The aim of this work was to study the ability of two different strains of the yeast Yarrowia lipolytica
to grow on Olive Mill Wastewater (OMW) and their potential to produce high-value products such as
lipases. Factors affecting cellular growth and OMW degradation were studied, such as nitrogen
supplementation, cells concentration and surfactant addition. Both strains used were able to grow in a
OMW with a COD of 19 g/L and total phenols concentration of around 800 mg/L. The strain W29
presented the highest potential for extracellular lipase production from OMW. Lipase productivity
was improved by the medium supplementation with ammonium sulphate up to 6 g/L, leading to 80 %
of COD degradation and 70 % of total phenols reduction. The surfactant Tween 80 enhanced cell
growth and COD degradation, but had no significant effect on lipase productivity. The results
evidenced that the conditions that favoured lipase production differ from the conditions that improve
COD removal from OMW.
This work aimed to apply a sequential batch operation mode to promote the biomethanation of a
real dairy wastewater enriched in fat. Three cycles were conducted with biomass previously acclimated to
oleic acid. Soluble COD, VFA and methane content were analyzed in each cycle at different time intervals.
The soluble COD removal efficiency improved slightly in each new feed and the total VFA levels detected
decreased successively. The maximum cumulative methane production also improved from cycle 1 to cycle
3. These results contribute to support the idea that the key for the degradation of effluents with high lipid
content is to sequence adsorption and degradation steps during the treatment process.
In the present study, we investigate the biodegradability of oleic acid by sludge from anaerobic filter reactor fed with olive mill wastewater (sludge T). A comparative study was conducted using a second sludge from an expanded granular bed reactor exposed to oleic acid (sludge P). The performance of treating oleic acid and the influence of the composition of the culture media were investigated and compared. Methane production by sludge T started after a lag phase of 150 hours. However no lag phase was observed with sludge P. In contrast a higher methane production was obtained with the sludge T. The addition of nutrients (minerals and yeast extract) to culture medium reduced the lag phase of methane production by 40 hours.
In vineyards the presence of certain fungi may lead to the production of the mycotoxin ochratoxin A (OTA) and subsequent contamination of grapes and wine. Furthermore, winery wastewaters contaminated with OTA may represent an environmental hazard. Therefore it is imperative to assess the fate of this mycotoxin in conventional wastewater treatment systems.
The aim of the present work in this context is to assess the biological degradation of OTA. Experimental work was carried out in batch experiments with initial OTA to biomass concentration ratios (S0/X0) of 1.4 ?g mg-1, 7.4 ?g mg-1 and 11.9 ?g mg-1. The assays were inoculated with activated sludge biomass unadapted to the substance under examination. The proposed bioassay demonstrates that OTA concentrations up to 100 ?g L-1 can be degraded by microbial activity in activated sludge.
In vineyards the presence of certain fungi may lead to the production of the mycotoxin ochratoxin
A (OTA) and subsequent contamination of grapes and wine. Furthermore, winery wastewaters
contaminated with OTA may represent an environmental hazard. Therefore, it is imperative to assess the
fate of this mycotoxin in conventional wastewater treatment systems. The aim of the present work was to
assess the biological degradation of OTA. Experimental work was carried out in batch experiments with
initial OTA to biomass concentration ratios of 1.4 mgmg-1, 7.4mgmg-1 and, 11.9 mgmg-1. The assays
were inoculated with activated sludge biomass unadapted to the substance under examination. The
proposed bioassay demonstrates that OTA concentrations up to 100 mgL -1can be degraded by microbial
activity in activated sludge.; Fundação para a Ciência e a Tecnologia (FCT)
The ability of the strains Yarrowia lipolytica and Candida rugosa to grow on Olive Mill Wastewater (OMW) based medium and to produce high-value compounds from OMW (such as enzymes), while degrading this waste, was tested. Factors affecting cellular growth and OMW degradation were also studied, such as OMW composition, dilution and supplementation. OMW collected from 3-phase olive mill of the north region of Portugal were used and characterized chemical
and biochemically. OMW with COD ranging from 100 g·L-1 to 200 g·L-1 were supplemented with yeast extract and ammonium chloride proportionally to its organic composition. Preliminary studies of OMW consumption were carried out in batch cultures of Y. lipolytica W29 and C. rugosa PYCC 3238.
The strains were able to grow in the OMW used without dilution, to consume almost all of the sugars present in the media and to significantly reduce COD.
Y. lipolytica W29 was less affected by operating conditions changes such as, stirring rate variation and OMW medium supplementation.; Fundação para a Ciência e a Tecnologia (FCT) - PTDC/AMB/69379/2006, SFRH/BD/27915/2006.
BACKGROUND: The aim of this work was to study the ability of two different wild type strains of the yeast Yarrowia lipolytica to grow on olive mill wastewater (OMW) and their potential to produce high-value products such as lipases. Factors that affect cellular growth and OMW degradation were studied, such as nitrogen supplementation, cells concentration and surfactant addition.
RESULTS: Both strains, W29 and IMUFRJ 50682, were able to grow in OMW with 19 g L-1 of COD and approximately 800 mg L-1 of total phenols concentration. The strain W29 presented the highest potential for extracellular lipase production in OMW medium. Lipase productivity was improved by the medium supplementation with ammonium sulphate up to 6 g L-1, leading to 80% of COD degradation and 70% of total phenols reduction. The surfactant Tween 80 enhanced cell growth and COD degradation, but had a negative effect on lipase activity.
CONCLUSIONS Y. lipolytica has a great potential for OMW valorisation by its use as culture medium for biomass and enzymes production. The operating conditions that favoured lipase production differ from the conditions that improve COD reduction.; Fundação para a Ciência e a Tecnologia (FCT)
The ability of lipolytic yeasts to grow on olive mill wastewater (OMW)-based medium and to produce high-value compounds while degrading this waste, was tested. OMW collected from three-phase olive mills from the North region of Portugal were characterized and used. OMW with COD ranging from 100 g L?1 to 200 g L?1 were supplemented with yeast extract and ammonium chloride. Studies of OMW consumption were carried out in batch cultures of Candida rugosa, Candida cylindracea and Yarrowia lipolytica. All strains were able to grow in the OMW-based media, without dilution, to consume reducing sugars and to reduce COD. C. cylindracea was the best strain concerning the lipase production and the reduction of phenolic compounds and COD. For all strains, the phenols degradation was quite difficult, mostly when more easily degradable carbon source is still present in the medium. Among the phenolic compounds tested catechol is the most inhibitory to the cells.; Fundação para a Ciência e a Tecnologia (FCT) - Project PTDC/AMB/69379/2006; Grant SFRH/BD/27915/2006
Olive mill wastewater (OMW) is a liquid waste that results in large amounts from the olive oil manufacturing industry. The quality and quantity of OMW constituents are dependent of many factors, such as olives type and maturity, climatic conditions and region of origin, cultivation methods, and technology used for oil extraction1. From the 3-phases centrifugation process around 1.6 cubic meters of OMW per ton of olives processed are generated. These liquid wastes present an environmental problem and many solutions have been proposed for it, such as its use as culture medium for different lipolytic yeast strains (Gonçalves et al, 2009; Lopes et al, 2009). The aim of this work is the comparison of batch and fed-batch mode of operation for the lipase production and the OMW degradation by two strains, Yarrowia lipolytica W29 and Candida cylindracea CBS 7869. OMW collected from 3-phase continuous olive mills were used (COD of 30 to 261 g/L). OMW used without dilution was supplemented with ammonium chloride and yeast extract proportionally to the COD values. Batch and fed-batch cultures were conducted in a fermenter of 2 L of capacity at pH 7.2, 500 rpm, with constant or variable aeration rate for batch or fed-batch operation, respectively. Batch operation was more adequate to lipase production than fed-batch for both strains but the difference was more significant for Candida cylindracea that revealed to be the most efficient strain for lipase production. However...
Olive mill wastewater (OMW) characteristics make it a suitable resource to be used as a microbial culture media to produce value-added compounds, such as enzymes. In this work, the ability of the novel species Aspergillus ibericus to discolor OMW and produce lipase was studied. An initial screening on plates containing an OMW-based agar medium and an emulsified olive oil/rhodamine-B agar medium was employed to select the strain A. ibericus MUM 03.49. Then, experiments in conical flasks with liquid OMW-based media showed that the fungus could growth on undiluted OMW, with a chemical oxygen demand (COD) of 97 ± 2 g/L, and to produce up to 2,927 ± 54 U/L of lipase. When pure OMW was used in the media, the maximum COD and color reduction achieved were 45 and 97 %, respectively. When OMW diluted to 10 % was used, A. ibericus was able to reduce phenolic and aromatic compounds by 37 and 39 %, respectively. Additionally, lipase production was found to be promoted by the addition of mineral nutrients. When the fermentations were scaled up to a 2-L bioreactor, A. ibericus produced up to 8,319 ± 33 U/L of lipase, and the maximum COD and color reduction were 57 and 24 %, respectively.
The increased prevalence of antibiotic resistance is one of the main problems
faced by health professionals nowadays, consequently dealing with the expansion of
nosocomial infections in hospitals and other health institutions.
Wastewater Treatment Plants (WWTP) aim at the treatment of residual waters
ensuring the preservation of the environment and ultimately, human health.
Nevertheless, they also receive residual water from health institutions and research
centres that can significantly contribute to the presence of pathogenic and resistant
microorganisms in the sewage.
The aim of this study was the isolation of potential pathogenic bacteria (E.coli,
S.aureus, S.enterica, P.aeruginosa and K.pneumoniae) from the final effluent of four
WWTP in the north of Portugal to subsequently evaluate some known virulence
factors, such as their ability as biofilm formers and their susceptibility to different
The amount of E. coli surpassed all the other species and S.aureus was the less
frequent, considering all samples. The ability of biofilm formation depended on the
species considered, but also on the sampled WWTP. For instance, S.enteritidis and
E.coli showed low capacity to form biofilm, but they appeared with high CFU values.
S.aureus showed a high capacity of biofilm formation but only a small number of CFU
was counted. These data seem to indicate that S.aureus biofilms contain a huge
amount of polymeric matrix...
Anaerobic degradation of olive mill wastewater (OMW) at concentrations ranging from 2 to 100 g/L of chemical oxygen demand (COD) was assessed in batch assays. Methane was the main final product obtained for the lower concentrations tested. For 25 g COD/L, H2 was temporarily produced, albeit H2 depletion occurred, likely due to homoacetogenesis, since acetate was formed concomitantly. Hydrogen was produced and accumulated permanently in the assays containing 50 g COD/L of OMW. Methanogenesis and homoacetogenesis were naturally inhibited, suggesting that hydrogen recovery from OMW can be performed without the addition of methanogenic suppressors such as 2-bromoethanosulfonate. This fact opens new perspectives for the utilization of high OMW concentrations in a two-stage valorisation process combining biohydrogen and biomethane production.
This study is focused on the diversity of bacterial communities from two series of horizontal subsurface flow constructed wetlands (CW) polishing high salinity tannery wastewater. Each series was planted with Arundo donax or Sarcocornia sp. in a substrate composed by expanded clay and sand. Chemical and biochemical oxygen demand removal efficiencies were similar in each series, varying between 58 and 67% (inlet COD 218 ± 28 mg L?1) and 60 and 77% (inlet BOD5 37 ± 6 mg L?1), respectively. High numbers of culturable bacteria were obtained from substrate and root samples – 5.75 × 106-3.95 × 108 CFU g?1 recovered on marine agar and 1.72 × 107-8.46 × 108 CFU g?1 on nutrient agar. Fifty bacterial isolates were retrieved from the CW, related phylogenetically to Firmicutes, Actinobacteria, Bacteroidetes, ?-, ?-, and ?-Proteobacteria. Changes in the bacterial communities, from roots and substrate of each series, related to the plant species, hydraulic loading rates and along CW operation were examined using denaturating gradient gel electrophoresis (DGGE). The clustering analysis suggested that a diverse and distinct bacterial community inhabits each series, which was related to the type of plant present in each CW.
"A method based on sample preparation by solid phase extraction and analysis by liquid chromatography and mass spectrometry was validated and used for simultaneous analysis of cocaine, benzoylecgonine and cotinine in samples collected at the major wastewater treatment plant in the city of Lisbon. The aim was to estimate the consumption of both cocaine and nicotine in this community and establish an index involving both drugs supported by the relevance of nicotine as a significant anthropogenic marker. The study was made on two different weekdays during a month in order to evaluate patterns of consumption outside weekends. Cocaine and nicotine ingestion levels were back-calculated and expressed as mass of pure drugs consumed per day and per 1000 inhabitants (mean: 0.604 g and 5.860 g respectively). Cocaine was also expressed on the basis of local drug purity levels (33.7%) with a corresponding increase on dose assessments, and community drug abuse profiles. The authors sustain that this approach should always be included in drug studies of this kind allowing a better drug abuse assessment. No significant different patterns of consumption were obtained during the working days studied with the exception of one case coincident with a national holiday that showed an increased typical profile found on other non-working day studies...
This paper presents a parametric programming technique for the optimal design of industrial wastewater treatment networks (WTN) featuring multiple contaminants. Inspired in scientific notation and powers of ten, the proposed approach avoids the non-convex bilinear terms through a piecewise decomposition scheme that combines the generation of artificial flowrate variables with a multi-parameterization of the outlet concentration variables. The general non-linear problem (NLP) formulation is replaced by a mixed-integer linear programming (MILP) model that is able to generate near optimal solutions, fast. The performance of the new approach is compared to that of global optimization solver BARON through the solution a few test cases.
Cork boiling wastewater (CBW) is a very important effluent of the cork processing industry which is produced in the western Mediterranean region and western north of Africa. CBW has no utility till now constituting an environmental hazard. It is a complex liquid stream which is produced during the boiling of the cork planks. This process step is one of the key operations in cork processing. CBW is known as having suspended and dissolved solids and organic materials such as phenolic compounds being characterized by a low biodegradability and an acid pH.
This work aims to develop a procedure that explores the different types of valorization that can be obtained by integrating a biological process, such as the anaerobic digestion, to promote the bioconversion of the industrial cork effluents (cork boiling wastewater, CBW).
In addition to energy benefits, anaerobic digestion offers other interesting advantages. The cork industry is of great environmental, economic and social significance in the western Mediterranean region, with Portugal being the world-leading producer and exporter. Cork boiling wastewater (CBW) is a toxic and recalcitrant
organic effluent produced by this sector, which constitutes a serious environmental hazard. However, there is no documented research on anaerobic treatment/valorization
performed with this effluent. The work presented here was developed with the aim to use the anaerobic digestion process to convert the CBW polluting organic load into
an energy carrier gas and valuable molecules for industry.
Anaerobic digestion and the electrochemical oxidation were used to valorise the effluent of the olive oil production (olive mill wastewater, OMW). Anaerobiosis was realized
in an anerobic hybrid reactor, operating at a low hydraulic retention time of about 6 days and digesting the raw OMW, without any previous substrate altarations. Electrochemical process worked with a dimensionally stable anode (DSA), without adding further support electrolytes, at low potential values and at moderate dulution
factor of the substrate.
European Journal of Operational Research, nº 73 (1994); The problem of the optimization of regional wastewater systems may be generally
formulated as follows: to define the transport and treatment system, in a region or water basin, which assure compliance with given pollution control criteria, with minimum cost. In addition, one may try to satisfy other objectives, such as minimum environmental impact, better effluent reuse or adequate phasing. From the optimization point of view, the two main problems that render the solution difficult are the dimensionality and the concavity of cost functions. The matter has been dealt with by many authors, who have produced varied techniques to try to solve this problem. This
paper begins with a brief review of the work of those authors who have produced models
specifically designed to study the problem. Then, solution strategies are discussed concerning three major items: definition of the objective function and constraints, optimization method and practical
aplicability of the models. The paper concludes with the discussion of topics for future research.