Polyhydroxyalkanoates from a Mixed Microbial Culture: Extraction Optimization and Polymer Characterization.

Polyhydroxyalkanoates (PHA) are biopolymers with potential to replace conventional oil-based plastics. However, PHA high production costs limit their scope of commercial applications. Downstream processing is currently the major cost factor for PHA production but one of the least investigated aspects of the PHA production chain. In this study, the extraction of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) produced at pilot scale by a mixed microbial culture was performed using sodium hydroxide (NaOH) or sodium hypochlorite (NaClO) as digestion agents of non-PHA cellular mass. Optimal conditions for digestion with NaOH (0.3 M, 4.8 h) and NaClO (9.0%, 3.4 h) resulted in polymers with a PHA purity and recovery of ca. 100%, in the case of the former and ca. 99% and 90%, respectively, in the case of the latter. These methods presented higher PHA recoveries than extraction by soxhlet with chloroform, the benchmark protocol for PHA extraction. The polymers extracted by the three methods presented similar PHA purities, molecular weights and polydispersity indices. Using the optimized conditions for NaOH and NaClO digestions, this study analyzed the effect of the initial intracellular PHA content (40-70%), biomass concentration (20-100 g/L) and biomass pre-treatment (fresh vs. dried vs. lyophilized) on the performance of PHA extraction by these two methods.

Oerskovia paurometabola can efficiently decolorize azo dye Acid Red 14 and remove its recalcitrant metabolite.

The biodegradation of dyes remains one of the biggest challenges of textile wastewater. Azo dyes are one of the most commonly employed dye classes, and biological treatment processes tend to generate recalcitrant aromatic amines, which are more toxic than the parent dye molecule. This study aimed to isolate bacterial strains with the capacity to degrade both the azo dye and the resulting aromatic amines towards the development of a simple and reliable treatment approach for dye-laden wastewaters. A mixed bacterial enrichment was first developed in an anaerobic-aerobic lab-scale sequencing batch reactor (SBR) fed with a synthetic textile wastewater containing the model textile azo dye Acid Red 14 (AR14). Eighteen bacterial strains were isolated from the SBR, including members of the Acinetobacter, Pseudomonas and Oerskovia genera, Oerskovia paurometabola presenting the highest decolorization capacity (91% after 24 h in static anaerobic culture). Growth assays supported that this is a facultative bacterium, and decolorization batch tests with 20-100 mg AR14 L-1 in a synthetic textile wastewater supplemented with yeast extract indicated that O. paurometabola has a high color removal capacity for a significant range of AR14 concentrations. In addition, a model typically used to describe biodegradation of xenobiotic compounds was adjusted to the results, to predict AR14 biodegradation time profiles at different initial concentrations. HPLC analysis confirmed that decolorization occurred through azo bond reduction under anaerobic conditions, the azo dye being completely reduced after 24 h of anaerobic incubation for the range of concentrations tested. Interestingly, partial (up to 63%) removal of one of the resulting aromatic amines (4-amino-naphthalene-1-sulfonic acid) was observed when subsequently subjected to aerobic conditions. Overall, this work showed the azo dye biodegradation potential of specific bacterial strains isolated from mixed culture bioreactors, reporting for the first time the decolorization capacity of an Oerskovia sp. with further biodegradation of a recalcitrant sulfonated aromatic amine metabolite.

Stability of aerobic granules during long-term bioreactor operation.

Aerobic granular sludge technology has been extensively studied over the past 20 years and is regarded as the upcoming new standard for biological treatment of domestic and industrial wastewaters. Aerobic granules (AG) are dense, compact, self-immobilized microbial aggregates that allow better sludge-water separation and thereby higher biomass concentrations in the bioreactor than conventional activated sludge aggregates. This brings potential practical advantages in terms of investment cost, energy consumption and footprint. Yet, despite the relevant advances regarding the process of AG formation, instability of AG during long-term operation is still seen as a major barrier for a broad practical application of this technology. This paper presents an up-to-date review of the literature focusing on AG stability, aiming to contribute to the identification of key factors for promoting long-term stability of AG and to a better understanding of the underlying mechanisms. Operational conditions leading to AG disintegration are described, including high organic loads, particulate substrates in the influent, toxic feed components, aerobic feeding and too short famine periods. These operational and influent wastewater composition conditions were shown to influence the micro-environment of AG, consequently affecting their stability. Granule stability is generally favored by the presence of a dense core, with microbial growth throughout the AG depth being a crucial intrinsic factor determining its structural integrity. Accordingly, possible practical solutions to improve granule long-term stability are described, namely through the promotion of minimal substrate concentration gradients and control of microbial growth rates within AG, including anaerobic, plug-flow feeding and specific sludge removal strategies.

Effect of an azo dye on the performance of an aerobic granular sludge sequencing batch reactor treating a simulated textile wastewater.

This study analyzed the effect of an azo dye (Acid Red 14) on the performance of an aerobic granular sludge (AGS) sequencing batch reactor (SBR) system operated with 6-h anaerobic-aerobic cycles for the treatment of a synthetic textile wastewater. In this sense, two SBRs inoculated with AGS from a domestic wastewater treatment plant were run in parallel, being one supplied with the dye and the other used as a dye-free control. The AGS successfully adapted to the new hydrodynamic conditions forming smaller, denser granules in both reactors, with optimal sludge volume index values of 19 and 17 mL g(-1) after 5-min and 30-min settling, respectively. As a result, high biomass concentration levels and sludge age values were registered, up to 13 gTSS L(-1) and 40 days, respectively, when deliberate biomass wastage was limited to the sampling needs. Stable dye removal yields above 90% were attained during the anaerobic reaction phase, confirmed by the formation of one of the aromatic amines arising from azo bond reduction. The control of the sludge retention time (SRT) to 15 days triggered a 30% reduction in the biodecolorization yield. However, the increase of the SRT values back to levels above 25 days reverted this effect and also promoted the complete bioconversion of the identified aromatic amine during the aerobic reaction phase. The dye and its breakdown products did not negatively affect the treatment performance, as organic load removal yields higher than 80% were attained in both reactors, up to 77% occurring in the anaerobic phase. These high anaerobic organic removal levels were correlated to an increase of Defluviicoccus-related glycogen accumulating organisms in the biomass. Also, the capacity of the system to deal with shocks of high dye concentration and organic load was successfully demonstrated. Granule breakup after long-term operation only occurred in the dye-free control SBR, suggesting that the azo dye plays an important role in improving granule stability. Fluorescence in situ hybridization (FISH) analysis confirmed the compact structure of the dye-fed granules, microbial activity being apparently maintained in the granule core, as opposed to the dye-free control. These findings support the potential application of the AGS technology for textile wastewater treatment.

Hepatobiliary abnormalities in pediatric patients with sickle cell disease.

OBJECTIVE: to describe clinical, laboratory and ultrasonographic abnormalities in the hepatobiliary system of pediatric patients with sickle cell disease in the city of Salvador, Brazil. MATERIAL AND METHODS: pediatric patients with sickle cell disease were clinically evaluated, their charts were reviewed and findings of supplementary tests were examined to identify hepatobiliary abnormalities. RESULTS: a total of 134 patients were evaluated, 65 of whom (48.9%) presented hepatomegalia. Elevated transaminases were present in 42.2% and 11.4% presented cholelithiasis. There was a statistically significant association between the presence of hepatomegalia and SS homozygotes and between cholelithiasis and patients over 10 years of age (p = 0.01 and p = 0.00, respectively). CONCLUSION: hepatobiliary abnormalities in patients with sickle cell disease were common, particularly in patients with hemoglobin SS and in adolescent patients.

Frequency of celiac disease and its serological markers in patients with autoimmune hepatitis

Transglutaminase (anti-tTG) and anti-endomysial (AEA) antibodies were reported to occur in patients with autoimmune hepatitis (AIH) as well as in subjects with advanced cirrhosis, but the prevalence of celiac disease (CD) in patients with AIH is either negligible or unknown. The frequency of IgA anti-tTG and IgA AEA was determined in 64 patients (54 females, mean age 19[5-67] years ) with AIH diagnosed according to international criteria. Patients with positive or intermediate results for those antibodies were submitted to duodenal biopsy and HLA-DQ2 or DQ8 typing. Anti-tTG and AEA were detected in 6 (9 por cento) and one patient (1.6 por cento) with AIH, respectively. Positive and borderline results for IgA anti-tTG were detected, respectively, in two (3 por cento) and four (6 por cento) patients. Only one patient with HLA-DQ2 and IgA anti-tTG and IgA AEA had CD on duodenal biopsy. Two patients with either positive or borderline results for IgA anti-tTG antibody and HLA-DQ2 had normal histology on duodenal biopsy. IgA anti-tTG antibody and/or AEA were observed in 9% of AIH patients, but CD was confirmed in only one of them. The occurrence of IgA anti-tTG antibody in the other patients could be ascribed to the presence of chronic liver disease or to latent or potential CD.

Manifestações auto-imunes associadas com hepatite auto-imune / Concurrent autommune manifestations in patients with AIH

Pacientes com hepatite auto-imune (HAI) apresentam diversas manifestações de auto-imunidade associadas e, muitas vezes, desenvolvem doenças auto-imunes que necessitam de reconhecimento precoce. Este trabalho tem por objetivo descrever a freqüência de manifestações auto-imunes em portadores de Hepatite auto-imune. Estudo descritivo de série de casos foi realizado na cidade de Salvador, Bahia, no qual foram selecionados por conveniência 69 pacientes, entre adultos e crianças com diagnóstico prévio de hepatite auto-imune, com o objetivo de avaliar a freqüência de manifestações auto-imunes associadas nesses pacientes. Os participantes do estudo foram entrevistados quanto à presença de manifestação auto-imune associada ao quadro de hepatite, e, em seguida, avaliaram-se os prontuários para obtenção dos exames que confirmassem o referido diagnóstico de outra manifestação auto-imune. A freqüência das manifestações auto-imunes associadas foi de 23,2 por cento, e a artrite foi a manifestação auto-imune mais freqüente (8,7 por cento), seguida de diabetes mellitus tipo 1 (4,3 por cento). A retocolite ulcerativa e a colangite esclerosante primária foram igualmente freqüentes, ocorrendo em 2,9 por cento dos pacientes. As outras manifestações auto-imunes associadas obtiveram uma freqüência de 1,4 por cento para cada uma delas. Concluiu-se que a ocorrência de manifestações auto-imunes é freqüente e ocorre de forma variada nos pacientes com HAI. Assim, o reconhecimento precoce dessas condições auto-imunes associadas é fundamental para a realização de medidas terapêuticas específicas, evitando-se as possíveis complicações.

Alterações hepáticas na doença celíaca / Liver dysfunction in coeliac disease

O envolvimento do fígado tem sido freqüentemente descrito em pacientes celíacos. Condições como hipertransaminasemia, que retorna a valores normais após a dieta isenta de glúten, doenças hepáticas de origem auto-imune e outras doenças crônicas do fígado, sobretudo a hepatite crônica pelo vírus C, estão associadas com a doença celíaca. O objetivo deste artigo é discutir as relações recentemente evidenciadas na literatura entre essa enteropatia glúten-sensível e os tipos de alterações hepáticas.

Pediatric knowledge about acute viral hepatitis.

Knowledge about hepatotropic viruses is crucial for pediatricians because of the high prevalence of viral hepatitis during childhood. The multiplicity of hepatotropic viruses, the spectrum of acute and chronic infections, and the sequels of viral hepatitis result in a need for physicians to better understand the clinical and epidemiological context of patients with viral hepatitis, as well as the importance of prevention measures for hepatitis. A descriptive cross-sectional study was made of pediatrician's knowledge about viral hepatitis, through questionnaires to 574 pediatricians, with no obligation of identification. The pediatricians were recruited among those who attended a national Congress of Pediatrics in Brasília, Brazil. Among these pediatricians, 50.1% frequently treated cases of hepatitis, and 74.7% indicated that they had knowledge of the existence of five hepatotropic viruses; 14.5% knew about at least four types of hepatitis complications, while only 7.7% and 4.3% were able to correctly diagnose viral hepatitis A and B, respectively. Many (28.4%) did not know how to treat the patients adequately. Only 37.5% had already recommended vaccination against hepatitis B. Only 50.2% of the pediatricians had been vaccinated against hepatitis B. We concluded that it is crucial to make pediatricians more knowledgeable about viral hepatitis, through continued education programs, especially emphasizing prevention procedures.

Pediatric knowledge about acute viral hepatitis

Knowledge about hepatotropic viruses is crucial for pediatricians because of the high prevalence of viral hepatitis during childhood. The multiplicity of hepatotropic viruses, the spectrum of acute and chronic infections, and the sequels of viral hepatitis result in a need for physicians to better understand the clinical and epidemiological context of patients with viral hepatitis, as well as the importance of prevention measures for hepatitis. A descriptive cross-sectional study was made of pediatrician's knowledge about viral hepatitis, through questionnaires to 574 pediatricians, with no obligation of identification. The pediatricians were recruited among those who attended a national Congress of Pediatrics in Brasília, Brazil. Among these pediatricians, 50.1 percent frequently treated cases of hepatitis, and 74.7 percent indicated that they had knowledge of the existence of five hepatotropic viruses; 14.5 percent knew about at least four types of hepatitis complications, while only 7.7 percent and 4.3 percent were able to correctly diagnose viral hepatitis A and B, respectively. Many (28.4 percent) did not know how to treat the patients adequately. Only 37.5 percent had already recommended vaccination against hepatitis B. Only 50.2 percent of the pediatricians had been vaccinated against hepatitis B. We concluded that it is crucial to make pediatricians more knowledgeable about viral hepatitis, through continued education programs, especially emphasizing prevention procedures.

Comparação do diagnóstico endoscópico com o histopatológico em crianças portadoras de esofagite / Endoscopic diagnosis versus histologic diagnosis in children with esophagitis

O refluxo gastroesofágico representa o fluxo retrógrado do conteúdo gástrico para o esôfago. A doença do refluxo gastroesofágico é a condição na qual estão presentes sintomas e/ou complicações digestivas, dentre elas a esofagite. O diagnóstico da esofagite é realizado através da endoscopia digestiva alta (EDA) e do exame histopatológico da mucosa esofágica. O presente estudo teve como objetivo comparar os achados endoscópicos e histopatológicos da região esofágica em crianças portadoras de esofagite. Foram revisados resultados de EDA e de biópsias de 125 crianças com idade entre 0 a 18 anos com esofagite, no período de 1997 a 2001. Destes pacientes, 69 (52,20 por cento) eram do sexo feminino. Nos resultados endoscópicos, 104 (83,20 por cento) pacientes tiveram o diagnóstico de esofagite edematosa; na histologia, 48 (33,40 por cento) das crianças apresentaram esofagite crônica, enquanto na de 29 (23,20 por cento) não ocorreram alterações. Quando correlacionados à histopatologia, os resultados da EDA não são fidedignos a ponto de justificar-se o uso isolado desta. É fundamental a realização da biópsia para esclarecimento diagnóstico desta patologia e para acompanhamento dos pacientes. Há ainda a necessidade de múltiplas biópsias para análise adequada do processo e para identificação precoce do esôfago de Barrett.