Abundant Cyanobacteria in Autumn Adhering to the Heating, Ventilation, and Air-Conditioning (HVAC) in Shanghai.

Cyanobacteria are ever-present, mainly flourishing in aquatic environments and surviving virtually in other habitats. The microbiota of indoor dust on the pre-filter of heating, ventilation, and air-conditioning (HVAC) systems, which reflect indoor microbial contamination and affect human health, has attracted attention. Contemporary studies on cyanobacteria deposited on the pre-filter of HVAC remain scant. By the culture-independent approach of qPCR and high throughput sequencing technologies, our results documented that the cyanobacterial concentrations were highest in autumn, occurred recurrently, and were about 2.60 and 10.57-fold higher than those in winter and summer. We proposed that aquatic and terrestrial cyanobacteria contributed to the pre-filter of HVAC by airborne transportation produced by wave breaks, bubble bursts, and soil surface by wind force, owing to the evidence that cyanobacteria were commonly detected in airborne particulate matters. The cyanobacteria community structure was characterized in Shanghai, where Chroococcidiopsaceae, norank_cyanobacteriales, Nostocaceae, Paraspirulinaceae, and others dominated the dust on the pre-filter of HVAC. Some detected genera, including Nodularia sp., Pseudanabaena sp., and Leptolyngbya sp., potentially produced cyanobacterial toxins, which need further studying to determine their potential threat to human health. The present work shed new insight into cyanobacteria distribution in the specific environment besides aquatic habitats.

Abundant bacteria and fungi attached to airborne particulates in vegetable plastic greenhouses.

The proliferation of modern vegetable plastic greenhouses (VPGS) supplies more and more vegetables for food all over the world. The airborne bacteria and fungi induce more exposure opportunities for workers toiling in confined plastic greenhouses. Culture-independent approaches by qPCR and high-throughput sequencing technology were used to study the airborne particulates microbiota in typic VPGS in Shandong, a large base of vegetables in China. The result revealed the mean airborne bacteria concentrations reached 1.67 × 103 cells/m3 (PM2.5) and 2.38 × 103 cells/m3 (PM10), and the mean airborne fungal concentrations achieved 1.49 × 102 cells/m3 (PM2.5) and 3.19 × 102 cells/m3 (PM10) in VPGS. The predominant bacteria in VPGS included Ralstonia, Alcanivorax, Pseudomonas, Bacillus, and Acinetobacter. Botrytis, Alternaria, Fusarium, Sporobolomyces, and Cladosporium were frequently detected fungal genera in VPGS. A higher Chao1 of bacteria in PM10 was significantly different from PM2.5 in VPGS. The potential pathogens in VPGS include Raltonia picketti, Acinetobacter lwoffii, Bacillus anthracis, Botrytis cinerea, and Cladosporium sphaerospermum. The network analysis indicated that airborne microbiota was associated with soil microbiota which was affected by anthropologic activities. The predicted gene functions revealed that bacterial function mainly involved metabolism, neurodegenerative diseases, and fungal trophic mode dominated by Pathotroph-Saprotroph in VPGS. These findings unveiled airborne microbiomes in VPGS so that a strategy for improving air quality can be applied to safeguard health and vegetation.

Inclined algal biofilm photobioreactor (IABPBR) for cost-effective cultivation of lipid-rich microalgae and treatment of seawater-diluted anaerobically digested effluent from kitchen waste with the aid of phytohormones.

Previous study has demonstrated that freshwater can be replaced with seawater for dilution of feed to algal production and wastewater treatment, but high harvest cost in suspended-growth systems is still a troublesome limitation for large-scale production. Therefore, a novel inclined algal biofilm photobioreactor (IABPBR) was constructed for algal bioproduct production and treatment of seawater-diluted anaerobically digested effluent (SA) in this study. Fluffy polyester was selected as the best carrier for the algal biofilm among ten discarded materials. With the help of phytohormones, the viability of SDEC-18 was clearly enhanced and an algal biomass productivity of 5.66 g/m2/d was achieved. The SDEC-18 biofilm provided removal capacities of 0.65, 0.25 and 3.31 g/m2/d for TN, TP and COD. Phytohormones clearly enhanced the lipid biosynthesis, with an extraordinary lipid productivity of 3.98 g/m2/d being achieved. Moreover, an automatic harvesting system was designed for the efficient harvesting process during large-scale production.

Multiple anodic chambers sharing an algal raceway pond to establish a photosynthetic microbial fuel cell stack: Voltage boosting accompany wastewater treatment.

Photosynthetic microbial fuel cells (PMFCs) allow renewable energy production from wastewater. However, system scale-up is still a major challenge hindering the use of PMFCs for practical applications. Herein, a PMFC stack, which consisted of multiple anodic chambers installed in an algal raceway pond (ARP), was established to recovery energy from anaerobically digested effluent with the assistance of a prototypical capacitor circuit. The highest voltage output of the stack reached 1.4 V with four PMFC units and four capacitors. The system can produce stable voltages through controlling charging and discharging frequencies and the voltage output remained stable around 0.60 V when the time interval decreased to 2 s. During long-term operation, the highest power density of the stack with capacitors reached 2.34 W/m3, which was 77% higher than that without capacitors (1.32 W/m3). About 98% of the ammonium in the anolyte was removed, resulting from the ammonium migration effect. The dynamics of bacterial community compositions were not greatly influenced by the capacitor circuit, and the stack with capacitors had a more stable bacterial community compared to the stack without capacitors. The variations in bacterial community composition following power density changes indicated that members of the Clostridia and Betaproteobacteria were related to power generation. Bacteria affiliated to Bacteroidetes were inhibited when power density was high, though their numbers were enriched at the end of the process. This study promotes a practical method for developing the PMFC technology into real-world applications, and furthermore reveals the main bacteria that play vital roles in power generation by analysing the anodic bacterial community during the whole process.

Filamentous cyanobacteria triples oil production in seawater-based medium supplemented with industrial waste: monosodium glutamate residue.

BACKGROUND: To overcome the daunting technical and economic barriers of algal biofuels, we evaluated whether seawater can be a viable medium for economically producing filamentous Spirulina subsalsa as feedstock, using monosodium glutamate residue (MSGR) produced by the glutamate extraction process as an inexpensive nutrient source. RESULTS: Spirulina subsalsa cannot grow in pure seawater, but exhibited faster biomass accumulation in seawater supplemented with MSGR than in freshwater medium (modified Zarrouk medium). Introducing seawater into media ensured this cyanobacterium obtained high lipid productivity (120 mg/L/day) and suffered limited bacterial infections during growth. Moreover, the yields of protein, carotenoids and phytols were also improved in seawater mixed with MSGR. S. subsalsa exhibited high biomass and lipid productivity in bag bioreactors with 5- and 10-L medium, demonstrating the potential of this cultivation method for scaling up. Moreover, seawater can produce more biomass through medium reuse. Reused seawater medium yielded 72% of lipid content compared to pristine medium. The reason that S. subsalsa grew well in seawater with MSGR is its proficient adaptation to salinity, which included elongation and desaturation of fatty acids, accumulation of lysine and methionine, and secretion of sodium. The nutrients provided by MSGR, like organic materials, played an important role in these responses. CONCLUSION: Spirulina subsalsa has an efficient system to adapt to saline ambiance in seawater. When supplemented with MSGR, seawater is a great potential medium to produce S. subsalsa in large scale as biofuel feedstock. Meanwhile, value-added products can be derived from the ample protein and pigments that can broaden the range of biomass application and improve this biorefinery economics.

Lipid productivity in limnetic Chlorella is doubled by seawater added with anaerobically digested effluent from kitchen waste.

BACKGROUND: An economical strategy for producing microalgae as biofuel feedstock is driven by the freshwater and nutrients input. In this study, seawater was applied to limnetic algal cultivation and the behavior of algae in seawater media was observed including growth, lipid synthesis, and ultrastructure. To make seawater cater algae, a kind of wastewater, anaerobically digested effluent from kitchen waste (ADE-KW), was used as nutrient sources. RESULTS: Pure seawater cannot support the growth demand of freshwater microalga, due to high salinity and lack of nutrients. However, it is the conditions triggered the algae to synthesize lipids of 60%, double of lipid content in standard medium BG11. Introducing 3 or 5% ADE-KW (volume percentage) into seawater made algal growth reach the level attained in BG11, while lipid content compared favourably with the level (60%) in pure seawater. This method achieved the goal of fast growth and lipid accumulation simultaneously with the highest lipid productivity (19 mg/L â€Šday) at the exponential stage, while BG11 obtained 10.55 mg/L â€Šday at the stationary stage as the highest lipid productivity, almost half of that in seawater media. Moreover, the condition for highest lipid productivity enlarged algal cells compared to BG11. Under the condition for highest lipid productivity, Chlorella sorokiniana SDEC-18 had enlarged cells and increased settling efficiency compared to BG11, which facilitated harvest in an energy saving way. CONCLUSIONS: The results suggested that combining seawater with ADE-KW to cultivate microalgae had a double function: nutrients and water for algal growth, and high salinity for stimulating lipid accumulation. If this technology was operated in practice, freshwater and non-waste nutrient consumption would be completely obviated.

Phytohormone addition coupled with nitrogen depletion almost tripled the lipid productivities in two algae.

Nitrogen starvation has been an effective method to enhance the lipid content in microalgae, but low biomass means the method is far from large-scale application. In this study a combination of phytohormones, indolebutyric acid (IBA) and naphthylacetic acid (NAA), was used to verify whether phytohormones can assist two microalgae, Scenedesmus SDEC-8 and Chlorella sorokiniana SDEC-18, to resist nitrogen depletion, and achieve satisfactory biomass and lipid productivity. The two algae grew poorly but accumulated high lipid concentrations under nitrogen-depleted condition without phytohormones. However, phytohormone addition maintained the biomass concentration, and furthermore yielded lipid productivities (SDEC-8: 26.7mg/L/d, SDEC-18: 25.9mg/L/d) almost 3 times as high as those in BG11. The oxidative damage caused by nitrogen depletion could be alleviated by phytohormones. The investigation demonstrated that phytohormone supplementation simultaneously improved lipid accumulation and maintained growth of microalgae, while also optimizing the biodiesel properties compared with the tactic of nitrogen depletion alone.

The effects of algal extracellular substances on algal growth, metabolism and long-term medium recycle, and inhibition alleviation through ultrasonication.

The algal extracellular substances (AESs), mainly excreted in the lag and stationary phases, inhibited the algal growth and culture recycle. The AESs consisted of protein-like substances and saccharides, which restrained the algal lipid and protein biosynthesis. Moreover, the increasing reactive oxygen species and anti-oxidative enzymes caused by AESs led to the oxidative damage and suppressed the cell activity. The AESs affected the cells through two possible ways: one is the AESs adhered to the cell surfaces; another is the cells yielded signal molecules in response to the AESs. Fortunately, the ultrasound degraded the AESs into small molecules, which clearly alleviated the limitation and recovered the algal biomass and metabolism. This study demonstrated that ultrasonication is a promising way to alleviate the AESs, which facilitating the medium recycle for long-term continuous microalgae production.

Coupled microalgal cultivation with the treatment of domestic sewage and high-level CO2.

The ability of Scenedesmus quadricauda SDEC-13 to accumulate biomass and remove nutrients in domestic sewage from campus when incorporated with 15% CO2 was explored. The maximum specific growth rate, biomass productivity, biomass concentration, and CO2 fixation rate were 0.14 d-1, 0.08 g/L/d, 0.69 g/L, and 0.076 g-CO2/L/d, respectively. The lipid content of SDEC-13 at different culture phases was also evaluated and it increased following nutrient limitation. The removal efficiencies of total nitrogen, total phosphorus, nitrate, and ammonium were all above 90%. A coupled system was designed with hydraulic retention time of 8.33 d and biomass harvest ratio of 12%, which could yield 0.54 g/L biomass and 25% lipid content with efficient domestic sewage treatment.

Using a tubular photosynthetic microbial fuel cell to treat anaerobically digested effluent from kitchen waste: Mechanisms of organics and ammonium removal.

Anaerobically digested effluent from kitchen waste (ADE-KW) was used herein as the substrate of a tubular photosynthetic microbial fuel cell (PMFC) for power production, and also, after being diluted, as a medium for cultivation of algae in the cathodic chamber. Adding 3 mg/L phosphorus to the catholyte could efficiently enhance the algal growth and the PMFC performance. About 0.94 g/L algal biomass and 0.57 kWh/m3-ADE-KW bioelectricity were obtained from the PMFC. Soluble microbial byproduct-like material and aromatic proteins were the dominant organics in the ADE-KW, which were readily degradable in the system. About 79% of the 1550 mg/L ammonium in the anolyte transferred to the catholyte through the cation exchange membrane. The ammonium was removed mainly as electron acceptors at the cathode after being oxidized by oxygen, whereas algal assimilation only account for about 14.6% of the overall nitrogen.

The effects of combined agricultural phytohormones on the growth, carbon partitioning and cell morphology of two screened algae.

Applying phytohormones has been considered a promising way to increase lipid productivity of microalgae recently. Eight dosages of auxin phytohormones were tested to exploit the effects and mechanism of such stimulants on microalgae. The optimal one was 20mgL-1, leading to an increase in biomass concentration of 59.3% for Scenedesmus sp. SDEC-8 and 76.6% for Chlorella sorokiniana SDEC-18, meanwhile the lipid content rose from 18.74% to 56.17% (SDEC-8) and from 19.69% to 55.76% (SDEC-18). Proton pumps were activated by the stimulants, causing excretion of H+, which resulted in pH decline and a favorable condition for growth. Pigments changes implied that hormones strengthened the dark reactions of photosynthesis. Auxin addition led to a 3µm increase in diameter for C. sorokiniana SDEC-18 and altered the cellular pattern of Scenedesmus sp. SDEC-8, which improved the cells elongation. Therefore, supplement of auxin phytohormones simultaneously increased the viability and lipid production of microalgae.

Features of Golenkinia sp. and microbial fuel cells used for the treatment of anaerobically digested effluent from kitchen waste at different dilutions.

The aim of this work was to study Golenkinia sp. and microbial fuel cells (MFCs) for the treatment of anaerobically digested effluent from kitchen waste (ADE-KW) with different dilution factors. A dual-chamber MFC was fabricated for treating ADE-KW in the two chambers of the MFC and harvesting Golenkinia sp. All the anodic TN was removed more than 80%. COD removal efficiency increased from 48.2% to 76% when the dilution factor increased from 1 to 4. Maximum COD and TN removal rates were 3.56 and 3.71mg·L-1·h-1 when ADE-KW was treated without dilution in the anodic chamber. All the cathodic TN and TP removal efficiencies were approximately 90%. The highest open circuit voltage (OCV) and power density were approximately 400mV and 400mW when ADE-KW was treated directly (undiluted) in the MFC, with the highest biomass and total lipid content production of Golenkinia sp. in the cathodic chamber.

The effect of algae species on the bioelectricity and biodiesel generation through open-air cathode microbial fuel cell with kitchen waste anaerobically digested effluent as substrate.

Five strains algae (Golenkinia sp. SDEC-16, Chlorella vulgaris, Selenastrum capricornutum, Scenedesmus SDEC-8 and Scenedesmus SDEC-13) were screened as an effective way to promote recover electricity from MFC for kitchen waste anaerobically digested effluent (KWADE) treatment. The highest OCV, power density, biomass concentration and total lipid content were obtained with Golenkinia sp. SDEC-16 as the co-inoculum, which were 170mV, 6255mWm(-3), 325mgL(-1) and 38%, respectively. Characteristics of the organics in KWADE were analyzed, and the result showed that the hydrophilic and acidic fractions were more readily degraded, compared to the neutral fractions during the operation. Maximum COD and TN removal efficiency were 43.59% and 37.39% when inoculated with Golenkinia sp. SDEC-16, which were roughly 3.22 and 3.04 times higher than that of S. capricornutum. This study demonstrated that Golenkinia sp. SDEC-16 was a promising species for bioelectricity generation, lipid production and KWADE treatment.

Adjusting irradiance to enhance growth and lipid production of Chlorella vulgaris cultivated with monosodium glutamate wastewater.

Light is one of the most important factors affecting microalgae growth and biochemical composition. The influence of illumination on Chlorella vulgaris cultivated with diluted monosodium glutamate wastewater (MSGW) was investigated. Six progressive illumination intensities (0, 30, 90, 150, 200 and 300µmol·m(-2)s(-1)), were used for C. vulgaris cultivation at 25°C. Under 150µmol·m(-2)s(-1), the corresponding specific light intensity of 750×10(-6)µmol·m(-2)s(-1) per cell, algae obtained the maximum biomass concentration (1.46g·L(-1)) on the 7th day, which was 3.5 times of that under 0µmol·m(-2)s(-1), and the greatest average specific growth rate (0.79 d(-1)) in the first 7days. The results showed the importance role of light in mixotrophic growth of C. vulgaris. High light intensities of 200 and 300µmol·m(-2)s(-1) would inhibit microalgae growth to a certain degree. The algal lipid content was the greatest (30.5%) at 150µmol·m(-2)s(-1) light intensity, which was 2.42 times as high as that cultured in dark. The protein content of C. vulgaris decreased at high light intensities of 200 and 300µmol·m(-2)s(-1). The effect of irradiance on carbohydrate content was inversely correlated with that on protein. The available light at an appropriate intensity, not higher than 200µmol·m(-2)s(-1), was feasible for economical cultivation of C. vulgaris in MSGW.