Enzymatic pretreatment of microalgae using fungal broth from Trametes versicolor and commercial laccase for improved biogas production

Coupling microalgae production to wastewater treatment can reduce the costs of microalgae production for non-food bioproducts and energy consumption for wastewater treatment. Furthermore, microalgae anaerobic digestion can be enhanced by applying pretreatment techniques. The aim of this study is to improve the biogas production from microalgal biomass grown in urban wastewater treatment systems by applying an enzymatic pretreatment with crude fungal broth and commercial laccase. To this end, the fungus Trametes versicolor was cultured, and the enzymatic activity of the culture broth analysed by measuring laccase concentration. The results showed that both the fungal broth and commercial laccase pretreatment (100 U L- 1) over an exposure time of 20 min increased the methane yield in batch tests. Indeed, the fungal broth pretreatment increased the methane yield by 74%, while commercial laccase increased the methane yield by 20% as compared to non-pretreated microalgal biomass. In this manner, laccase addition enhanced microalgal biomass anaerobic biodegradability, and addition of T. versicolor broth further improved the results. This fact may be attributed to the presence of other molecules excreted by the fungus.Peer ReviewedPostprint (author's final draft

Schneiderian Membrane Thickness and Clinical Implications for Sinus Augmentation: A Systematic Review and Metaâ Regression Analyses

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141205/1/jper0888-sup-0001.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141205/2/jper0888.pd

Effect of cultivation conditions on β-estradiol removal in laboratory and pilot-plant photobioreactors by an algal-bacterial consortium treating urban wastewater

The use of microalgal consortia for urban wastewater treatment is an increasing trend, as it allows simultaneous nutrient removal and biomass production. Emerging contaminants proposed for the list of priority substances such as the hormone 17β-estradiol are commonly found in urban wastewater, and their removal using algal monocultures has been accomplished. Due to the inherent potential of algae-based systems, this study aimed to assess the capability of native photobioreactor biomass to remove 17β-estradiol under indoor and outdoor conditions. At the same time, the microbial community changes in regular and bioaugmented operations with Scenedesmus were assessed. The results show that almost complete removal (>93.75%) of the hormone 17β-estradiol can be attained in the system under favourable seasonal conditions, although these conditions greatly influence biomass concentrations and microbial diversity. Even under the harsh conditions of low temperatures and solar irradiation, the established consortium removed more than 50% of the pollutant in 24 h. While species from genus Chlorella were stable during the entire operation, the microbial diversity analysis revealed that assorted and evenly distributed populations stimulate the removal rates. Bioaugmentation assays proved that the input of additional biomass results in higher overall removal and decreases the yield per mg of biomass

Improving biogas production from microalgae by enzymatic pretreatment

In this study, enzymatic pretreatment of microalgal biomass was investigated under different conditions and evaluated using biochemical methane potential (BMP) tests. Cellulase, glucohydrolase and an enzyme mix composed of cellulase, glucohydrolase and xylanase were selected based on the microalgae cell wall composition (cellulose, hemicellulose, pectin and glycoprotein). All of them increased organic matter solubilisation, obtaining high values already after 6 h of pretreatment with an enzyme dose of 1% for cellulase and the enzyme mix. BMP tests with pretreated microalgae showed a methane yield increase of 8 and 15% for cellulase and the enzyme mix, respectively. Prospective research should evaluate enzymatic pretreatments in continuous anaerobic reactors so as to estimate the energy balance and economic cost of the process.Peer ReviewedPostprint (author's final draft

Enzymatic pretreatment of microalgae using fungal broth from Trametes versicolor and commercial laccase for improved biogas production

Es un article del grup de recerca BioremUAB (2014SGR476)Coupling microalgae production to wastewater treatment can reduce the costs of microalgae production for non-food bioproducts and energy consumption for wastewater treatment. Furthermore, microalgae anaerobic digestion can be enhanced by applying pretreatment techniques.. The aim of this study is to improve the biogas production from microalgal biomass grown in urban wastewater treatment systems by applying an enzymatic pretreatment with crude fungal broth and commercial laccase. To this end, the fungus Trametes versicolor was cultured, and the enzymatic activity of the culture broth analysed by measuring laccase concentration. The results showed that both the fungal broth and commercial laccase pretreatment (100 U/L) over an exposure time of 20 min increased the methane yield in batch tests. Indeed, the fungal broth pretreatment increased the methane yield by 74%, while commercial laccase increased the methane yield by 20% as compared to non-pretreated microalgal biomass. In this manner, laccase addition enhanced microalgal biomass anaerobic biodegradability, and addition of T. versicolor broth further improved the results. This fact may be attributed to the presence of other molecules excreted by the fungus

Degradation of pharmaceutical compounds by microalgae : photobioreactor wastewater treatment, biomass harvesting and methanization /

Premi Extraordinari de Doctorat concedit pels programes de doctorat de la UAB per curs acadèmic 2017-2018Els contaminants emergents (ECs) són un ampli grup de compostos orgànics detectats en diversos compartiments ambientals que degut a la seva presència en el medi ambient i la seva difícil degradació han aixecat un gran interès en la comunitat científica. Tot i que la seva concentració normalment està compresa entre els ng/L i els μg/L, poden representar una amenaça per a la salut humana i el medi ambient ja que són excretats per la orina i els fems, ja sigui en forma de compost actiu o com a metabòlit, ja que no són completament assimilats. D'entre tots els emergents, els compostos disruptors endocrins (EDCs) i els principis actius dels fàrmacs (PhACs) generen especial preocupació. Està àmpliament acceptat que la seva principal font d'entrada al medi ambient és a través dels efluents de les plantes depuradores (WWTP), on els tractaments convencionals de llots actius no són capaços de degradar-ne la majoria, sent capaços d'arribar a les aigües superficials, subterrànies i, posteriorment, a l'aigua potable. Per tant, s'han de buscar tractaments alternatius. Un d'aquests tractaments podria ser l'ús de les microalgues aprofitant la seva capacitat pel tractament d'aigües residuals, eliminant els nutrients de l'aigua residual i la seva posterior conversió en biocombustibles. Aquesta tesi avalua diferents aspectes relacionats amb la degradació de contaminants emergents i tractament d'aigües amb microalgues. A més de l'estudi d'un dels principals colls d'ampolla dels sistemes de microalgues, la collita, que té l'avantatge de clarificar l'aigua residual tractada i concentrar la biomassa algal per a la seva conversió a biogàs. Tant, cultius purs com efluents de microalgues s'han considerat. Primerament, s'ha estudiat la degradació individual de dos compostos estrogènics. Aquests dos compostos estrogènics s'han introduït recentment a la llista de substàncies prioritàries de la directiva de l'aigua: 17α-etinileestradiol (EE2) i 17β- estradiol (E2). La seva degradació s'ha monitoritzat a partir dels cultius purs de Chlamydomonas reinhardtii i Pseudokirchneriella subcapitata a nivell de laboratori. Per tal d'obtenir més informació sobre els mecanismes de degradació s'ha fet la identificació dels productes de transformació. A més, la degradació d'una mescla de 10 fàrmacs (9 antibiòtics i un antidepressiu) s'ha avaluat en cultius purs de microalgues a escala laboratori. S'ha realitzat la identificació dels productes de transformació de tres PhACs seleccionats. Posteriorment, un dels antibiòtics, la ciprofloxacina, s'ha analitzat. Els seus mecanismes d'eliminació han estat estudiats en sistemes algals, tant en reactors a escala laboratori com en escala pilot. Per altra banda, s'ha dissenyat un fotobioreactor (PBR) d'algues tractant aigua residual urbana i en operació durant 6 mesos. S'ha monitoritzat el seu seguiment i s'han provat diferents condicions d'operació. A més, un cop a l'estat estacionari l'eliminació de PhACs s'ha estimat i s'ha caracteritzat la població microbiana. També s'ha estudiat l'eliminació del compost estrogènic E2 en el PBR. En aquesta tesi també es remarca la importància de la collita de microalgues. Tres tècniques de collita (i.e., sedimentació natural, coagulació-floculació i la tècnica innovadora de co-pel·letització utilitzant el fong Trametes versicolor) s'han aplicat en dos efluents reals de microalgues i a una suspensió pura de Chlamydomonas reinhardtii. Finalment, s'ha dut a terme la metanització de biomassa exhausta. Abans del procés de digestió anaeròbia, per tal de solubilitzar la paret cel·lular les algues han estat sotmeses a un pretractament enzimàtic. S'han provat enzims específics i no específics, així com l'efecte combinat utilitzant una mescla d'enzims. Aquest estudi es completa amb la valorització de biomassa fúngica que prové del tractament d'efluents.Emerging contaminants (ECs) are a wide range of organic compounds detected in many environmental compartments that have raised an increasing interest in the scientific community due to their ubiquitous presence in the environment and their difficult degradation. Even though their environmental concentration is usually in the range of ng/L to μg/L, they still represent a threat to human health and environment since they are excreted with urine and faeces either as active substances or metabolites, because they are not completely assimilated. Among emerging contaminants, endocrine disrupting compounds (EDCs) and pharmaceutical active compounds (PhACs) are of major concern. It is widely accepted that the main source to the environment are the effluents of wastewater treatment plants (WWTP), where conventional activated sludge treatments are not able to degrade most of them being able to reach surface, groundwater and subsequently, drinking water. Therefore, alternative treatments should be found. One of those alternatives might be the use of microalgae by taking advantage of their capacity for wastewater treatment removing the nutrients contained in the wastewater and further microalgal biomass conversion into biofuels. The present thesis assesses different factors related to microalgal degradation of emerging contaminants and wastewater treatment. As well as the study of one of the major bottlenecks on microalgal systems, the harvesting, which has the advantage to clarify the treated wastewater and concentrate the microalgal biomass for further biogas production. Pure microalgal cultures and real microalgal effluents have been considered. First of all, individual degradation of two estrogenic compounds has been studied. The two estrogenic compounds evaluated have been recently incorporated in the priority substances in the Water Framework Directive: 17α-ethinylestradiol (EE2) and 17β- estradiol (E2). Their degradation by Chlamydomonas reinhardtii and Pseudokirchneriella subcapitata pure cultures at laboratory scale conditions has been monitored. To obtain further insights in the mechanism of degradation the transformation products have been identified. Moreover, the removal of a mixture of 10 PhACs (9 antibiotics and an antidepressant) has also been assessed in pure microalgal cultures at laboratory scale conditions. Transformation products from three chosen PhACs have been identified. One of the antibiotics, ciprofloxacin, was further evaluated. The removal mechanisms have been studied in real algal ponds in both, laboratory and pilot scale reactors. On the other hand, an algal photobioreactor (PBR) treating urban wastewater has been designed and operated during 6 months. Its performance has been monitored and different operating conditions have been tested. Furthermore, PhACs removal has been evaluated during the steady state and microbial diversity has been identified. The estrogenic compound E2 removal in the PBR has been studied. The importance of microalgal harvesting has been highlighted in the thesis. Three different harvesting techniques (i.e., natural sedimentation, coagulation-flocculation and the novel technique of co-pelletization using Trametes versicolor fungus) have been evaluated using two real microalgal effluents and a pure Chlamydomonas reinhardtii suspension. Finally, methanization of exhausted biomass has been conducted. Prior the anaerobic digestion process microalgal biomass has been submitted to an enzymatic pretreatment for its cell wall solubilisation. Specific and non-specific enzymes have been tested as well as the synergistic effects between an enzymatic mixture. The study is completed valorising fungal biomass coming from the treatment of effluents

Microalgae cultivation on wastewater digestate: β-estradiol and 17α-ethynylestradiol degradation and transformation products identification

Selenastrum capricornutum and Chlamydomonas reinhardtii were tested for possible biodegradation of the hormones β-estradiol (E2) and 17α-ethinylestradiol (EE2) when cultured in anaerobic digester centrate (ADC). Neither ADC nor the hormones had a negative or toxic effect on the microalgae growth but enhanced it. E2 and EE2 biodegradation was evaluated under different culture conditions. After 7 days of treatment, between 88% and 100% of E2 was removed by S. capricornutum. Overall, 42 and 54% of the removal was attributed to biodegradation processes, while the rest of the removal was due to adsorption onto the algae biomass. For EE2, removals between 60 and 95%, depending on the culture conditions, were achieved, with biodegradation accounting for 20-54% of the removal. E2 and EE2 were completely removed in the experiments performed with C. reinhardtii, except for EE2 in the presence of ADC, which decreased to 76%. However, C. reinhardtii presented higher adsorption percentages: 86% and 71% after 7 days for E2 and EE2, respectively. Transformation products (TPs) of E2 and EE2 generated in each treatment were also monitored. Two TPs were tentatively proposed as degradation products of E2 and EE2 by the algae. In addition, the removal of 26 endocrine disruptors and related pollutants present in the centrate was also monitored: bisphenol A was completely removed, whereas tris(2-butoxyethyl)phosphate was only removed in the absence of hormones

Performance of microalgal photobioreactor treating toilet wastewater : pharmaceutically active compound removal and biomass harvesting

In this study, a 1200L outdoor pilot scale microalgal photobioreactor (PBR) was used for toilet wastewater (WW) treatment and evaluate its ability to remove pharmaceutically active compounds (PhACs). The PBR was operated at two different hydraulic retention times (HRTs), which were 8 and 12days, during Period I (September-October) and Period II (October-December), respectively. Algal biomass concentrations varied by operating period because of seasonal changes. Nutrients (ammonia, nitrogen and total phosphorous) and chemical oxygen demand (COD) were monitored and efficiently removed in both periods (>80%), attaining the legislation limits. At the theoretical hydraulic steady state in both periods, pharmaceutical removal reached high levels (>48%). Two harvesting techniques were applied to the PBR microalgae effluent. Gravity sedimentation was efficient for biomass removal (>99% in 7min) in Period I when large particles, flocs and aggregates were present. In contrast, a longer sedimentation time was required when biomass was mainly composed of single cells (88% clarification in a 24h in Period II). The second harvesting technique investigated was the co-pelletization of algal biomass with the ligninolytic fungus Trametes versicolor, attaining >98% clarification for Period II biomass once pellets were formed. The novel technology of co-pelletization enabled the complete harvesting of single algae cells from the liquid medium in a sustainable way, which benefits the subsequent use of both biomass and the clarified effluent

Ciprofloxacin, diclofenac, ibuprofen and 17α-ethinylestradiol differentially affect the activity of acetogens and methanogens in anaerobic communities

Pharmaceutical compounds end up in wastewater treatment plants but little is known on their effect towards the different microbial groups in anaerobic communities. In this work, the effect of the antibiotic Ciprooxacin (CIP), the non-steroidal anti-inammatory drugs Diclofenac (DCF) and Ibuprofen (IBP), and the hormone 17-ethinylestradiol (EE2), on the activity of acetogens and methanogens in anaerobic communities, was investigated. Microbial communities were more affected by CIP, followed by EE2, DCF and IBP, but the response of the different microbial groups was dissimilar. For concentrations of 0.01 to 0.1 mg/L, the specic methanogenic activity was not affected. Acetogenic bacteria were sensitive to CIP concentrations above 1 mg/L, while DCF and EE2 toxicity was only detected for concentrations higher than 10 mg/L, and IBP had no effect in all concentrations tested. Acetoclastic methanogens showed higher sensitivity to the presence of these micropollutants, being affect by all the tested pharmaceutical compounds although at different degrees. Hydrogenotrophic methanogens were not affected by any concentration, indicating their lower sensitivity to these compounds when compared to acetoclasts and acetogens.e Portuguese Foundation for Science and Technology (FCT) 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. Ana Rita Silva holds a Grant from FCT, reference SFRH/BD/131905/2017info:eu-repo/semantics/publishedVersio

The severity of pandemic H1N1 influenza in the United States, from April to July 2009: A Bayesian analysis

Background: Accurate measures of the severity of pandemic (H1N1) 2009 influenza (pH1N1) are needed to assess the likely impact of an anticipated resurgence in the autumn in the Northern Hemisphere. Severity has been difficult to measure because jurisdictions with large numbers of deaths and other severe outcomes have had too many cases to assess the total number with confidence. Also, detection of severe cases may be more likely, resulting in overestimation of the severity of an average case. We sought to estimate the probabilities that symptomatic infection would lead to hospitalization, ICU admission, and death by combining data from multiple sources. Methods and Findings: We used complementary data from two US cities: Milwaukee attempted to identify cases of medically attended infection whether or not they required hospitalization, while New York City focused on the identification of hospitalizations, intensive care admission or mechanical ventilation (hereafter, ICU), and deaths. New York data were used to estimate numerators for ICU and death, and two sources of data - medically attended cases in Milwaukee or self-reported influenza-like illness (ILI) in New York - were used to estimate ratios of symptomatic cases to hospitalizations. Combining these data with estimates of the fraction detected for each level of severity, we estimated the proportion of symptomatic patients who died (symptomatic case-fatality ratio, sCFR), required ICU (sCIR), and required hospitalization (sCHR), overall and by age category. Evidence, prior information, and associated uncertainty were analyzed in a Bayesian evidence synthesis framework. Using medically attended cases and estimates of the proportion of symptomatic cases medically attended, we estimated an sCFR of 0.048% (95% credible interval [CI] 0.026%-0.096%), sCIR of 0.239% (0.134%-0.458%), and sCHR of 1.44% (0.83%-2.64%). Using self-reported ILI, we obtained estimates approximately 7-96lower. sCFR and sCIR appear to be highest in persons aged 18 y and older, and lowest in children aged 5-17 y. sCHR appears to be lowest in persons aged 5-17; our data were too sparse to allow us to determine the group in which it was the highest. Conclusions: These estimates suggest that an autumn-winter pandemic wave of pH1N1 with comparable severity per case could lead to a number of deaths in the range from considerably below that associated with seasonal influenza to slightly higher, but with the greatest impact in children aged 0-4 and adults 18-64. These estimates of impact depend on assumptions about total incidence of infection and would be larger if incidence of symptomatic infection were higher or shifted toward adults, if viral virulence increased, or if suboptimal treatment resulted from stress on the health care system; numbers would decrease if the total proportion of the population symptomatically infected were lower than assumed.published_or_final_versio