Algal Consortium Research Articles

Selection of microalgae in artificial digestate: Strategies towards an effective phycoremediation

Digestate is a complex by-product of anaerobic digestion and its composition depends on the digestor inputs. It can be exploited as a sustainable source of nutrients for microalgae cultivation but its unbalanced composition and toxic elements make the use challenging. Screening algae in a simplified synthetic digestate which mimics the main nutrient constraints of a real digestate is proposed as a reproducible and effective method to select suitable species for real digestate valorisation and remediation.Growth performance, nutrient removal and biomass composition of eight microalgae exposed to high amounts of NH4+, PO4− and organic-C were assessed. Using a score matrix, A. protothecoides, T. obliquus, C. reinhardtii, and E. gracilis were identified as the most promising species. Thus, three strategies were applied to improve outcomes: i) establishment of an algal consortium to improve biomass production, ii) K+ addition to the medium to promote K+ uptake over NH4+ and to reduce potential NH4+ toxicity, iii) P starvation as pretreatment for enhanced P removal by luxury uptake.The consortium was able to implement a short-term response displaying higher biomass production than single species (3.77 and 1.03–1.89 mg mL−1 respectively) in synthetic digestate while maintaining similar nutrient remediation, furthermore, its growth rate was 1.6 times higher than in the control condition. However, the strategies aiming to reduce NH4+ toxicity and higher P removal were not successful except for single cases. The proposed algal screening and the resulting designed consortium were respectively a reliable method and a powerful tool towards sustainable real digestate remediation.

Exploring the effects of organic loading rate and domestic wastewater treatment by algal‐bacterial granules under natural daylight conditions

Algal-bacterial granules or phototrophic granules (PGs) comprising phototrophic microorganisms and bacteria are explored in wastewater treatment for achieving both environmental and economic sustainability. This study describes development of PGs and their use in biological treatment of synthetic and real domestic wastewater (sewage) under natural daylight conditions and low organic loading rate (OLR). Development of PGs was sequentially recorded in a photobioreactor operated in photo-sequencing batch reactor (photo-SBR) mode at a low OLR of 1 kgCOD.m-3 .day-1 and the developed PGs was evaluated for treating synthetic wastewater and real municipal wastewater with 0.14 kg COD m-3 .day-1 . PGs formed in the photo-sequential batch reactor (SBR) were compact and dense and exhibited excellent settling properties. The removal efficiencies were determined to be up to 95%, 93%, 97%, 72%, and 88% for turbidity, COD, TOC, NH4 + -N, and NO2 - -N/NO3 - -N, respectively. Additionally, a reduction in total viable bacterial counts and fecal coliform bacteria up to 1.7 × 103 and 7.8 × 102 cfu.mL-1 , respectively, during treatment of real municipal wastewater was achieved. This study demonstrated cultivation of algal-bacterial granules or PGs and their application for treating real municipal wastewater under natural daylight and tropical climate conditions. Further studies are needed on understanding interactions among phototrophic, autotrophic, and heterotrophic microorganisms of complex algal-bacterial consortium for emerging applications in bioremediation and wastewater treatment. PRACTITIONER POINTS: Phototrophic granules (PGs) were cultivated from algal consortium and activated sludge inoculum in photo sequencing batch reactors. Granular photobioreactor was operated at low OLR of 1 kgCOD.m3 .day-1 for developing well-settling algal-bacterial granules. PGs were stable and showed efficient biological treatment of synthetic wastewater and real sewage. Removals for turbidity, pathogens, and ammonium were at 95%, 3-log, and 72%, respectively, from real sewage.

Ultrasonication pretreatment of real-field pulping wastewater from bagasse-based paper mill

In this study an attempt has been made to evaluate the feasibility of utilizing ultrasonication as pretreatment process to treat pulping wastewater. Bio-electrochemical treatment and microalgal treatment have been used as secondary treatment process. Ultrasonication was performed in bath type sonicator at 60 kHz for various time intervals of 15, 30, 45 and 60 min. There were no significant changes in pH, TDS and COD of pulping wastewater after ultrasonication. The bio-electrochemical treatment of pretreated wastewater did not show significant improvement in treatment efficiency and color removal. Rather the MFC operating with pretreated wastewater showed poor electrochemical performance. Microalgae consortia collected from lily pond in the institute could decolorize the ultrasonically pretreated wastewater, but color of raw wastewater could not be decolorized by micro algal consortia. Ultrasonication could have modified the compounds in pulping wastewater, making them more accessible to microalgal metabolism.

Enzymatic cell disruption followed by application of imposed potential for enhanced lipid extraction from wet algal biomass employing photosynthetic microbial fuel cell

Solvent-free algal cell lysis using fungal enzyme for enhanced lipid recovery diminishes per unit production cost of algal biodiesel. In this investigation, a triple chamber photosynthetic microbial fuel cell (PMFC) was fabricated, where positive potential was imposed in the extraction chamber to draw the negatively charged lipid ions from the cathodic chamber. Under optimum imposed potential of + 3.0 V (vs standard hydrogen electrode) and with 3.5% (v/v) dosage of fungal enzyme in to the algal consortium of cathodic chamber, a maximum of 79.0% of lipid was recovered. Additionally, enzyme-assisted de-oiled algal biomass was applied in the anodic chamber to function as substrate and mediator for exo-electrogens, and the maximum power density of 10.0 W/m3 with 82.4% removal of chemical oxygen demand was achieved while treating synthetic wastewater. Therefore, this cost-effective exploration demonstrated successful bioelectricity production and concomitant wastewater treatment with solvent-free direct lipid recovery from wet algal biomass through PMFC.

Growth dependent carbon sequestration proficiency of algal consortium grown in carbon dioxide enriched simulated greenhouse

Biological carbon sequestration gaining more impetus day by day, where algae is the main backbone as a biological agent. Thus, the present study focused on the evaluation of algal biomass growth, collected from the polysheet wall of green house chamber, along with its carbon capture potentiality. The experiment were conducted in three different atmospheric conditions viz. (i) inside the green house chamber where temperature and carbon dioxide concentration was higher; (ii) in the normal atmospheric condition under full sunlight, and (iii) in closed room condition where light intensity was fixed. Maximum carbon accumulation was found (834.59±2.09 mg C/g) inside the green house chamber where mean temperature and carbon dioxide concentration were 41 °C and 705 ppm respectively. Collective effect of temperature and carbon dioxide concentration also facilitate in the maximum growth of the algal biomass (8693.68 mean number of cell/mL) in the greenhouse chamber.

Algal Consortia as the Flexible Bio-System for Wastewater Treatment: Effect of Different Light Intensities on Photosynthetic Performance, Anti-Oxidative System and Biodiesel Production of Consortia

Algal Consortia as the Flexible Bio-System for Wastewater Treatment: Effect of Different Light Intensities on Photosynthetic Performance, Anti-Oxidative System and Biodiesel Production of Consortia

Acclimation of an algal consortium to sequester nutrients from anaerobic digestate

The objective of this research was to investigate the growth, community composition, and digestate treatment performance of a local algae consortium that was adapted to bacteria-pretreated digestate. The approach was to subculture a local consortium on pretreated dairy manure digestate and then municipal wastewater sludge digestate, allowing the community to adapt before assessing its performance. The adapted consortium was then tested for growth and nutrient removal performance on the digestates and compared to the model organism, Chlorella sorokiniana. Dramatic restructuring of the consortium took place when subcultured on the digestates with Scenedesmaceae and Chlorellaceae almost completely replacing Euglena. The consortium was consistently less productive than C. sorokiniana (184 vs. 248 mg/L/d in dairy digestate and 32 vs. 48 mg/L/d in municipal digestate, P < 0.01). Pretreatment increased growth by 81% and 500% for C. sorokiniana and the consortium, respectively, in dairy digestate (P < 0.01), and allowed for algal growth in municipal digestate.

Potential application and beneficial effects of a marine microalgal biomass produced in a high-rate algal pond (HRAP) in diets of European sea bass, Dicentrarchus labrax

Microalgae have been used as live food in aquatic species. In recent years, the interest in microalgae has considerably increased, thanks to the evolution of production techniques that have identified them as an ecologically attractive aquafeed ingredient. The present study provides the first data about the effects of dietary inclusion of a microalgae consortium grown in a high-rate algal pond system on zootechnical performance, morphometric indices, and dietary nutrient digestibility as well as morphology and functionality of the digestive system of European sea bass, Dicentrarchus labrax. A dietary treatment including a commercial mono-cultured microalgae (Nannochloropsis sp.) biomass was used for comparison. Six hundred and thirty-six European sea bass juveniles (18 ± 0.28 g) were randomly allotted into 12 experimental groups and fed 4 different diets for 10 weeks: a control diet based on fish meal, fish oil, and plant protein sources; a diet including 10% of Nannochloropsis spp. biomass (100 g/kg diet); and two diets including two levels (10% and 20%) of the microalgal consortium (100 and 200 g/kg diet). Even at the highest dietary inclusion level, the microalgal consortium (200 g/kg diet) did not affect feed palatability and fish growth performance. A significant decrease in the apparent digestibility of dry matter, protein, and energy was observed in diets including 10 and 20% of the microalgal consortium, but all fish exhibited a well-preserved intestinal histomorphology. Moreover, dietary inclusion with the microalgal consortium significantly increased the enzymatic activity of maltase, sucrase-isomaltase, and ɤ-glutamil transpeptidase in the distal intestine of the treated European sea bass. Algal consortium grown using fish farm effluents represents an attempt to enhance the utilization of natural biomasses in aquafeeds when used at 10 % as substitute of vegetable ingredients in diet for European sea bass.

Removal of nutrients from domestic wastewater by microalgae coupled to lipid augmentation for biodiesel production and influence of deoiled algal biomass as biofertilizer for Solanum lycopersicum cultivation

In this study, Chlorella sp., Scenedesmus sp., and their consortium were used for the biorefinery approach. The algal consortium (Chlorella sp. + Scenedesmus sp.) grown well in 75% diluted wastewater, and obtained the highest biomass (1.78 g L−1), chlorophyll (27.03 μg mL−1), protein (175 μg mL−1) and lipid content (34.83% dry cell weight). Algal consortium showed mainly 51.75% of palmitic acid and 35.45% of oleic acid in the lipids. The removal of nitrate, ammonium, phosphate, chemical oxygen demand, total organic carbon and total nitrogen in 75% diluted wastewater by algal consortium were 96%, 98%, 95%, 83%, 86% and 94%, respectively. Moreover, deoiled algal biomass (DAB) waste used as a biofertilizer combined with inorganic fertilizer resulted in the grater improvement of Solanum lycopersicum shoot length (44%), root length (89%), fresh weight (95%), dry weight (53%), macro and micro-nutrients (N 61%, P 179%, K 71%, Ca 38%, Mg 26% and Fe 11%), and tomato yield (174%) as compared to control treatment. Our results indicate that the use of consortium is not only a potential bioresource for wastewater treatment and biodiesel production but also the DAB waste is an effective biofertilizer for sustainable agriculture production.

Phycoremediation of Heavy Metal Removal from Pharmaceutical Industrial Effluents, Kandigai, Kanchipuram District, Tamil Nadu

Water pollution occurs due to excessive releases of toxic heavy metals in urban wastewater is increasing thethreat to aquatic ecosystems. Treatment of waste water with the algae is termed as Phycoremediation which isa unique, cheap, method to treat the polluted water by a method of natural selection. Therefore, in the presentstudy effluents with an algal species were taken for Phycoremediation using five different concentrationswere used for treating pharmaceutical industrial effluents. Our research focused on microalgae Chlorellasp. and Scenedesmus sp. were used to treat the effluent at different concentrations depending upon thetolerance in severe conditions. In addition to this treatment algal consortium was also treated in the sameway. These two algal species were taken based on its predominant growth in the effluents collected. Thephysico-chemical parameters of all treated effluents were recorded in different time intervals, from 1st weekto 3rd week respectively. Chlorella and Scenedesmus sp. reduces drastically heavy metals like sulfate, lead,nickel, copper and zinc. According to the present investigation, the highest Phycoremediation was achievedin sulfate, zinc and copper. The results revealed that the above mentioned both algal species were also highlyefficient in reducing BOD, COD, TSS and TDS. In addition to this the biochemical and bio pigment analyseswere done for these two micro algal species. Therefore, this preliminary study indicates that the use of twomicroalgal sp. could be used as they are eco-friendly adsorbents in treatment of polluted wastewater.

Interaction of Chlorella vulgaris and bacteria when co-cultivated in anaerobically digested swine manure

Mono-culture and co-culture of algae (Chlorella vulgaris) and bacteria (activated sludge) on anaerobically digested swine manure (ADSM) were investigated in this research. The results showed that during the co-cultivation biomass growth was promoted (2.43 ± 0.11 g/L) compared with the algae-only culture (1.09 ± 0.03 g/L), and the aerobic bacteria growth was initially promoted, then inhibited. The SEM (Scanning Electron Microscope) observation indicated that the amount of the C. vulgaris increased while bacteria ‘disappeared’ over time. After 30 min settlement, 95.5% of the biomass in co-cultivation group precipitated, while only 40.4% of the biomass settled for the algae-only group was. It is believed that the presence of bacteria enhanced the settling rate through the formation of algal consortium flocs. Bacterial community diversity and composition were measured and the results indicated that the bacterial diversity dropped and the bacterial active classes changed in the co-cultivation group.

High methylmercury uptake by green algae in Lake Titicaca: Potential implications for remediation

Anthropogenic pressure in the high altitude lakes such as Titicaca and Uru (Bolivia) may favor the production of methylmercury (MeHg) known to accumulate in trophic chains. Periphyton associated with emerged aquatic plants (totoras) from the lake shores accumulates and demethylates MeHg providing a potential cost-effective water treatment technique. In this laboratory study, we measured the MeHg uptake kinetics of a consortium of green algae isolated from Lake Titicaca totora's periphyton. The most abundant algal consortium, composed of Oedogonium spp., Chlorella spp., Scenedesmus spp., was exposed to rising MeHg concentrations (from 5 to 200 ng·L−1) to assess their maximum potential capacity for MeHg accumulation. Various algal biomass concentrations were tested to choose the optimal one. Results provided a net MeHg uptake rate by this algal consortium of 2.38 amol ng−1·h−1·nM−1 (the total uptake was 2863 ng MeHg·g−1) for an initial concentration of 200 ng MeHg·L−1 with an algal biomass concentration of 0.02 g·L−1. This initial MeHg concentration is 1000 times higher than the one measured in the eutrophic Cohana Bay of Lake Titicaca, which shows the high accumulation potential of these green algae. Our data suggest that periphyton has a high potential for the treatment of Hg contaminated waters in constructing wetlands in the Andean Altiplano.

Performance evaluation of hydroponic system for co-cultivation of microalgae and tomato plant

Conventional hydroponic units producing disease free plants with 30–40% faster growth rate are regarded as a promising agricultural alternative in case of unfertile/metal contaminated soil. However, most nutrients in hydroponics medium remain unused and are drained off creating environmental pollution. To reduce the nutrient load and eutrophication effects, cocultivation of plant and microalgae in the hydroponic units has attracted the attention of researchers over the past few years. The present study aims to explore the influence of initial inoculum concentration of a native algal consortium over the performance of hydroponic system. Cocultivation of tomato plant with varying initial inoculum algal concentration of 0.2–0.8 mg/ml, showed that 0.8 mg/ml concentration resulted in positive interactions between microalgae and plant, with algal and plant productivity of 0.149 ± 0.024 and 0.328 ± 0.087 g/m2/d respectively after 42 days. Higher chlorophyll accumulation, along with nutritionally rich algal and plant biomass revealed lack of unwanted competition during cocultivation. Increase in dissolved oxygen during cocultivation was corroborated with efficient root respiration. Highly developed roots also provided adequate metabolic energy thus significantly increasing the nutrient uptake and accumulation, thereby reducing the nutrient load during drainage. The supernatant after algal harvesting (recycled media) supported plant growth for 24 days due to limited nutrients. Such system with microalgae symbiotically favouring plant productivity and simultaneous nutrient load reduction would ultimately support in attaining sustainable agriculture.

Efficacy of microalgal extracts as biostimulants through seed treatment and foliar spray for tomato cultivation

A probable strategy for increasing the economic sustainability of algal technology would involve the utilization of microalgal biomass as biofertilizer by off-setting the high production costs. The present study focusses on the utilization of mixed algal consortia as biofertilizer for analysing the growth rate of tomato plant. Algal extracts (20-100%) in the form of seed primer and foliar spray were used as biostimulants for the growth of tomato plant. Characterization of algal consortium showed the presence of 40.90% carbohydrates and 26.18% proteins that could potentially act as precursors for bioactive compounds to stimulate plant growth. Faster germination percentage was found with extract concentrations ranging from 20-60% in 3 days compared to the untreated seeds. Seeds treated with cellular extracts of 40% concentration also showed faster plant growth rate after sowing in terms of increase in shoot length 19.86 ± 0.51 cm and root length of 14.87 ± 0.63 cm with a fresh and dry weight of 3.47 ± 0.04 g and 0.389 ± 0.036 g respectively after 20 days. Foliar spraying of 60% algal extracts resulted in total plant height of 7.98 ± 0.19 cm with root length of 5.8 ± 0.16 cm, 46% higher compared to the control. 11 ± 0.35 leaves with chlorophyll content of 13.45 ± 0.307 mg g-1 were also obtained after 20 days, with fresh and dry biomass content of 0.416 ± 0.015 g and 0.062 ± 0.005 g respectively. Thus, microalgal cellular extracts could act as an environmental-friendly and economical alternative to synthetic liquid fertilizer for promoting sustainable agriculture.

Development of artificial consortia of microalgae and bacteria for efficient biodegradation and detoxification of lindane

Bacterial, algal and bacto-algal cultures were set up with 50 ppm lindane to study the degradation and detoxification potency of the strains. Several intermediate metabolites like pentachlorocyclohexenes, tetrachlorocyclohexenes, trichlorocyclohexane, dichlorocyclohexane, aliphatic chlorinated compounds, phenols were detected using GC–MS. It was observed that after 120 h, lindane was efficiently degraded after treatment with bacteria-algal culture. To assess the detoxification extent in different modes of lindane degradation, methyl tetrazolium (MTT) assay for cytotoxicity and 7-ethoxyresorufin-O-deethylase (EROD) assay for xenobiotics were determined using human hepato-carcinoma cell line HepG2. After 168 h treatment by bacto-algal co-culture, LC50 was increased by 1.89 folds and 3.1-fold decrease in EROD induction confirmed the reduction in toxicity. Integrated toxico-chemical analysis clearly indicated that the artificial bacterial and algal consortia could be considered as a prospective approach for degradation and detoxification of environments contaminated with lindane and other organochlorinated pesticides.

Utilization and re-use of solid and liquid waste generated from the natural indigo dye production process – A zero waste approach

The main aim of this work is focused towards possible reuse of both solid and liquid waste generated from the natural indigo dye production process. The solid waste (C/N:15.01) was utilized to produce stable compost with possible re-use in Indigofera cultivation. Among seven compost combinations (C1–C7) using jeevamrutha (JA) and cow-dung (CD) as inoculum, C4 with 8% JA showed higher biomass degradation (51%) and plant growth potential (GI > 125%). Whereas the undiluted liquid waste was treated using algal consortia, bacteria, and indigenous microbial population, achieved a maximum removal of 90% ammonia, 82% nitrate, and 88% phosphorus for its re-use in the dye production process. Hence, incorporation of suitable waste management strategies in natural indigo dye production could help to achieve a zero waste sustainable process.

Investigations on energy efficiency of biomethane/biocrude production from pilot scale wastewater grown algal biomass

Real-time studies highlighting the actual bottlenecks of microalgae-based biofuels are needed to overcome the limitations of assumption-based approach. In the present study, an algal consortium consisting of Chlorella pyrenoidosa and Phormidium, was cultivated in municipal wastewater under outdoor conditions in a pilot scale (100 L) attached biofilm reactor during January-February 2018. No energy was used to maintain the cultivation conditions (temperature, light intensity/duration). After 6 days of hydraulic retention time, the consortium showed 53–87% reduction in the nutrients’ concentrations of the selected wastewater. Consistent biomass productivity of 3.48 ± 0.44 g m−2 d−1 was observed, and its biochemical composition showed that it was rich in lipids (35.20 ± 0.63% of total solids). The wastewater grown algal biomass was subjected to anaerobic digestion at 37 °C for 30 days and hydrothermal liquefaction at 27 bars and 230 °C for 20 min to produce biomethane or biocrude, respectively. On performing the biomethane potential assay, a cumulative biomethane production of 346.59 ± 5 mL g−1 VS was observed. The theoretical methane production and stoichiometric methane potential calculated for the biomass was 504 mL g−1 VS and 591 mL g−1 VS, respectively, showing a digestibility of 58.5%. Hydrothermal liquefaction of the wastewater grown biomass gave biocrude yield of 43 ± 2% (dried biomass basis) rich in aldehydes/ketones/fatty acids. Net energy ratios for the two processes were compared. Net energy ratio for algal cultivation integrated with anaerobic digestion was found to be 0.007 and for that with hydrothermal liquefaction was found to be 0.08, proving it to be a more energy efficient process.

Treating anaerobically digested piggery effluent (ADPE) using microalgae in thin layer reactor and raceway pond

The successful cultivation of microalgae on anaerobically treated wastewaters would not only allow for the bioremediation of the waste stream but also the cost effective production of algal biomass. In this study, the growth and bioremediation ability of a microalgal consortium of Chlorella sp. and Scenedesmus sp. for treating anaerobically digested piggery effluent (ADPE) was assessed and compared using a thin layer reactor (TLR) (0.5-cm depth, 350 L) and a conventional raceway pond (15-cm depth, 1500 L) with an initial ammonium concentration of 110 ± 10 mg N-NH4+ L−1. The ammonium removal rate of microalgae grown in the TLR (19.23 mg N-NH4+ L−1 d−1) was 1.4 times higher than that grown in the raceway pond. The ash-free biomass yield (0.84 g L−1) and the average volumetric biomass productivity (60 mg L−1 d−1) of the algal consortium in the TLR were 2.5 and 2 times higher than that achieved in the raceway pond, respectively. However, considering four times higher culture volume in the raceway pond, the average areal biomass productivity in the raceway pond (4.2 g m−2 s−1) was more than two times higher than the productivity achieved in the TLR (1.9 g m−2 s−1). As a result of this, the areal lipid productivity of the microalgae grown in the raceway pond was also 2.7 times higher than that grown in the TLR. Our results indicated that under the operational conditions evaluated in this study and based on areal biomass productivity, raceway pond performed better than the thin layer reactor for treating ADPE.

Screening and enrichment of high lipid producing microalgal consortia

Lipid content is the main parameter for the evaluation of microalgae towards biodiesel production. The present study was aimed at the screening of desirable algal consortia based on lipid content for further processing into biofuel. Twenty different algal consortia were investigated for lipid content qualitatively by Nile Red and quantitatively by gravimetric method and FTIR. Nile Red is used as a fluorophore for physically characterizing the lipid body in algal cultures. The yellow fluorescence in all the samples confirmed the presence of lipid content when observed under a fluorescent microscope. Lipid contents of algal consortia estimated by gravimetry varied from 3.53–16.21%, which was higher than that assessed by FTIR analysis. FTIR spectroscopy can be used for the quantitative estimation of lipid content, protein and carbohydrate concentration. FTIR analysis of the samples revealed the presence of lipid content by virtue of methylene and methyl stretching peaks at 2800–3000 cm−1. The appearance of stretching vibrations at 1600–1700 cm−1 and 1000–1200 cm −1 obtained by FTIR spectra confirmed the presence of protein contents and carbohydrate, respectively in all the samples. Two algal consortia SM 4 and SM13 were screened out on the basis of high lipid concentration. These algal samples can be further optimized for enhanced biofuel production.

Altered Microbiome Leads to Significant Phenotypic and Transcriptomic Differences in a Lipid Accumulating Chlorophyte

Given the challenges facing the economically favorable production of products from microalgae, understanding factors that might impact productivity rates including growth rates and accumulation of desired products, for example, triacylglycerols (TAG) for biodiesel feedstock, remains critical. Although operational parameters such as media composition and reactor design can clearly effect growth rates, the role of microbe-microbe interactions is just beginning to be elucidated. In this study an oleaginous marine algae Chlorella spp. C596 culture is shown to be better described as a microbial community. Perturbations to this microbial community showed a significant impact on phenotypes including sustained differences in growth rate and TAG accumulation of 2.4 and 2.5 fold, respectively. Characterization of the associated community using Illumina 16S rRNA amplicon and random shotgun transcriptomic analyses showed that the fast growth rate correlated with two specific bacterial species ( Ruegeria and Rhodobacter spp). The transcriptomic response of the Chlorella species revealed that the slower growing algal consortium C596-S1 upregulated genes associated with photosynthesis and resource scavenging and decreased the expression of genes associated with transcription and translation relative to the initial C596-R1. Our studies advance the appreciation of the effects microbiomes can have on algal growth in bioreactors and suggest that symbiotic interactions are involved in a range of critical processes including nitrogen, carbon cycling, and oxidative stress.