniae Hi2 strain can use glucose, xylose, arabinose, galactose and cellobiose as carbon sources. Cultures of C. lusitaniae Hi2 presented the best biomass (5.6±0.28 g/L) and lipid production (0.99±0.09 g/L) at 20 h of incubation with the CN:HNS media in the 25:75 and 50:50 ratios, respectively.ConclusionsThe use of CN, HNS and HSB for the growth of C. lusitaniae Hi2 is an option to take advantage of these agro-industrial residues and generate compounds of biotechnological interest. (AU)