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Abstract: To reduce the cost of algal biomass production, mathematical model was developed for the first time to describe microalgae growth, lipid production and glycerin consumption under photoheterotrophic conditions based on logistic, Luedeking–Piret and Luedeking–Piret-like equations. All experiments were conducted in a 2L batch reactor without considering CO2 effect on algae’s growth and lipid production. Biomass and lipid production increased with glycerin as carbon source and were well described by the logistic and Luedeking–Piret equations respectively. Model predictions were in satisfactory agreement with measured data and the mode of lipid production was growth-associated. Sensitivity analysis was applied to examine the effects of certain important parameters on model performance. Results showed that S0, the initial concentration of glycerin, was the most significant factor for algae growth and lipid production. This model is applicable for prediction of other single cell algal species but model testing is recommended before scaling up the fermentation of process. [ABSTRACT FROM AUTHOR]

Abstract: High production cost is a major obstacle to the extensive use of microalgae biodiesel. To cut the cost and achieve higher biomass productivity, Chlorella minutissima UTEX2341 was cultured under photoheterotrophic conditions. With the carbon, nitrogen and phosphorus concentration of 26.37, 2.61 and 0.03gL−1 d−1 respectively, a maximum biomass productivity of 1.78gL−1 d−1 was obtained, which was 59 times more than that cultured under autotrophic condition. The lipid productivity reached 0.29gL−1 d−1, which was 11.9 times higher than the highest value reported by . The conversion rate of microalgae lipids to FAME was found to be elevated from 45.65% to 62.97% and the FAME productivity increased from 1.16 to 180.68mgL−1 d−1 after the optimization. 94% of the fatty acid of C. minutissima UTEX2341 was found to be composed of palmitic, oleic, linoleic and γ linoleic and the unsaturated fatty acids were the main parts (79.42%). [Copyright &y& Elsevier]

Abstract: In this study, the feasibility of bioflocculant extraction from backwashing sludge to reduce its production costs was investigated. Results showed that ultrasound and base treatment could significantly enhance bioflocculant extraction efficiency, however, flocculating activity was affected. It was observed that bioflocculants extracted from sludge of pH 11.0 had no flocculating activity. In contrast, bioflocculants extracted from sludge of pH 5.0, named as M-1, had good flocculating activity. To further study the flocculating activity of M-1, factors such as bioflocculant dosage, temperature and pH of the reaction solution were tested. The optimal conditions were 6.0mg/l bioflocculant dosage and pH 5.0, at a temperature of 10°C. Under these conditions, the flocculating rate of kaolin clay was 92.67%. The effectiveness of such bioflocculants in the decolorization of synthetically dyed wastewater was then examined. In flocculating methylene blue and fast blue in aqueous solutions, decolorization efficiency levels were 82.9% and 77.8%, respectively. [Copyright &y& Elsevier]

Abstract: A novel intracellular bioflocculant (named MBF-W6) produced by Chryseobacterium daeguense W6 cultured in low nutrition medium was investigated in this study. The effects of carbon source, nitrogen source, C/N ratio, initial pH, inoculum size, culture temperature and shaking speed on MBF-W6 production were studied. Chemical analysis showed that the purified MBF-W6 was mainly composed of 32.4% protein, 13.1% polysaccharide and 6.8% nucleic acid. Fourier-transform infrared (FTIR) spectroscopy indicated the presence of carboxyl, hydroxyl, and methoxyl groups. The elemental analysis of purified MBF-W6 revealed that the mass proportion of C, H, O, N and S was 40.92:6.53:44.01:8.53:1.01 (w/w) correspondingly. MBF-W6 had good flocculating rate in Kaolin suspension without any cation addition. The highest flocculating rate of 96.9% was achieved under the optimal conditions (bioflocculant dosage 1.2mgl−1, pH 5.6 and temperature 15°C). [Copyright &y& Elsevier]

Abstract: Conversion of acorn fringe extract into ellagic acid production by Aspergillus oryzae and Endomyces fibuliger were investigated. The results showed that ellagic acid production was maximized when co-fermentation of the two fungi was performed at 30°C and pH 5.0 with 5.7g/l of initial substrate concentration, which were close to the optimal values for both fungi to yield an appropriate consortium of hydrolytic enzymes. Meanwhile, it was found that the co-fermentation could compensate the deficiencies in the level of polyphenol oxidase activity from pure A. oryzae and the levels of ellagitannin acyl hydrolase and β-glucosidase activities from pure E. fibuliger, resulting in. 0.91g/l of biomass concentration containing 1.84g/l of ellagic acid. The research not only demonstrates that the co-fermentation is an effective approach to utilize forest byproduct for ellagic acid production, but also provides more evidences for understanding evolution of ellagic acid production with enzymes actions, which is important for process control of ellagic acid production in industrial application. [Copyright &y& Elsevier]