Bioprospecting of Indigenous Microalgae to Evaluate Their Potential for Bioenergy and Wastewater Treatment (original) (raw)
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Journal of Applied Phycology, 2016
The utilization of microalgae for wastewater treatment represents an attractive opportunity for wastewater valorization through the use of the produced biomass. Five strains of microalgae were isolated from municipal wastewater and grown in autoclaved and non-autoclaved effluent at 30°C and 150 μmol photons m −2 s −1 to study biomass production, nutrient removal, and the biochemical composition of the biomass. All strains reached high biomass productivity (35.6 to 54.2 mg dry weight L −1 day −1) within 4 days of batch culturing. In this period, ammonium-N and phosphate were reduced by more than 60 and 90 %, respectively. The high growth rate (0.57 to 1.06 day −1) ensured a rapid removal of nutrients and thereby a short retention time. By the fourth day of cultivation, the algal biomass contained 32 % protein, but only 11 % lipids and 18 % carbohydrates. It was found that the biomass was a suitable raw material for biogas production by anaerobic digestion. Biodigestion of obtained biomass was simulated by employing the Aspen HYSYS modeling software, resulting in methane yields comparable to those found in the literature. The elemental analysis of the algal biomass showed very low concentrations of pollutants, demonstrating the potential of use of the digestate from biodigestion as a bio-fertilizer.
Algal Research-Biomass Biofuels and Bioproducts, 2015
Microalgae are considered as one of the most promising sources of biomass for energy production. However, bioenergy production by microalgal culture is still not economically viable and it has high environmental impact (requirement of high amount of freshwater). These drawbacks can be surpassed by coupling microalgal biomass production with phycoremediation of wastewater. In this context, this study evaluates the kinetics of biomass production and nutrient removal by two microalgal species (Chlorella vulgaris and Pseudokirchneriella subcapitata) cultivated in different medium compositions. The potential of microalgae for biomass production and their high efficiency on nutrients removal from medium, particularly nitrogen and phosphorus, was demonstrated. Maximum biomass productivity was observed for C. vulgaris (0.106±0.004 g L-1 d-1), while P. subcapitata reached a maximum of 0.050±0.001 g L-1 d-1. The value of N:P molar ratio that favoured microalgal growth was 8:1 for C. vulgaris and 16:1 for P. subcapitata. A complete removal (100%) of ammonium was measured and high removal efficiencies were observed for nitrate (above 95%) and phosphate (above 97%). Microalgae were also able to efficiently remove sulphates, presenting removal efficiencies from 54 to 100%. The removal kinetics for all the nutrients have been determined through application of pseudo-first-order kinetic model and modified Gompertz model. In conclusion, this work gives relevant data for culturing microalgae in wastewater, contributing to the bioprocess design of a sustainable and low-cost production of microalgal biomass.
International Journal of Environmental Science and Technology, 2014
Discharge of untreated domestic and industrial wastewater into aquatic bodies is posing a serious eutrophication threat, leading to a slow degradation of the water resources. A number of physical, chemical and biological methods have been developed for the treatment of wastewaters; among these, the use of microalgae is considered as a more eco-friendly and economical approaches. Microalgae are versatile organisms which perform multiple roles in the environment-bioremediation of wastewater, gleaning of excess nutrients and in turn, generate valuable biomass which finds applications in the food, biofuel and pharmaceutical industries. They are currently being utilized to reduce the high nutrient load (especially N and P) from wastewaters, which fulfill the growth requirements of microalgae, making it a suitable cultivation medium for biomass production. The present review represents a comprehensive compilation of reports on microalgal diversity of wastewaters, followed by a critical overview of their utilization, suitability and potential in bioremediation visa -vis biomass production. This review also emphasizes the superiority of polyalgal and consortial approaches in wastewater treatment, as compared to the use of unialgal inocula, besides providing useful pointers for future research needs in this area.
2017
Increasing population and Industrialization are key pollutant contributors in water bodies. These wastes are highly hazardous for humansand ecosystem and require a comprehensive, effective treatment before discharge into water bodies. Over the years, many up gradations have been introduced in traditional water treatment methods which were expensive and ineffective especially for removal of heavy metals. Micro alga has been gaining attention due to its mutual benefit in wastewater treatment and for valuable algae biomass production. Waste water especially sewage and industrial effluents are rich in pathogenic organisms, organic, inorganic and heavy metals that adversely affect human and aquatic life. Algae use these inorganic and heavy metals for its growth. In addition it also reduces pathogenic organism and release oxygen to be used by bacteria for decomposition of organic compounds in secondary treatment. In this review, we will discuss potential of microalgae in wastewater treatm...
Applied Energy, 2011
Global threats of fuel shortages in the near future and climate change due to green-house gas emissions are posing serious challenges and hence and it is imperative to explore means for sustainable ways of averting the consequences. The dual application of microalgae for phycoremediation and biomass production for sustainable biofuels production is a feasible option. The use of high rate algal ponds (HRAPs) for nutrient removal has been in existence for some decades though the technology has not been fully harnessed for wastewater treatment. Therefore this paper discusses current knowledge regarding wastewater treatment using HRAPs and microalgal biomass production techniques using wastewater streams. The biomass harvesting methods and lipid extraction protocols are discussed in detail. Finally the paper discusses biodiesel production via transesterification of the lipids and other biofuels such as biomethane and bioethanol which are described using the biorefinery approach.
Evaluation of microalgae production coupled with wastewater treatment
Environmental technology, 2017
In the present study the feasibility of microalgae production coupled with wastewater treatment was assessed. Continuous cultivation of Chlorella sorokiniana with wastewater was tested in lab-scale flat panel photobioreactors. Biomass productivity was determined for four dilution rates (4.32 d(-1), 3.6 d(-1), 1.8 d(-1) and 0.72 d(-1)). The productivity peak was 1.524 g l(-1)d(-1) at the dilution rate of 2.41 d(-1). Nitrogen and phosphorus removals were found to be inversely proportional to dilution rates, while COD removal was found to be 50% at all the tested conditions. The biomass obtained at the highest dilution rate was characterized for its content of lipids, proteins and pigments. The average yields of fatty acid methyl esters (FAME), protein, lutein, chlorophylls and β-carotene was 62.4 mg, 388.2 mg, 1.03 mg, 11.82 mg and 0.44 mg per gram dry biomass, respectively. Economic analysis revealed that potentially more than 70% of revenue was from the production of pigments, i.e. ...
Wastewater as a Source of Nutrients for Microalgae Biomass Production
Biofuel and Biorefinery Technologies, 2015
Production of microalgal biomass requires large amounts of nitrogen (N) and phosphorus (P). The sustainability and economic viability of microalgae production could be significantly improved if N and P are not supplied by synthetic fertilizers but with wastewater. Microalgae already play an important role in wastewater treatment, yet several challenges remain to optimally convert wastewater nutrients into microalgal biomass. This book chapter aims to give an overview of the potential of using wastewater for microalgae production, as well some challenges that should be taken into account. We also review the benefits of combining microalgal biomass production with wastewater treatment.
Selection of microalgae for wastewater treatment and potential lipids production
Bioresource Technology, 2013
Effective synthetic wastewater treatment by saline and freshwater microalgae. Marine species exhibited higher growth rates than the freshwater species. Scenedesmus rubescens and Neochloris vigensis gave higher lipids concentration. The highest algal lipid content was observed after 20 days of operation.
Microalgae Cultivation for Wastewater Treatment and Bioenergy Generation
CRC Press eBooks, 2023
The process of cultivation of microalgae on purified and clarified wastewater of Kuryanovo wastewater treatment plants (KWWTP) was studied. The studies were conducted on monoculture (Scenedesmus quadricauda and Chlorella sorokiniana) and on polyculture, the composition of which was formed from microalgae present in the wastewater. The authors created and investigated the columnar photobioreactor (PBR), which acted as a pilot project on the purified and clarified water of KWWTP and allowed the removal of total nitrogen and phosphorus phosphates with an efficiency of up to 90%. The formation of a stable biocenosis from 22 species of algae (with 3-4 dominant species) and 31 species of zooplankton organisms belonging to six systematic subdivisions was recorded. The optimal retention time of the microalgae polyculture for the most effective wastewater treatment has been determined. The conducted studies have shown that the depth of decomposition of ashless matter and the ultimate biogas potential of untreated microalgae biomass is 15% lower than the corresponding values obtained with digestion of activated sludge, which necessitates studies in the field of pretreatment of algal biomass. The paper shows: connections between chlorophyll-a content, algal biomass and fluorescence index F 0 and between biomass increment and Fv/Fm value.
World journal of microbiology & biotechnology, 2016
Untreated wastewaters have been a great concern and can cause major pollution problems for environment. Conventional approaches for treating wastewater involve tremendous capital cost, have major short comings and are not sustainable. Microalgae culture offers an interesting step for wastewater treatment. Microalgae serve the dual purpose of phycoremediation along with the production of potentially valuable biomass, which can be used for several purposes. The ability of microalgae to accumulate nitrogen, phosphorus, heavy metals and other toxic compounds can be integrated with wastewater treatment system to offer an elegant solution towards tertiary and quaternary treatment. The current review explores possible role of microalgal based wastewater treatment and explores the current progress, key challenges, limitations and future prospects with special emphasis on strategies involved in harvesting, boosting biomass and lipid yield.