Recent Advances in the Catalytic Conversion of Methane to Methanol: From the Challenges of Traditional Catalysts to the Use of Nanomaterials and Metal-Organic Frameworks.

Methane and carbon dioxide are the main contributors to global warming, with the methane effect being 25 times more powerful than carbon dioxide. Although the sources of methane are diverse, it is a very volatile and explosive gas. One way to store the energy content of methane is through its conversion to methanol. Methanol is a liquid under ambient conditions, easy to transport, and, apart from its use as an energy source, it is a chemical platform that can serve as a starting material for the production of various higher-value products. Accordingly, the transformation of methane to methanol has been extensively studied in the literature, using traditional catalysts as different types of zeolites. However, in the last few years, a new generation of catalysts has emerged to carry out this transformation with higher conversion and selectivity, and more importantly, under mild temperature and pressure conditions. These new catalysts typically involve the use of a highly porous supporting material such as zeolite, or more recently, metal-organic frameworks (MOFs) and graphene, and metallic nanoparticles or a combination of different types of nanoparticles that are the core of the catalytic process. In this review, recent advances in the porous supports for nanoparticles used for methane oxidation to methanol under mild conditions are discussed.

Dolor local durante la administración de paracetamol endovenoso que tiene como excipiente ácido acético / Local pain during the administration of intravenous paracetamol with acetic acid as excipient

Objetivo: evaluar la presencia de dolor local durante la administración endovenosa de paracetamol con ácido acético respecto a la administración de paracetamol sin ácido acético en los pacientes intervenidos en el bloque quirúrgico.Métodos: se realizó un ensayo clínico controlado aleatorizado doble ciego de dos grupos. Se incluyeron los pacientes mayores de edad intervenidos en el bloque quirúrgico de la Fundació Salut Empordà (Girona, España) durante los meses de agosto a noviembre de 2020, que precisaron administración de paracetamol endovenoso. Se requerían 60 pacientes por grupo (paracetamol con acetato frente a paracetamol sin acetato). Se recogieron variables sociodemográficas, relativas al catéter venoso, tratamiento, presencia de dolor y momento, valoración del dolor según escala numérica verbal (0 sin dolor a 10 peor dolor imaginable). Análisis descriptivo y bivariado. Comparación de grupos según el protocolo asignado.Resultados: se incluyeron 60 pacientes en cada grupo. La media de edad fue de 56,6 años (DE=15,6), el 56,7% fue varón. Los grupos fueron homogéneos y comparables en el momento basal. Se identificó presencia de dolor en el 48,3% (n= 29) de los pacientes del grupo de infusión de paracetamol con ácido acético, mientras que en el grupo sin acetato no se dio ningún caso de dolor (p< 0,001).Conclusiones: se observaron diferencias estadísticamente significativas entre el grupo de pacientes intervenidos del bloque quirúrgico a los que se les administró paracetamol sin ácido acético, que no presentaron dolor, frente al grupo de paracetamol con ácido acético, con presencia de dolor casi en la mitad de los pacientes.(AU)

Objective: to evaluate the presence of local pain during the intravenous administration of paracetamol with acetic acid compared with the administration of paracetamol without acetic acid in patients undergoing a procedure in the surgical unit.Methods: a double-blind randomized controlled clinical trial was conducted on two groups. All patients of age who underwent a procedure in the surgical unit of the Fundació Salut Empordà (Girona, Spain) from August to November 2020 and who needed the administration of intravenous paracetamol were included in the study. Sixty (60) patients were required per group (paracetamol with acetate vs. paracetamol without acetate). Sociodemographic variables were collected, as well as those related to the venous catheter, treatment, presence and time of pain, pain assessment according to the verbal numerical scale (from 0=no pain to 10=the worst pain imaginable). Descriptive and bivariate analysis. Comparison between arms according to the assigned protocol.Results: sixty (60) patients were included in each arm. Their mean age was 56.6 years (SD =15.6), and 56.7% were male. Arms were homogeneous and comparable at baseline. The presence of pain was detected in 48.3% (n= 29) of patients in the group receiving infusion of paracetamol with acetic acid, while there were no cases of pain in the group without acetate (p< 0.001).Conclusions: statistically significant differences were observed between the group of patients undergoing procedures in the surgical unit who were administered paracetamol without acetic acid, who did not present pain, vs. the group receiving paracetamol with acetic acid, where pain was present in almost half of the patients.(AU)

Using green waste as substrate to produce biostimulant and biopesticide products through solid-state fermentation.

Although the use of green waste as a substrate in different types of microbial bioprocessing has a major impact on improving green waste valorization, very little information has been provided on this issue. The purpose of this paper is to study the feasibility of using green waste to produce a biostimulant (Indole-3-acetic acid (IAA)) and biopesticide (conidial spore) through solid-state fermentation. Trichoderma harzianum was selected as the inoculum of the process and the green waste was a mixture of grass clippings and pruning waste. An experiment was designed to study the effect of tryptophan concentration, proportion of grass and pruning waste, and substrate moisture on IAA and spore production. The results show that washing and using phosphate buffer has a beneficial effect on green waste quality in terms of bioproduction. The maximum IAA and spore productions reported in the current study were 101.46 µg g-1 dry matter and 3.03 × 109 spore g-1 dry matter, respectively. According to the results, IAA production increases with a higher amount of tryptophan and grass. However, the number of spores increased with lower amounts of tryptophan and grass. The model suggested the following optimized parameters for the production of spores and IAA: tryptophan 0.45 %, grass 61 %, and moisture 74 %. The effect of fermentation time was also studied, and the results show that the maximum IAA and spore production was obtained on days 3 and 7, respectively.

Magnetite-based nanoparticles and nanocomposites for recovery of overloaded anaerobic digesters.

The effect of magnetite nanoparticles and nanocomposites (magnetite nanoparticles impregnated into graphene oxide) supplement on the recovery of overloaded laboratory batch anaerobic reactors was assessed using two types of starting inoculum: anaerobic granular sludge (GS) and flocculent sludge (FS). Both nanomaterials recovered methane production at a dose of 0.27 g/L within 40 days in GS. Four doses of magnetite nanoparticles from 0.075 to 1 g/L recovered the process in FS systems between 30 and 50 days relaying on the dose. The presence of nanomaterials helped to reverse the effect of volatile fatty acids inhibition and enabled microbial communities to recover but also favoured the development of certain microorganisms over others. In GS reactors, the methanogenic population changed from being mostly acetoclastic (Methanothrix soehngenii) to being dominated by hydrogenotrophic species (Methanobacterium beijingense). Nanomaterial amendment may serve as a preventative measure or provide an effective remedial solution for system recovery following overloading.

Combining nanoscale zero-valent iron and anaerobic dechlorinating bacteria to degrade chlorinated methanes and 1,2-dichloroethane.

Nanoscale zero-valent iron (nZVI) has the potential to degrade a diversity of chlorinated compounds, and it is widely used for remediation of contaminated groundwaters. However, some frequently detected contaminants such as dichloromethane (DCM) and 1,2-dichloroethane (1,2-DCA) have shown nearly no reactivity with nZVI. Here, we tested the feasibility of combining anaerobic dechlorinating bacteria, Dehalobacterium and Dehalogenimonas, and nZVI as a treatment train to detoxify chlorinated methanes (i.e., chloroform-CF- and DCM), and 1,2-DCA. First, we showed that CF (500 µM) was fully degraded by 1 g/L nZVI to DCM as a major by-product, which was susceptible to fermentation by Dehalobacterium to innocuous products. Our results indicate that soluble compounds released by nZVI might cause an inhibitory impact on Dehalobacterium activity, avoiding DCM depletion. The DCM dechlorination activity was recovered when transferred to a fresh medium without nZVI. The increase in H2 production and pH was discarded as potential inhibitors. Similarly, a Dehalogenimonas-containing culture was unable to dichloroeliminate 1,2-DCA when exposed to 1 g/L nZVI, but dechlorinating activity was also recovered when transferred to nZVI-free media. The recovery of the dechlorinating activity of Dehalobacterium and Dehalogenimonas suggests that combination of nZVI and bioremediation techniques can be feasible under field conditions where dilution processes can alleviate the impact of the potential inhibitory soluble compounds.

Carbon and nitrogen optimization in solid-state fermentation for sustainable sophorolipid production using industrial waste.

The use of alternative feedstocks such as industrial or food waste is being explored for the sustainable production of sophorolipids (SLs). Microbial biosurfactants are mainly produced via submerged fermentation (SmF); however, solid-state fermentation (SSF) seems to be a promising alternative for using solid waste or byproducts that could not be exploited by SmF. Applying the advantages that SSF offers and with the aim of revalorizing industrial organic waste, the impact of carbon and nitrogen sources on the relationship between yeast growth and SL production was analyzed. The laboratory-scale system used winterization oil cake as the solid waste for a hydrophobic carbon source. Pure hydrophilic carbon (glucose) and nitrogen (urea) sources were used in a Box-Behnken statistical design of experiments at different ratios by applying the response surface methodology. Optimal conditions to maximize the production and productivity of diacetylated lactonic C18:1 were a glucose:nitrogen ratio of 181.7:1.43 (w w-1 based on the initial dry matter) at a fermentation time of 100 h, reaching 0.54 total gram of diacetylated lactonic C18:1 with a yield of 0.047 g per gram of initial dry mass. Moreover, time course fermentation under optimized conditions increased the SL crude extract and diacetylated lactonic C8:1 production by 22% and 30%, respectively, when compared to reference conditions. After optimization, industrial wastes were used to substitute pure substrates. Different industrial sludges, OFMSW hydrolysate, and sweet candy industry wastewater provided nitrogen, hydrophilic carbon, and micronutrients, respectively, allowing their use as alternative feedstocks. Sweet candy industry wastewater and cosmetic sludge are potential hydrophilic carbon and nitrogen sources, respectively, for sophorolipid production, achieving yields of approximately 70% when compared to the control group.

International air travel attitude and travel planning lead times across 45 countries in response to the COVID-19 pandemic.

This paper explores global differences in travel risk perception based on i) attitudes towards travel abroad, and ii) the time required to plan travel. Baseline data from 2019 is compared with data from 2020, the first year of the COVID-19 pandemic. A methodology based on Big Data is developed through the Skyscanner metasearch engine, working with 20,756 million flight searches and 1979 million flight picks worldwide. We conduct an exploratory analysis by region, followed by a cluster analysis of 45 countries. We argue that the findings respond to uncertainty avoidance, with clear differences between Europe, America and Asia-Pacific. This knowledge has marketing implications for tourist destinations in terms of what marketing messages to convey and the best time to introduce marketing campaigns for each country or group of countries, so that the opportunity for reactivation of tourism is maximised.

The impact of COVID-19 on European tourists' attitudes to air travel and the consequences for tourist destination evoked set formation.

We study how risk conditions derived from the COVID-19 pandemic may impact on both the desire to travel and intention to visit of tourists and, therefore, on different stages of the destination choice process. We analyse 5134 million flight searches and 379 million flight picks during 2020 for the 17 largest European tourism source markets. An unweighted index number is employed to measure the average variation for searches and picks, for the year 2020, in relation to the reference base period (year 2019). This is done for air travel in general and to Spain specifically. The study then proceeds to conduct an analysis of 17 international travel destinations that are in the evoked sets of the two largest outbound markets in Europe (Germany and UK). We also identify which markets are most favourable to Spain. The research design can inform cost-efficient marketing decisions in a situation of high uncertainty.

Postglacial range expansion of high-elevation plants is restricted by dispersal ability and habitat specialization.

Aim: Species' ecological traits influence their spatial genetic patterns. Bedrock preference strongly shapes the phylogeography of alpine plants, but its interactions with other ecological traits have rarely been disentangled. Here, we explore whether dispersal ability and degree of habitat specialization account for divergent postglacial expansion patterns of high-elevation plants in spite of similar bedrock preference. Location: The Pyrenees, southwestern Europe. Taxon: Cirsium glabrum (Asteraceae), Salix pyrenaica (Salicaceae) and Silene borderei (Caryophyllaceae). Methods: Phylogenetic, genetic structure and demographic modelling analyses based on restriction-site-associated DNA sequencing (RADseq) data from a range-wide populational sampling were conducted. Occurrence data and environmental variables were used to construct species distribution models, which were projected under current and Last Glacial Maximum conditions, and were combined with RADseq data to reconstruct the postglacial history of the study species. The degree of habitat specialization of each species was estimated based on the plant communities within which they occur, and their climatic niche breadth. Results: Salix pyrenaica, which occupies a broad range of habitats, shows a high level of range filling, a blurred genetic structure and an admixture cline between the two main genetic groups, congruent with rapid postglacial expansion. The microsite specialists C. glabrum and S. borderei exhibit a strong genetic structure and low levels of range filling, indicative of slow postglacial expansion. The good disperser C. glabrum shows higher levels of admixture between genetic groups and weaker population differentiation than the poor disperser S. borderei. Main Conclusions: Factors other than bedrock preference have a strong impact on the postglacial range dynamics of high-elevation species. Habitat specialization plays an important role, allowing species occupying a broad range of habitats to more rapidly expand their ranges after environmental change. The effect of dispersal ability is lower than expected for the study species.

Microbial biosurfactants: a review of recent environmental applications.

Microbial biosurfactants are low-molecular-weight surface-active compounds of high industrial interest owing to their chemical properties and stability under several environmental conditions. The chemistry of a biosurfactant and its production cost are defined by the selection of the producer microorganism, type of substrate, and purification strategy. Recently, biosurfactants have been applied to solve or contribute to solving some environmental problems, with this being their main field of application. The most referenced studies are based on the bioremediation of contaminated soils with recalcitrant pollutants, such as hydrocarbons or heavy metals. In the case of heavy metals, biosurfactants function as chelating agents owing to their binding capacity. However, the mechanism by which biosurfactants typically act in an environmental field is focused on their ability to reduce the surface tension, thus facilitating the emulsification and solubilization of certain pollutants (in-situ biostimulation and/or bioaugmentation). Moreover, despite the low toxicity of biosurfactants, they can also act as biocidal agents at certain doses, mainly at higher concentrations than their critical micellar concentration. More recently, biosurfactant production using alternative substrates, such as several types of organic waste and solid-state fermentation, has increased its applicability and research interest in a circular economy context. In this review, the most recent research publications on the use of biosurfactants in environmental applications as an alternative to conventional chemical surfactants are summarized and analyzed. Novel strategies using biosurfactants as agricultural and biocidal agents are also presented in this paper.

COVID-19 social distancing compliance mechanisms: UK evidence.

Non-compliance with social distancing (SD) measures clearly has negative effects on both public health and post-pandemic economic recovery. However, little is as yet known about people's views on and factors influencing their behavioral intentions toward SD measures. This study draws on moral disengagement theory and the norm-activation model to investigate mechanisms that promote or hinder compliance with SD measures. A longitudinal research approach was adopted to compare changes in the main factors over three periods of the COVID-19 pandemic in England (UK). The results reveal significant differences between the three periods regarding intentions to comply with SD measures, altruistic value, moral obligation and moral disengagement, with no significant change in ascription of responsibility. Residents showed the strongest intentions to comply with SD measures during the first national lockdown, with the highest moral obligation and lowest moral disengagement levels, compared with the lowest intention to comply during the first re-opening period. Altruistic value is important in promoting moral obligation and compliance with SD measures, whereas the predictive powers of ascription of responsibility and moral disengagement were weaker than expected. These findings offer guidance to policymakers and researchers in developing more effective policies and public communication strategies. The results suggest that communication is key to normalizing SD compliance, which can be achieved most effectively by fostering residents' altruistic value and moral considerations. Particular attention must be paid to re-opening periods between lockdowns, with clear messages to remind residents of prosocial aspects of SD compliance and public health. In addition to appropriate communication and education, technologies such as apps, QR codes and contactless shopping settings may also be used to facilitate compliance with SD measures.

Association Between the "COVID-19 Occupational Vulnerability Index" and COVID-19 Severity and Sequelae Among Hospital Employees.

OBJECTIVES: In addition to personal and health related factors, healthcare workers have an increased risk due to their work. We assessed the association of the score of the Occupational Vulnerability Index with the risk of suffering a severe COVID-19 and sequelae. METHODS: Retrospective observational study carried out in healthcare workers. Among 119 employees infected, the COVID-19 Occupational Vulnerability Index (composed of 29 items regarding personal health, working conditions, and ability to comply with preventive measures) was calculated and correlated with COVID-19 severity/sequelae. RESULTS: Workers with higher scores (six to seven points) had a significantly increased risk of developing severe disease (OR = 9.73; 95% CI, 1.53 to 35.56) and clinical sequelae (OR = 5.22; 95% CI, 1.80 to 15.16) than those with lower scores (0 to 3). CONCLUSION: The "COVID-19 Occupational Vulnerability Index" may predict the risk of severe COVID-19 disease and clinical sequelae among healthcare workers.

Sustained effect of zero-valent iron nanoparticles under semi-continuous anaerobic digestion of sewage sludge: Evolution of nanoparticles and microbial community dynamics.

The effects of adding zero-valent iron nanoparticles (nZVI) on the physicochemical, biological and biochemical responses of a semi-continuous anaerobic digestion of sewage sludge have been assessed. Two sets of consecutive experiments of 103 and 116 days, respectively, were carried out in triplicate. nZVI were magnetically retained in the reactors, and the effect of punctual doses (from 0.27 to 4.33 g L-1) over time was studied. Among the different parameters monitored, only methane content in the biogas was significantly higher when nZVI was added. However, this effect was progressively lost after the addition, and in 5-7 days, the methane content returned to initial values. The increase in the oxidation state of nanoparticles seems to be related to the loss of effect over time. Higher dose (4.33 g L-1) sustained positive effects for a longer time along with higher methane content, but this fact seems to be related to microbiome acclimation. Changes in microbial community structure could also play a role in the mechanisms involved in methane enhancement. In this sense, the microbial consortium analysis reported a shift in the balance among acetogenic eubacterial communities, and a marked increase in the relative abundance of members assigned to Methanothrix genus, recognized as acetoclastic species showing high affinity for acetate, which explain the rise in methane content in the biogas. This research demonstrates that biogas methane enrichment in semicontinuous anaerobic digesters can be achieved by using nZVI nanoparticles, thus increasing energy production or reducing costs of a later biogas upgrading process.

Valorization of agro-industrial wastes by producing 2-phenylethanol via solid-state fermentation: Influence of substrate selection on the process.

2-phenylethanol (2-PE) is a value-added compound widely used in industry due to its rose-like odor and antibacterial properties that can be bioproduced using wastes as raw materials. This study presents the valorization of nine agro-industrial wastes as potential substrates for 2-PE production using an isolated 2-PE producer Pichia kudriavzevii, and the solid-state fermentation (SSF) technology as an alternative approach. The assessed substrates comprised wastes of varied traits such that each of them provided different characteristics to the fermentation. Thus, by using a principal component analysis (PCA), it was possible to identify the most significant characteristics associated with the substrates affecting the 2-PE production. Results show that L-phenylalanine biotransformation was more efficient than de novo synthesis for producing 2-PE. Besides, from the evaluated set, the maximum 2-PE production was achieved with red apple pomace, reaching 1.7 and 25.2 mg2PE per gram of used waste through de novo and L-phenylalanine biotransformation, respectively. In that scenario, volumetric productivity and precursor yield were 39.6 mg2PE L-1h-1 and 0.69 g2PE per gram of L-phenylalanine added, respectively. From the PCA, it was identified that the reducing sugars content of the substrate, the air-filled porosity of the bed and the L-phenylalanine availability were the most critical parameters (associated with the substrates) influencing the microbial activity and 2-PE production. These results suggest that the desirable traits a solid media needs for promoting 2-PE production via SSF could be reached by using a combination of wastes in a synergistic approach.

Seed size, number and strategies in annual plants: a comparative functional analysis and synthesis.

BACKGROUND AND AIMS: Plants depend fundamentally on establishment from seed. However, protocols in trait-based ecology currently estimate seed size but not seed number. This can be rectified. For annuals, seed number should simply be a positive function of vegetative biomass and a negative function of seed size. METHODS: Using published values of comparative seed number as the 'gold standard' and a large functional database, comparative seed yield and number per plant and per m2 were predicted by multiple regression. Subsequently, ecological variation in each was explored for English and Spanish habitats, newly calculated C-S-R strategies and changed abundance in the British flora. KEY RESULTS: As predicted, comparative seed mass yield per plant was consistently a positive function of plant size and competitive ability, and largely independent of seed size. Regressions estimating comparative seed number included, additionally, seed size as a negative function. Relationships differed numerically between regions, habitats and C-S-R strategies. Moreover, some species differed in life history over their geographical range. Comparative seed yield per m2 was positively correlated with FAO crop yield, and increasing British annuals produced numerous seeds. Nevertheless, predicted values must be viewed as comparative rather than absolute: they varied according to the 'gold standard' predictor used. Moreover, regressions estimating comparative seed yield per m2 achieved low precision. CONCLUSIONS: For the first time, estimates of comparative seed yield and number for >800 annuals and their predictor equations have been produced and the ecological importance of these regenerative traits has been illustrated. 'Regenerative trait-based ecology' remains in its infancy, with work needed on determinate vs. indeterminate flowering ('bet-hedging'), C-S-R methodologies, phylogeny, comparative seed yield per m2 and changing life history. Nevertheless, this has been a positive start and readers are invited to use estimates for >800 annuals, in the Supplementary data, to help advance 'regenerative trait-based ecology' to the next level.

The use of magnetic iron oxide based nanoparticles to improve microalgae harvesting in real wastewater.

A novel approach for harvesting Scenedesmus sp. microalgae from real wastewater by using adsorbents of magnetite-based nanoparticles (Fe3O4 NPs) was tested in this study for the first time for this microalgae. Using these NPs, the harvesting efficiency was even higher than 95%. The optimal conditions (0.14 gNPs/L, a short magnetic separation time of only 8 min and 27 min of contact time) were found using the response surface methodology. The best fitting of the adsorption equilibrium results was achieved by the Langmuir isotherm model, and the maximum adsorption capacity for Scenedesmus sp. reached 3.49 g dry cell weight (DCW)/g Fe3O4 NPs. Zeta potential measurements and the Dubinin-Radushkevich isotherm model analysis pointed out that the main adsorption mechanism between Scenedesmus sp. cells and Fe3O4 NPs was electrostatic interaction. Finally, Fe3O4 NPs were six times successfully reused by combining an alkaline treatment with an ultrasonication process, which implies microalgae lysis. The results herein obtained highlight the potential for magnetic separation of microalgae from wastewater, which is capable of reaching a high harvesting efficiency in a very short time.

Promoting circular economy in the surroundings of an organic fraction of municipal solid waste anaerobic digestion treatment plant: Biogas production impact and economic factors.

The Anaerobic Digestion and Composting Plant of the Vallès Oriental Waste Treatment Centre processes source-selected organic fraction of municipal solid wastes generated in its surrounding area. To promote Circular Economy between Municipal Solid Waste and industrial waste management systems, the Treatment Centre is looking for complementary wastes to be valorised through co-digestion with its main substrate. The study includes waste characterization and a complete treatment cost analysis, that jointly with the biogas potential and the mass balance of the Plant allows to calculate the price of each waste to be treated in the Plant. Up to 13 industrial wastes have been characterised for its biogas potential and its treatment cost calculated. Treatment prices ranged between 83 and 51 € t-1.

Fed-Batch and Sequential-Batch Approaches To Enhance the Bioproduction of 2-Phenylethanol and 2-Phenethyl Acetate in Solid-State Fermentation Residue-Based Systems.

This study describes the use of alternative operational strategies in the solid-state fermentation of the agro-industrial leftover sugar cane bagasse (SCB) supplemented with l-phenylalanine, for bioproducing natural 2-phenylethanol (2-PE) and 2-phenethyl acetate (2-PEA) using K. marxianus. Here, fed-batch and sequential-batch have been assessed at two scales (1.6 and 22 L) as tools to increase the production, as well as to enhance the sustainability of this residue-based process. While in the reference batch strategy a maximum of 17 mg of 2-PE+2-PEA per gram of added SCB was reached at both scales, the implementation of fed-batch mode induced a production increase of 11.6% and 12.5%, respectively. Also, the production was increased by 16.9% and 2.4% as compared to the batch when a sequential-batch mode was used. Furthermore, the use of these strategies was accompanied by lower consumption of key resources like the inoculum, air, and time, promoting savings between 22% and 76% at both scales.

Valorisation of digestate from biowaste through solid-state fermentation to obtain value added bioproducts: A first approach.

Digestate from biowaste was assessed as a potential source of bioproducts of commercial and industrial interest through solid-state fermentation. The targeted bioproducts were hydrolytic enzymes (cellulases and proteases from autochthonous microbiome), biosurfactants (sophorolipids produced from Starmella bombicola) and biopesticides (produced from Bacillus thuringiensis). Low cellulase production was observed within the range of 0.5-1.5 FPU g-1 DM while protease production showed two discrete peaks of 66 ±â€¯8 and 65 ±â€¯3 U g-1 DM at 3.5 and 48 h, respectively. Low sophorolipids production was also obtained, with a maximum yield of 0.02 g g-1 DM using hygienised digestate supplemented with external sugar and fat sources. Biopesticides produced by B. thuringiensis were successfully at 72 h of operation, reaching a maximum spore production of 8.15 ±â€¯0.04 (107) CFU g-1 DM and 2.85 ±â€¯0.22 (107) CFU g-1 DM using sterile and hygienised digestate, respectively. These biopesticides could contribute to the substitution of chemically produced pesticides, moving towards a sustainable digestate management in a circular economy scheme.

Bioprocesses for 2-phenylethanol and 2-phenylethyl acetate production: current state and perspectives.

2-Phenylethanol (2-PE) and 2-phenethyl acetate (2-PEA) are valuable generally recognized as safe flavoring agents widely used in industry. Perfumes, pharmaceuticals, polishes, and personal care products, are some of the final products using these compounds as additives due to their rose-like odor. Also, 2-PE is used in disinfectants, pest control, and cleaning products due to its biocide capability. Although most of these additives production are derived from chemical synthesis, the current trend of consumers to prefer natural products has contributed to the development of biotechnological approaches as an alternative way to obtain natural 2-PE and 2-PEA. The most efficient route to bioproduce these compounds is through the bioconversion of L-phenylalanine via the Ehrlich pathway, and most of the advances have been focused on the development of this process. This review compiles the most recent developments in the biotechnological production of 2-PE and 2-PEA, indicating the most studied strains producing 2-PE and 2-PEA, the current advances in the in situ product recovery in liquid systems, an overview of the strain developments, and the progress in the use of residue-based systems. Future research should address the need for more sustainable and economic systems such as those using wastes as raw materials, as well as the scale-up of the proposed technologies.