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

Abstract 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  day) at the exponential stage, while BG11 obtained 10.55 mg/L  day 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

Microwave –assisted pyrolysis aspen wood for production of valuable products under different temperatures

The valuable pyrolysis products are prepared by pyrolysis of aspen wood using microwave heating at different pyrolysis temperature. High pyrolysis temperature restrains the production of the biochar, and contributes to the generation of the bio-gas. However, pyrolysis temperature has little influenced on the yield of bio-oil. Bio-oil mainly has the phenols, hydrocarbons, ketones, aldehydes and furans compound. The phenols compound of bio-oil generated from 500 ℃ is 54%. Pyrolysis temperature influences the composition and heating value of bio-gas, and the heating value of bio-gas produced at 700 °C is 13.41 MJ/Nm3. Biochar could be used to adsorb Ag+ from wastewater, which generates value-added A/char after adsorption. Ag+ adsorption and reduction process are systematically evaluated and analyzed. The generated Ag/char is employed as the catalyst for rhodamine B degradation. Besides, Ag/char has promising application potential in energy storage

Heuristic Optimization of Culture Conditions for Stimulating Hyper-Accumulation of Biomass and Lipid in Golenkinia SDEC-16

Overproduction of biomass and hyper-accumulation of lipids endow microalgae with promising characteristics to realize the cost-effective potential of advanced bioenergy. This study sought to heuristically optimize the culture conditions on a rarely reported Golenkinia sp. The results indicate that Golenkinia SDEC-16 can withstand the strong light intensity and grow in a modified BG11 medium. The optimal culture conditions for the favorable tradeoff between biomass and lipid accumulation were suggested as follows, 25,000 lux of light intensity, 9 mM of initial nitrogen concentration, and 20 mM of initial sodium chloride concentration. Under these conditions, the biomass concentration and productivity reached 6.65 g/L and 545 mg/L/d, and the synchronous lipid content and productivity reached 54.38% and 296.39 mg/L/d. Hypersalinity significantly promoted lipid contents at the cost of biomass and resulted in an increase of cell size but loss of spines of Golenkinia SDEC-16. The results shed new light on optimizing biomass and lipid productivity

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

Abstract 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

Campus Sewage Treatment by Golenkinia SDEC-16 and Biofuel Production under Monochromic Light

The integration of microalgal cultivation in wastewater can fulfill the dual roles of pollutant degradation and biomass output. Meanwhile, the LED lights with different wavelengths have a great effect on the growth and metabolism of microalgae. In this study, Golenkinia SDEC-16, a strain isolated for biofuel production, was evaluated to verify its potentials for campus sewage treatment and lipid accumulation under the red, green, and blue lights. The results indicated that the treated campus sewage met the first grade level in the Chinese pollutant discharge standards for municipal wastewater treatment plants within seven days under both red and blue light. The green light failed to exhibit excellent performance in nutrient removal, but facilitated the lipid synthesis as high as 42.99 ± 3.48%. The increased lipid content was achieved along with low biomass accumulation owing to low effective light utilization, indicating that the green light could be merely used as a stimulus strategy. The red light benefited the photosynthesis of Golenkinia SDEC-16, with the maximal biomass concentration of 0.80 ± 0.03 g/L and lipid content of 36.90 ± 3.62%, which can attain the optimal balance between biomass production and lipid synthesis

MOESM1 of Lipid productivity in limnetic Chlorella is doubled by seawater added with anaerobically digested effluent from kitchen waste

Additional file 1: Table S1. Compositions of BG11, seawater, and anaerobically digested effluent from kitchen waste (ADE-KW). Table S2. Fatty acid profiles obtained from Chlorella sorokiniana SDEC-18 (as percentage of total fatty acid methyl esters (FAME)). Table S3. The final concentration of Chl a, ratio of Chl a/Chl b, and Carotenoids/(Chl a + Chl b) for Chlorella sorokiniana SDEC-18 grown in BG11 and in seawater supplemented with different volume percentages (0, 1, 3, 5, 8 and 15%) of anaerobically digested effluent from kitchen waste. Figure S1. Neutral lipid accumulation in Chlorella sorokiniana SDEC-18 cultivated in BG11 and seawater supplemented with different volume percentages (0, 1, 3, 5, 8 and 15%) of anaerobically digested effluent from kitchen waste. Shown are hydrocarbon oils stained using the neutral lipid-binding stain Nile Red (yellow) under a fluorescence microscope. Scale bar, 20 μm. Figure S2. The relationships of growth rate with lipid content (a), and growth rate with lipid productivity (b). The red square in graph b stands for the maximum lipid production rate calculated from the first derivative of the quadratic equation

Occupational Exposure to Polychlorinated Dibenzo‑<i>p</i>‑dioxins and Dibenzofurans, Dioxin-like Polychlorinated Biphenyls, and Polychlorinated Naphthalenes in Workplaces of Secondary Nonferrous Metallurgical Facilities in China

The concentrations of polychlorinated dibenzo-<i>p</i>-dioxins and dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (dl-PCBs), and polychlorinated naphthalenes (PCNs) were determined in workplace air from eight secondary nonferrous metal processing plants to investigate occupational exposure to these toxic compounds. The total estimated daily intakes of PCDD/Fs and dl-PCBs for workers by inhalation in the workplace were in the range of 0.15–9.91 and 0.13–8.59 pg of WHO-TEQ/kg of body weight (bw) for moderate and light activities, respectively. The daily inhalation doses for workers in the workplaces of three investigated plants exceeded the tolerable daily intake recommended by the World Health Organization. These results indicate that the risk of occupational exposure to dioxins by inhalation in the workplace of plants investigated was considerably high. For PCNs, the daily inhalation doses for workers in the workplace were in the range of 0.005–4.46 and 0.004–3.87 pg of TEQ/kg of bw for moderate and light activities, respectively, which were lower than those of dioxins. To identify the source of PCDD/Fs, PCBs, and PCNs in workplace air, their homologue profiles were compared with those in stack gas from the plants investigated. It was found that significant dioxin contamination in workplace air was mainly attributed to the emission of fugitive gas from smelting furnaces during reclamation processes