Effect of lake water on algal biomass and microbial community structure in municipal wastewater-based lab-scale photobioreactors
- 849 Downloads
Photobioreactors are a novel environmental technology that can produce biofuels with the simultaneous removal of nutrients and pollutants from wastewaters. The aim of this study was to evaluate the effect of lake water inoculation on the production of algal biomass and phylogenetic and functional structure of the algal and bacterial communities in municipal wastewater-treating lab-scale photobioreactors. Inoculating the reactors with lake water had a significant benefit to the overall algal biomass growth and nutrient reduction in the reactors with wastewater and lake water (ratio 70/30 v/v). The metagenome-based survey showed that the most abundant algal phylum in these reactors was Chlorophyta with Scenedesmus being the most prominent genus. The most abundant bacterial phyla were Proteobacteria and Bacteroidetes with most dominant families being Sphingobacteriaceae, Cytophagaceae, Flavobacteriaceae, Comamonadaceae, Planctomycetaceae, Nocardiaceae and Nostocaceae. These photobioreactors were also effective in reducing the overall amount of pathogens in wastewater compared to reactors with wastewater/tap water mixture. Functional analysis of the photobioreactor metagenomes revealed an increase in relative abundance genes related to photosynthesis, synthesis of vitamins important for auxotrophic algae and decrease in virulence and nitrogen metabolism subsystems in lake water reactors. The results of the study indicate that adding lake water to the wastewater-based photobioreactor leads to an altered bacterial community phylogenetic and functional structure that could be linked to higher algal biomass production, as well as to enhanced nutrient and pathogen reduction in these reactors.
KeywordsBiomass production Metagenome analysis Photobioreactor Wastewater treatment
The authors received financial support for this research from the Knowledge Foundation (2011006), VINNOVA (2012-01243), SVU (12-123), Läckeby Water and Mälarenergi, and the Ministry of Education and Research of the Republic of Estonia (grants IUT2-16 and 3.2.0801.11-0026). The authors would also like to thank Kristjan Oopkaup and Mae Uri from the Institute of Ecology and Earth Sciences at the University of Tartu and Viktor Sjöberg from Örebro University for their advice.
Compliance with ethical standards
Authors have no conflicts of interest in regards to the research presented in this paper. No human participants and/or multi-cellular animals were used in the conducted experiments.
- Awuah E (2007) Pathogen removal mechanisms in macrophyte and algal waste stabilization ponds: PhD: UNESCO-IHE Institute, Delft - CRC Press Book. Retrieved February 04, 2015, from http://www.crcpress.com/product/isbn/9780415416955
- Bellinger EG, Sigee DC (2010) Freshwater algae identification and use as bioindicators. John Wiley & Sons, Ltd, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, UKGoogle Scholar
- Fields MW, Hise A, Lohman EJ, Bell T, Gardner RD, Corredor L, Moll K, Peyton BM, Characklis GW, Gerlach R (2014) Sources and resources: importance of nutrients, resource allocation, and ecology in microalgal cultivation for lipid accumulation. Appl MicrobiolBiot 98:4805–4816Google Scholar
- Krohn-Molt I, Wemheuer B, Alawi M, Poehlein A, Güllert S, Schmeisser C, Pommerening-Röser A, Grundhoff A, Daniel R, Hanelt D, Streit WR (2013) Metagenome survey of a multispecies and alga-associated biofilm revealed key elements of bacterial-algal interactions in photobioreactors. Appl Environ Microb 79(20):6196–6206CrossRefGoogle Scholar
- Overbeek R, Begley T, Butler RM, Choudhuri JV, Chuang H-Y, Cohoon M, de Crécy-Lagard V, Diaz N, Disz T, Edwards R, Fonstein M, Frank ED, Gerdes S, Glass EM, Goesmann A, Hanson A, Iwata-Reuyl D, Jensen R, Jamshidi N, Krause L, Kubal M, Larsen N, Linke B, McHardy AC, Meyer F, Neuweger H, Olsen G, Olson R, Osterman A, Portnoy V, Pusch GD, Rodionov DA, Rückert C, Steiner J, Stevens R, Thiele I, Vassieva O, Ye Y, Zagnitko O, Vonstein V (2005) The subsystems approach to genome annotation and its use in the project to annotate 1000 genomes. Nucleic Acids Res 33(17):5691–5702PubMedCentralPubMedCrossRefGoogle Scholar