Liqun Jiang

The feasibility of using complex wastewater from a monosodium glutamate factory to cultivate Spirulina subsalsa and accumulate biochemical composition

This paper is mainly observations on the growth and biomass accumulation of Spirulina subsalsa in modified Zarrouk medium supplemented with complex wastewater (CW, from a monosodium glutamate factory) in different concentrations. High ammonia in 75% and 100% CW inhibits algae growth, but maximum biomass production (2.86mgL(-1)) was obtained in 25% CW (concentration of CW in medium was 25%). Different CW concentration promoted biomass composition accumulation at different degrees, 41% of protein content in 25% CW and 18% of carbohydrate in 50% CW. In terms of economy, a concentration of 25% CW was suitable for protein production and 50% for lipid and carbohydrate production. These results suggested that CW is a feasible replacement in part for cultivation of S. subsalsa to economize input of water and nutrients.

Integrated campus sewage treatment and biomass production by Scenedesmus quadricauda SDEC-13

The notion of wastewater treatment combined with biomass production is potential and prospective. Campus sewage was utilized twice in procession to cultivate the newly isolated microalgae Scenedesmus quadricauda SDEC-13. Nutrients was efficiently removed with the phosphorus and nitrogen removal efficiency nearly 100% and more than 70% respectively in twice use of campus sewage. Ammonium was consumed rapidly within five days in 1st use. There was no significant difference in the lipid and protein content but distinct difference in their respective productivity which is ascribed to the lower biomass productivity caused by limited nutrients in 2nd use. The diverse nutrient concentration in twice use of campus sewage and BG-11 had effects on the composition of fatty acids and amino acids. SDEC-13 performed better biodiesel quality compared with BG-11 medium and produced high quality protein when cultivated in campus sewage. Finally, the campus sewage after twice use reached the corresponding discharge standard.

Effect of diethyl aminoethyl hexanoate on the accumulation of high-value biocompounds produced by two novel isolated microalgae

The low productivity of microalgae has restricted scale-up application of microalgae-based biodiesel processes. Diethyl aminoethyl hexanoate (DA-6) was investigated to enhance the biomass and metabolite productivity. At a very low concentration (10(-7)M) DA-6 made Chlorella ellipsoidea SDEC-11 and Scenedesmus quadricauda SDEC-13 obtain enlarged cell size, 114mgL(-1)d(-1), 101mgL(-1)d(-1) biomass productivity and 39.13mgL(-1)d(-1), 32.69mgL(-1)d(-1) lipid productivity, respectively. Biomass and lipid productivity of SDEC-11 and SDEC-13 were 100mgL(-1)d(-1) and 30.05mgL(-1)d(-1), 94mgL(-1)d(-1) and 28.43mgL(-1)d(-1), respectively, without DA-6. Twice hormone dose in 10(-6)M DA-6 medium resulted in higher biomass productivity (106mgL(-1)d(-1)) and longer exponential growth of SDEC-13. DA-6 also ensured the property of microalgae biodiesel to meet the EN 14214 standard. The current investigation demonstrated that DA-6 accelerated the microalgae growth and simultaneously improved the quality and quantity of lipid for biodiesel production.

Beneficial changes in biomass and lipid of microalgae Anabaena variabilis facing the ultrasonic stress environment

This study investigated the beneficial effects of ultrasonic treatment on the biomass, lipid and protein of the microalgae Anabaena variabilis. The microalgae after 11days cultivation (initial algae) were treated at the powers of 200, 350 and 500W for 10min and then cultured continuously for 3days (day 12-14). The power of 200W induced the highest lipid content 37.8% on day 12. The subsequent experiments tested the ultrasonic treatment times of 5, 10, 20 and 40min at 200W in the initial algae. The significantly improved lipid content 46.9% and productivity 54.2mg/L/d were obtained almost 1.46 and 1.86times more than that of the control algae respectively after 1day of continuous cultivation at 5min. The proper ultrasonic treatment showed the feasibility and high efficiency in promoting lipid accumulation without negatively influencing the biomass, fatty acid profiles and protein content.

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.

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.

Mutual facilitations of food waste treatment, microbial fuel cell bioelectricity generation and Chlorella vulgaris lipid production.

Food waste contains large amount of organic matter that may be troublesome for handing, storage and transportation. A microbial fuel cell (MFC) was successfully constructed with different inoculum densities of Chlorella vulgaris for promoting food waste treatment. Maximum COD removal efficiency was registered with 44% and 25 g CODL(-1)d(-1) of substrate degradation rate when inoculated with the optimal initial density (150 mg L(-1)) of C. vulgaris, which were 2.9 times and 3.1 times higher than that of the abiotic cathode. With the optimum inoculum density of C. vulgaris, the highest open circuit voltage, working voltage and power density of MFC were 260 mV, 170 mV and 19151 mW m(-3), respectively. Besides the high biodiesel quality, promoted by MFC stimulation the biomass productivity and highest total lipid content of C. vulgaris were 207 mg L(-1)d(-1) and 31%, which were roughly 2.7 times and 1.2 times higher than the control group.

Study of KOH/Al2O3 as heterogeneous catalyst for biodiesel production via in situ transesterification from microalgae

Heterogeneous KOH/Al2O3 catalysts, synthesized by the wet impregnation method with different KOH loadings (20–40 wt%) and calcination temperatures from 400°C to 800°C, were used to produce biodiesel from Chlorella vulgaris biomass by in situ transesterification. The highest yield of biodiesel of 89.53 ± 1.58% was achieved at calcination temperature of 700°C for 2 h and 35 wt% loading of KOH, and at the optimal reaction condition of 10 wt% of catalyst content, 8 mL/g of methanol to biomass ratio and at 60°C for 5 h. The characteristics of the catalysts were analysed by X-ray diffraction, scanning electron microscopy and Brunauer–Emmett–Teller.

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.

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.