Microbial processes and bacterial populations associated to anaerobic treatment of sulfate-rich wastewater

A pilot-scale (1.2 m3) anaerobic sequencing batch biofilm reactor (ASBBR) containing mineral coal for biomass attachment was fed with sulfate-rich wastewater at increasing sulfate concentrations. Ethanol was used as the main organic source. Tested COD/sulfate ratios were of 1.8 and 1.5 for sulfate loading rates of 0.65–1.90 kgSO42−/cycle (48 h-cycle) or of 1.0 in the trial with 3.0 gSO42− l−1. Sulfate removal efficiencies observed in all trials were as high as 99%. Molecular inventories indicated a shift on the microbial composition and a decrease on species diversity with the increase of sulfate concentration. Beta-proteobacteria species affiliated with Aminomonas spp. and Thermanaerovibrio spp. predominated at 1.0 gSO42− l−1. At higher sulfate concentrations the predominant bacterial group was Delta-proteobacteria mainly Desulfovibrio spp. and Desulfomicrobium spp. at 2.0 gSO42− l−1, whereas Desulfurella spp. and Coprothermobacter spp. predominated at 3.0 gSO42− l−1. These organisms have been commonly associated with sulfate reduction producing acetate, sulfide and sulfur. Methanogenic archaea (Methanosaeta spp.) was found at 1.0 and 2.0 gSO42− l−1. Additionally, a simplified mathematical model was used to infer on metabolic pathways of the biomass involved in sulfate reduction

Biotecnologia: o desafio da transdisciplinaridade

Biotecnologia: o desafio da transdisciplinaridade O Instituto de Ciências da Saúde da Universidade Federal da Bahia tem contribuído para a formação de um significativo número de Bacharéis em Biotecnologia. Esses profissionais são preparados para contribuir com o desenvolvimento de processos industriais, ambientais e/ou médico-farmacêuticos. Essa flexibilidade profissional só é possível porque a biotecnologia é muito mais “integrativa” do que de especialização do conhecimento, uma vez que se trata de uma ciência que deve integrar os conhecimentos das engenharias, biologia, química e matemática e, por isso, exige que o profissional formado seja competente em articular o conteúdo dessas diferentes fontes de informação. Por ser um trabalho complexo e, talvez, infindável, o profissional não pode se apoiar apenas no acúmulo e na memorização de informação. A frase que poderia ser melhor utilizada para descrever esse caso seria que “o Biotecnólogo tem que ser capaz de transitar por entre as diferentes áreas do conhecimento”. A “transdisciplinaridade” é, portanto, uma função pensante utilizada para unir o conteúdo das várias disciplinas e assim originar uma nova interpretação da realidade. Vários profissionais se preocupam com os conhecimentos específicos oferecidos nas disciplinas dos mais de quarenta cursos de Biotecnologia espalhados pelo país. No entanto, as atividades de um Bacharel em Biotecnologia são mais complexas do que o uso da linguagem, memória técnica e do raciocínio lógico. A habilidade de articular o conteúdo cognitivo de forma a integrar as diferentes áreas do conhecimento envolve o desenvolvimento da curiosidade e da flexibilidade emocional e intelectual. Com certeza, todas essas funções podem ser adquiridas através de técnicas de aprendizagem, daí porque na concepção dos cursos são idealizadas disciplinas ou atividades na grade curricular para facilitar esse tipo de abordagem. Por esse motivo, os professores e os seus métodos de ensino acabam sendo de extrema importância para fomentar esse tipo de formação “integradora”. O corpo docente do curso de Biotecnologia do Instituto de Ciências da Saúde está consciente desse fato e objetiva esse tipo de abordagem na atividade de ensino. Portanto, para fazer uma descrição é possível adotar uma visão mais pragmática do que acadêmica desse fato......

Effect of sulfate on low-temperature anaerobic digestion

The effect of sulfate addition on the stability of, and microbial community behavior in, low-temperature anaerobic expanded granular sludge bed-based bioreactors was investigated at 15°C. Efficient bioreactor performance was observed, with chemical oxygen demand (COD) removal efficiencies of >90%, and a mean SO2−4 removal rate of 98.3%. In situ methanogensis appeared unaffected at a COD: SO2−4 influent ratio of 8:1, and subsequently of 3:1, and was impacted marginally only when the COD: SO2−4 ratio was 1:2. Specific methanogenic activity assays indicated a complex set of interactions between sulfate-reducing bacteria (SRB), methanogens and homoacetogenic bacteria. SO2−4 addition resulted in predominantly acetoclastic, rather than hydrogenotrophic, methanogenesis until >600 days of SO2−4-influenced bioreactor operation. Temporal microbial community development was monitored by denaturation gradient gel electrophoresis (DGGE) of 16S rRNA genes. Fluorescence in situ hybridizations (FISH), qPCR and microsensor analysis were combined to investigate the distribution of microbial groups, and particularly SRB and methanogens, along the structure of granular biofilms. qPCR data indicated that sulfidogenic genes were present in methanogenic and sulfidogenic biofilms, indicating the potential for sulfate reduction even in bioreactors not exposed to SO2−4. Although the architecture of methanogenic and sulfidogenic granules was similar, indicating the presence of SRB even in methanogenic systems, FISH with rRNA targets found that the SRB were more abundant in the sulfidogenic biofilms. Methanosaeta species were the predominant, keystone members of the archaeal community, with the complete absence of the Methanosarcina species in the experimental bioreactor by trial conclusion. Microsensor data suggested the ordered distribution of sulfate reduction and sulfide accumulation, even in methanogenic granules

Quantifying the inovation of cosmetic formulations that contains phenolic rich fruit extracts as fotoprotective bioactives

Introduction: sunscreen is a cosmetic used to protect human skin from the deleterious effects of UV radiation and thus minimize the risks of developing skin cancer. Extracts produced from fruits, such as Abiu, Guava, Rambutan and Grape, have significant concentrations of chromophores and phenolic substances that have the ability to absorb UV light and neutralize free radicals. The production of cosmetics from naturally occurring substances with such activities will be of great importance for Brazilian industry and could reduce the cost of production, given the large existing biodiversity in the country. Objectives: carry out a patent search for formulations and cosmetic products that contains phenolic rich fruit extracts as photoprotective and antioxidant bioactives. Methodology: a survey of patents was carried out in the database of the National Institute of Intellectual Property (INPI) and the European Patent Office (EPO), covering a time period between 2008 and 2018, using a combination of keywords related to herbal cosmetics and sunscreens. Results: this research identifies a significant number of patents related to plant extract in association with sunscreen product, however, no patent filings were identified for cosmetic products containing extracts of the evaluated fruits, either alone or in combination, for photoprotective and antioxidant purposes. Conclusion: the Brazilian and international market for sun care products moves millions to billions of dollars annually and have a significant annual growth prospect. Considering the great biodiversity existing in the country, the production of cosmetics from naturally occurring substances with such activities will be of great importance for the Brazilian industrial sector

From waste to energy: microalgae production in wastewater and glycerol.

The present work aimed to evaluate the auto/mixotrophic growth of microalgae using domestic wastewater (WW) amended with glycerol aiming biofuels production. The best results were obtained with the highest glycerol supplementation (50 mM). In such condition, Chlorella vulgaris and Botryococcus terribilis showed a biomass productivity of 118 and 282 mg l−1 d−1, which produced about 18 and 35 mg l−1 d−1 of lipids, respectively. Thus, if scaled-up (200 m3 d−1 of WW, 240 working days y−1) biomass and lipid yields may be about 5.6 tons y−1 and 894.2 kg y−1 or 13.5 tons y−1 and 1.6 tons y−1 for C. vulgaris and B. terribilis, respectively. The mixotrophic production of lipids can generate high quality biodiesel according to estimations using their fatty acids profiles. The whole process can be advantageously combined with the production of other biofuels (e.g. methane and bio-ethanol) in a biorefinery scenario. This combination of algal biomass production with waste treatment (WW amended with glycerol) can have a significant impact in the water treatment sector and local markets

Comparing the use of different domestic wastewaters for coupling microalgal production and nutrient removal.

The streams from municipal wastewater treatment plants (WWTP) have been considered a valuable medium for mass cultivation of algal biomass. The aim of this work is to test and compare the performance of Chlorella vulgaris on several streams from five stages, from two different WWTP. The results showed biomass yields ranging from 39 to 195 mg dry-weight l−1 days−1. The best performance as biomass production was obtained with the centrate (effluent from drying the anaerobic sludge). After testing a wide range of N/P ratios with centrate, the highest productivity and growth rates were obtained with the original N/P ratio (2.0) of this stream. The highest removal rates were of 9.8 (N) and 3.0 (P) mg l−1 days−1, in the centrate. Finally, this research also suggests that microalgal production seems to be a promising process when coupled to wastewater treatment

LuxCDABE—Transformed Constitutively Bioluminescent Escherichia coli for Toxicity Screening: Comparison with Naturally Luminous Vibrio fischeri

We show that in vitro toxicity assay based on inhibition of the bioluminescence of recombinant Escherichia coli encoding thermostable luciferase from Photorhabdus luminescens is a versatile alternative to Vibrio fischeri Microtox™ test. Performance of two luxCDABE-transformed E. coli MC1061 constructs (pDNlux) and (pSLlux) otherwise identical, but having 100-fold different background luminescence was compared with the performance of V. fischeri. The microplate luminometer and a kinetic Flash-Assay test format was used that differently from Microtox test is also applicable for high throughput analysis. Toxic effects (30-s till 30-min EC50) of four heavy metals (Zn, Cd, Hg, Cu) and three organic chemicals (aniline, 3,5-dichloroaniline and 3,5-dichlorophenol) were studied. Both E. coli strains had comparable sensitivity and the respective 30-min EC50 values highly correlated (log-log R2 = 0.99; p < 0.01) showing that the sensitivity of the recombinant bacteria towards chemicals analyzed did not depend on the bioluminescence level of the recombinant cells. The most toxic chemical for all used bacterial strains (E. coli, V. fischeri) was mercury whereas the lowest EC50 values for Hg (0.04–0.05 mg/L) and highest EC50 values for aniline (1,300–1,700 mg/L) were observed for E. coli strains. Despite of that, toxicity results obtained with both E. coli strains (pSLlux and pDNlux) significantly correlated with V. fischeri results (log-log R2 = 0.70/0.75; p < 0.05/0.01). The use of amino acids (0.25%) and glucose (0.05%)-supplemented M9 medium instead of leucine-supplemented saline significantly (p < 0.05) reduced the apparent toxicity of heavy metals to both E. coli strains up to three orders of magnitude, but had little or no complexing effect on organic compounds. Thus, P. luminescens luxCDABE-transformed E. coli strains can be successfully used for the acute toxicity screening of various types of organic chemicals and heavy metals and can replace V. fischeri in certain cases where the thermostability of luciferase >30 °C is crucial. The kinetic Flash Assay test format of the bioluminescence inhibition assay facilitates high throughput analysis. The assay medium, especially in case of testing heavy metals should be a compromise: optimal for the viability/luminescence of the recombinant test strain and of minimum complexing potential

Whole-Cell Fluorescent Biosensors for Bioavailability and Biodegradation of Polychlorinated Biphenyls

Whole-cell microbial biosensors are one of the newest molecular tools used in environmental monitoring. Such biosensors are constructed through fusing a reporter gene such as lux, gfp or lacZ, to a responsive promoter. There have been many reports of the applications of biosensors, particularly their use in assaying pollutant toxicity and bioavailability. This paper reviews the basic concepts behind the construction of whole-cell microbial biosensors for pollutant monitoring, and describes the applications of two such biosensors for detecting the bioavailability and biodegradation of Polychlorinated Biphenyls (PCBs)

Microbial diversity in waters, sediments and microbial mats evaluated using fatty acid-based methods

The review summarises recent advances towards a greater comprehensive assessment of microbial diversity in aquatic environments using the fatty acid methyl esters and phospholipid fatty acids approaches. These methods are commonly used in microbial ecology because they do not require the culturing of micro-organisms, are quantitative and reproducible and provide valuable information regarding the structure of entire microbial communities. Because some fatty acids are associated with taxonomic and functional groups of micro-organisms, they allow particular groups of micro-organisms to be distinguished. The integration of fatty acid-based methods with stable isotopes, RNA and DNA analyses enhances our knowledge of the role of micro-organisms in global nutrient cycles, functional activity and phylogenetic lineages within microbial communities. Additionally, the analysis of fatty acid profiles enables the shifts in the microbial diversity in pristine and contaminated environments to be monitored. The main objective of this review is to present the use of lipid-based approaches for the characterisation of microbial communities in water columns, sediments and biomats