Search

Periphyton-based bioreactors are widely accepted for removing various pollutants from wastewater; however, the slow start-up and low efficiency in widely fluctuating temperatures limit its application. A spiral periphyton bioreactor (SPR) was developed and its COD removal capability and the associated microbial communities were investigated. This SPR can be easily backwashed to stimulate periphyton growth and efficiently remove COD at temperatures ranging from 4 to 30 °C. The species richness and evenness of the periphyton community increased during domestication, while its functional diversity and organic carbon metabolic vitality were higher after 30 days domestication. Cyanobacteria were the main components of the SPR and produced an aerobic environment, while Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria and Sphingobacteria were the microorganisms responsible for COD removal. This study provides valuable insights into changes in pivotal microorganisms of the periphyton community during domestication, and indicates that SPR is simple to operate and efficient in COD removal., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Background and aims: Phosphate-solubilizing bacteria (PSB) possess significant potential for enhancing soil phosphorus bioavailability, but their efficacy may be constrained by carbon and nitrogen availability. Algae exhibit synergistic interactions with bacteria through producing active organic carbon. However, the influence of algae and PSB together on phosphorus bioavailability under varying nitrogen levels remains unclear.We conducted a microcosm experiment to explore the effects of applying Chlorella-Bacillus biofertilizer, along with various nitrate addition amounts, on both soil microbial community composition and phosphorus bioavailability. In addition, we employed a co-culture of Chlorella and Bacillus with different nitrogen concentrations to investigate the possible effects of nitrate addition on the production of organic anions and phosphatases of the Chlorella-Bacillus communities by using metabolomic analysis.Chlorella-Bacillus biofertilizer significantly increased soil Olsen-P concentration via strong interactive effects correlating with the various nitrate addition amounts in the microcosm experiment. These effects were due mainly to reducing the algal diversity, soil pH, and changing dissolved organic matter (DOM) characteristics, especially increasing the humification index (HIX). The metabolomic analyses of co-culture confirm that pathways related to the biosynthesis of fatty acids and phosphatases production are enhanced when nitrogen levels are high.Chlorella-Bacillus biofertilizer has significantly interactive effects with nitrate addition on soil phosphorus bioavailability by influencing soil DOM, pH and production of organic anions and phosphatases. These insights are useful for optimizing bio-fertilizer-nitrate combinations for increasing phosphorus bioavailability thereby reducing chemical fertilizer requirements.Methods: Phosphate-solubilizing bacteria (PSB) possess significant potential for enhancing soil phosphorus bioavailability, but their efficacy may be constrained by carbon and nitrogen availability. Algae exhibit synergistic interactions with bacteria through producing active organic carbon. However, the influence of algae and PSB together on phosphorus bioavailability under varying nitrogen levels remains unclear.We conducted a microcosm experiment to explore the effects of applying Chlorella-Bacillus biofertilizer, along with various nitrate addition amounts, on both soil microbial community composition and phosphorus bioavailability. In addition, we employed a co-culture of Chlorella and Bacillus with different nitrogen concentrations to investigate the possible effects of nitrate addition on the production of organic anions and phosphatases of the Chlorella-Bacillus communities by using metabolomic analysis.Chlorella-Bacillus biofertilizer significantly increased soil Olsen-P concentration via strong interactive effects correlating with the various nitrate addition amounts in the microcosm experiment. These effects were due mainly to reducing the algal diversity, soil pH, and changing dissolved organic matter (DOM) characteristics, especially increasing the humification index (HIX). The metabolomic analyses of co-culture confirm that pathways related to the biosynthesis of fatty acids and phosphatases production are enhanced when nitrogen levels are high.Chlorella-Bacillus biofertilizer has significantly interactive effects with nitrate addition on soil phosphorus bioavailability by influencing soil DOM, pH and production of organic anions and phosphatases. These insights are useful for optimizing bio-fertilizer-nitrate combinations for increasing phosphorus bioavailability thereby reducing chemical fertilizer requirements.Results: Phosphate-solubilizing bacteria (PSB) possess significant potential for enhancing soil phosphorus bioavailability, but their efficacy may be constrained by carbon and nitrogen availability. Algae exhibit synergistic interactions with bacteria through producing active organic carbon. However, the influence of algae and PSB together on phosphorus bioavailability under varying nitrogen levels remains unclear.We conducted a microcosm experiment to explore the effects of applying Chlorella-Bacillus biofertilizer, along with various nitrate addition amounts, on both soil microbial community composition and phosphorus bioavailability. In addition, we employed a co-culture of Chlorella and Bacillus with different nitrogen concentrations to investigate the possible effects of nitrate addition on the production of organic anions and phosphatases of the Chlorella-Bacillus communities by using metabolomic analysis.Chlorella-Bacillus biofertilizer significantly increased soil Olsen-P concentration via strong interactive effects correlating with the various nitrate addition amounts in the microcosm experiment. These effects were due mainly to reducing the algal diversity, soil pH, and changing dissolved organic matter (DOM) characteristics, especially increasing the humification index (HIX). The metabolomic analyses of co-culture confirm that pathways related to the biosynthesis of fatty acids and phosphatases production are enhanced when nitrogen levels are high.Chlorella-Bacillus biofertilizer has significantly interactive effects with nitrate addition on soil phosphorus bioavailability by influencing soil DOM, pH and production of organic anions and phosphatases. These insights are useful for optimizing bio-fertilizer-nitrate combinations for increasing phosphorus bioavailability thereby reducing chemical fertilizer requirements.Conclusion: Phosphate-solubilizing bacteria (PSB) possess significant potential for enhancing soil phosphorus bioavailability, but their efficacy may be constrained by carbon and nitrogen availability. Algae exhibit synergistic interactions with bacteria through producing active organic carbon. However, the influence of algae and PSB together on phosphorus bioavailability under varying nitrogen levels remains unclear.We conducted a microcosm experiment to explore the effects of applying Chlorella-Bacillus biofertilizer, along with various nitrate addition amounts, on both soil microbial community composition and phosphorus bioavailability. In addition, we employed a co-culture of Chlorella and Bacillus with different nitrogen concentrations to investigate the possible effects of nitrate addition on the production of organic anions and phosphatases of the Chlorella-Bacillus communities by using metabolomic analysis.Chlorella-Bacillus biofertilizer significantly increased soil Olsen-P concentration via strong interactive effects correlating with the various nitrate addition amounts in the microcosm experiment. These effects were due mainly to reducing the algal diversity, soil pH, and changing dissolved organic matter (DOM) characteristics, especially increasing the humification index (HIX). The metabolomic analyses of co-culture confirm that pathways related to the biosynthesis of fatty acids and phosphatases production are enhanced when nitrogen levels are high.Chlorella-Bacillus biofertilizer has significantly interactive effects with nitrate addition on soil phosphorus bioavailability by influencing soil DOM, pH and production of organic anions and phosphatases. These insights are useful for optimizing bio-fertilizer-nitrate combinations for increasing phosphorus bioavailability thereby reducing chemical fertilizer requirements. [ABSTRACT FROM AUTHOR]

Innovative and cost-effective technologies for advanced nutrient removal from surface water are urgently needed for improving water quality. Conventional biotechnologies, such as ecological floating beds, or constructed wetlands, are not effective in removing nutrients present at low-concentration. However, microalgae-bacteria consortium is promising for advanced nutrient removal from wastewater. Suspended algal-bacterial systems can easily wash out unless the hydraulic retention time is long, attached microalgae-bacteria consortium is more realistic. This critical review summarizes the fundamentals and status of attached microalgae-bacteria consortium for advanced nutrient removal from surface water. Key advantages are the various nutrient removal pathways, reduction of nutrients to very low concentration, and diversified photobioreactor configurations. Challenges include poor identification of functional species, poor control of the community composition, and long start-up times. Future research should focus on the selection and engineering of robust microbial species, mathematical modelling of the composition and functionality of the consortium, and novel photobioreactor configurations. [ABSTRACT FROM AUTHOR]