scholarly journals Anaerobic Co-Digestion Effluent as Substrate for Chlorella vulgaris and Scenedesmus obliquus Cultivation

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4880
Author(s):  
Paolina Scarponi ◽  
Alessandro Bonetto ◽  
David Bolzonella ◽  
Sergi Astals ◽  
Cristina Cavinato

Anaerobic digestate supernatant can be used as a nutrient source for microalgae cultivation, thus integrating phytoremediation processes with high value products storage in microalgae biomass. Microalgae are able to use nitrogen and phosphorous from digestate, but high nutrient concentration can cause growth inhibition. In this study, two microalgae strains (C. vulgaris and S. obliquus) were cultivated on the anaerobic co-digestion supernatant (obtained from the organic fraction of municipal solid waste (OFMSW) and waste activated sludge (WAS)) in a preliminary Petri plate screening at different dilutions (1:10 and 1:5) using a synthetic medium (ISO) and tap water (TW). Direct Nile red screening was applied on colonies to preliminarily identify hydrophobic compound storage and then a batch test was performed (without air insufflation). Results show that C. vulgaris was able to grow on digestate supernatant 1:5 diluted, while Nile red screening allowed the preliminary detection of hydrophobic compound storage in colonies. The analysis carried out at the end of the test on ammonia, phosphate, nitrate and sulphate showed a removal percentage of 47.5 ± 0.8%, 65.0 ± 6.0%, 95.0 ± 3.0% and 99.5 ± 0.1%, respectively.

1997 ◽  
Vol 35 (11-12) ◽  
pp. 107-112 ◽  
Author(s):  
A. M. Shaban ◽  
G. E. El-Taweel ◽  
G. H. Ali

In the present study, the effect of UV radiation on the inactivation of a range of microorganisms was studied. Each organism was seeded into sterile tap water and exposed to UV in batch experiments with changing turbidities. In addition, the effect of UV on microbial communities in river Nile water was examined. It was found that 1min contact time (0.5L/min flow rate) was effective against vegetative cells levels almost reaching zero (except with Staphylococcus aureus). On the other hand, spore-forming bacteria, Candida albicans and coliphage were more resistant to UV. This contact time caused coenobia cells in single form with Scenedesmus obliquus while for Microcystis aeruginosa colonies broke into smaller groups. Exposure of Nile water microbial communities to UV showed that yeasts and Aeromonas survived better than the other organisms while in the phytoplankton partial fragmentation occurred in some algal groups. The protective effect of turbidity differed between organisms, with increased contact time under conditions of stable turbidity having no effect on the organisms. At 20 NTU the UV radiation had no effect on the morphological characters of algal cells. In reactivation experiments, it is clear that photoreactivation, and not dark repair, takes place with bacterial cells. Only coliphage had no photoreactivation and dark repair responses although with coliphage and host, both reactivation processes worked well. Moreover, the irradiated algae regained their normal shape after 3 days in suitable media and enough light.


1999 ◽  
Vol 65 (2) ◽  
pp. 822-827 ◽  
Author(s):  
Brian W. James ◽  
W. Stuart Mauchline ◽  
P. Julian Dennis ◽  
C. William Keevil ◽  
Robin Wait

ABSTRACT Chloroform-soluble material was extracted from two strains ofL. pneumophila serogroup 1 following growth in continuous culture. The purified material was identified as poly-3-hydroxybutyrate (PHB) by nuclear magnetic resonance spectroscopy and by gas chromatography-mass spectrometry. PHB yields of up to 16% of cell dry weight were extracted from culture samples. The PHB was located in electron-dense intracellular inclusions, which fluoresced bright yellow when stained with the lipophilic dye Nile red. A Nile red spectrofluorometric assay provided a more accurate and reliable determination of the PHB content. PHB accumulation increased threefold during iron-limited culture and was inversely related to the concentration of iron metabolized. Chemostat-grown cells survived in a culturable state for at least 600 days when incubated at 24°C in a low-nutrient tap water environment. Nile red spectrofluorometry and flow cytometry demonstrated that PHB reserves were utilized during starvation. PHB utilization, as revealed by the decline in mean cellular fluorescence and cell complexity, correlated with loss of culturability. Fluorescence microscopy provided visual evidence of PHB utilization, with a marked reduction in the number of Nile red-stained granules during starvation. Heat shock treatment failed to resuscitate nonculturable cells. This study demonstrates that L. pneumophila accumulates significant intracellular reserves of PHB, which promote its long-term survival under conditions of starvation.


2018 ◽  
Vol 197 ◽  
pp. 13010 ◽  
Author(s):  
I Gede Aditya Juliarnita ◽  
Rositayanti Hadisoebroto ◽  
Astri Rinanti

This preliminary study aims to exploit the biomass of microalgae Chlorella vulgaris; Scenedesmus obliquus; and Chlorococcum sp. in the form of a mixed culture as raw material of alternative fuels. Microalgae were cultivated in the artificial growth medium of PHM (Provasoli Haematococcus Media) for 9 days to reach the exponential phase. Hydrolysis was carried out at a temperature variation of (oC) 25; 80; 100; 120; 140; 160 within 30 minutes by adding hydrochloric acid. Biomass fermentation by adding 50% (v/v) Saccharomyces cerevisiae for 5 day to produce alcohol compounds. The last stage is separation of the alcohol compounds from another compounds by distillation. The result showed that carbohydrate levels with color change indicator in luff schoorl solution at hydrolysis and fermentation stages severely were 12.20 mg/L. Carbohydrate levels in fermentation stage produced 17% (v/v) alcohol compounds while in the distillation stage, 98% (v/v) alcohol will be separated into intermediate compounds such as linoleic acid and methyl alcohol as a characteristic of bioethanol. At 80oC of hydrolysis temperature, 58% bioethanol was produced. Further research is needed, since the preliminary study proves the mixed culture of microalgae is potentially to be utilized in producing bioethanol.


Author(s):  
Andreia Silva ◽  
Ricardo N. Coimbra ◽  
Carla Escapa ◽  
Sónia A. Figueiredo ◽  
Olga M. Freitas ◽  
...  

In view of the valorisation of the green microalga Scenedesmus obliquus biomass, it was used for the biosorption of two nonsteroidal anti-inflammatory drugs, namely salicylic acid and ibuprofen, from water. Microalgae biomass was characterized, namely by the determination of the point of zero charge (pHPZC), by Fourier transform infrared (FT-IR) analysis, simultaneous thermal analysis (STA) and scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS). Kinetic and equilibrium batch experiments were carried out and results were found to fit the pseudo-second order equation and the Langmuir isotherm model, respectively. The Langmuir maximum capacity determined for salicylic acid (63 mg g−1) was larger than for ibuprofen (12 mg g−1), which was also verified for a commercial activated carbon used as reference (with capacities of 250 and 147 mg g−1, respectively). For both pharmaceuticals, the determination of thermodynamic parameters allowed us to infer that adsorption onto microalgae biomass was spontaneous, favourable and exothermic. Furthermore, based on the biomass characterization after adsorption and energy associated with the process, it was deduced that the removal of salicylic acid and ibuprofen by Scenedesmus obliquus biomass occurred by physical interaction.


Author(s):  
S. Canizales ◽  
M. Sliwszcinka ◽  
A. Russo ◽  
S. Bentvelzen ◽  
H. Temmink ◽  
...  

AbstractSeveral technologies have aimed to recover nitrogen directly from urine. Nitrogen recovery in these technologies was limited by the mismatch of the nitrogen-phosphorus molar ratio (N:P) of urine, being 30–46:1, and that of the final product, e.g., 1:1 in struvite and 16–22:1 in microalgae biomass. Additionally, the high nitrogen concentrations found in urine can be inhibitive for growth of microorganisms. Cyanobacteria were expected to overcome phosphorus (P) limitation in urine given their ability to store an N-rich polymer called cyanophycin. In this study, it was found that the model cyanobacterium Synechocystis sp. PCC6803 did not experience significant growth inhibition when cultivated in synthetic medium with concentrations of 0.5 g ammonium-N L−1. In the case of urea, no inhibition was observed when having it as sole nitrogen source, but it resulted in chlorosis of the cultures when the process reached stationary phase. Synechocystis was successfully cultivated in a medium with 0.5 g ammonium-N L−1 and a N:P ratio of 276:1, showing the N:P flexibility of this biomass, reaching biomass N:P ratios up to 92:1. Phosphorus starvation resulted in cyanophycin accumulation up to 4%. Dilution of the culture in fresh medium with the addition of 118 mg N L−1 and 1.5 mg P L−1 (N:P of 174:1) resulted in a rapid and transient cyanophycin accumulation up to 11%, after which cyanophycin levels rapidly decreased to 3%.


2021 ◽  
Vol 9 ◽  
Author(s):  
Eli S. J. Thoré ◽  
Floris Schoeters ◽  
Audrey De Cuyper ◽  
Rut Vleugels ◽  
Isabelle Noyens ◽  
...  

To meet the increasing demands of the growing population and to cope with the challenges of global change, both the production of biological feedstock and the recovery of recyclable natural resources play a critical role. Microalgal biomass is a promising source of renewable multifunctional feedstock, but the production is costly and requires large amounts of water. Here, we explored the potential of using wastewater as culture medium to lower the economic and environmental costs of microalgae biomass production and evaluated its valorization opportunities for animal feed production. As a proof of principle, we show that Chlorella sorokiniana can be cultivated on poultry wastewater, with a 83 and 113% increase in productivity when wastewater was first 50% diluted with tap water or standard growth medium, respectively. Wastewater sterilization before use enhanced algal growth with 36–118%, but only when wastewater was 25–50% diluted with standard medium. In contrast, it offered no additional benefits when dilutions were made with tap water or when wastewater was not diluted. At the end of the 22-days experiment, a maximum biomass of 0.8–1.9 g L−1 was reached for algae grown on wastewater. The produced biomass had a high macronutrient content, and the heavy metal content was below maximum limits for use in animal feed. Likewise, the tested pathogen groups were reduced until below safety norms for feed production after algal growth in unsterilized 50% wastewater (diluted with tap water). Overall, these findings add to our growing knowledge on the cultivation of microalgae on wastewater and its valorization opportunities, paving the way for a more sustainable use and reuse of resources.


2006 ◽  
Vol 6 (6) ◽  
pp. 99-109 ◽  
Author(s):  
Q.L. Zhao ◽  
J.N. Zhang ◽  
S.J. You ◽  
S.H. Wang ◽  
L.N. Wang

Irrigation with tertiary effluent, secondary effluent, and raw wastewater (sewage) were studied with tap water irrigation as the control. The effects of the irrigations on the qualities of three testing crops: cucumber, celery cabbage and maize were investigated. The contents of residual chloride ion, phosphate, nitrate, nitrite, and residual heavy metals in these irrigated crops were also examined. The results showed that the secondary and tertiary effluent had no significant effects on the crop qualities. However, irrigation with the sewage could lead to increase parts of nutrient components in the crops. Irrigation with the sewage caused accumulation of nitrate and heavy metals in the crops, indicating that sewage was not suitable for irrigation. The risk assessment results suggested that the health risk of the irrigations using sewage and secondary effluent exceeded the maximum acceptable risk level. Comparatively, the risk in the tertiary effluent irrigation was much lower than the acceptable level.


Author(s):  
E. Keyhani

The matrix of biological membranes consists of a lipid bilayer into which proteins or protein aggregates are intercalated. Freeze-fracture techni- ques permit these proteins, perhaps in association with lipids, to be visualized in the hydrophobic regions of the membrane. Thus, numerous intramembrane particles (IMP) have been found on the fracture faces of membranes from a wide variety of cells (1-3). A recognized property of IMP is their tendency to form aggregates in response to changes in experi- mental conditions (4,5), perhaps as a result of translational diffusion through the viscous plane of the membrane. The purpose of this communica- tion is to describe the distribution and size of IMP in the plasma membrane of yeast (Candida utilis).Yeast cells (ATCC 8205) were grown in synthetic medium (6), and then harvested after 16 hours of culture, and washed twice in distilled water. Cell pellets were suspended in growth medium supplemented with 30% glycerol and incubated for 30 minutes at 0°C, centrifuged, and prepared for freeze-fracture, as described earlier (2,3).


Author(s):  
Anne M. Klinkner ◽  
Crystal R. Waites ◽  
Peter J. Bugelski ◽  
William D. Kerns

A primary effort in the understanding of the progression of atherosclerotic disease has been methods development for visualization of the atherosclerotic plaque. We introduce a new method for the qualitative analysis of lipids in atherosclerotic fatty streaks which also retains those lipids for biochemical evaluation. An original aspect of the process is the ability to view an entire fatty streak en face, selectively stained for specific lipid classes within the lesion.New Zealand white rabbits were fed a high cholesterol diet(0.15%-0.3% for 14 wks). The aorta was removed and fixed in Carson's phosphate buffered formaldehyde followed by dual staining in the fluorescent dyes Nile red and filipin. Stock solutions of nile red(0.5mg/ml acetone) and filipin(2.5mg/ml dimethyl formamide) were prepared and kept at -20°C; all subsequent steps were at RT. 0.5cm × 1.0cm pieces of aorta were trimmed and adventitia removed. The pieces were then washed 3×15 min in PBS w/o CaMg, soaked in Nile red(NR)/filipin(Fl) stain(100(il NR stock + 200μl Fl stock in 10 ml PBS for 30 min, washed in PBS 3×30 min, rinsed with distilled water, mounted(Crystal Mount, Biomedia) and coverslipped and viewed by fluorescence microscopy.


1955 ◽  
Vol 29 (5) ◽  
pp. 889-897 ◽  
Author(s):  
Francis M. Spencer ◽  
Lee S. Monroe

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