Jianke Huang,Bocheng Su,Xingyi Fei,Jiayi Che,Ting Yao,Ruizeng Zhang,Sanjiong Yi
Recently, using microalgae to remediate heavy metal polluted water has been attained a huge attention. However, heavy metals are generally toxic to microalgae and consequently decrease biomass accumulation. To address this issue, the feasibility of adding exogenous glucose, employing algae-bacteria system and algae-bacteria-activated carbon consortium to enhance microalgae growth were evaluated. The result showed that Cd 2+ removal efficiency was negatively correlated with microalgal specific growth rate. The exogenous glucose alleviated the heavy metal toxicity to algal cells and thus increased the microalgae growth rate. Among the different treatments, the algae-bacteria-activated carbon combination had the highest biomass concentration (1.15 g L −1 ) and lipid yield (334.97 mg L −1 ), which were respectively 3.03 times of biomass (0.38 g L −1 ) and 4.92 times of lipid yield (68.08 mg L −1 ) in the single microalgae treatment system. Additionally, this algae-bacteria-activated carbon consortium remained a high Cd 2+ removal efficiency (91.61%). In all, the present study developed an approach that had a great potential in simultaneous heavy metal wastewater treatment and microalgal lipid production.
Xiaoyu Ma,Zhen Gao,Ming Gao,Chuanfu Wu,Qunhui Wang
This study aimed to clarify the composition changes of food waste after being placed for few days and propose a two-stage fermentation method to effectively convert food waste saccharified liquid (FWSL) into lipids by Rhodosporidium toruloides . Food waste generally needs 3–5 days to be transported and stored before treatment. The lactic acid concentration of FWSL produced from 5-days-placed-at-room-temperature food waste reached to 15 g/L. Lactic acid promoted yeast proliferation, and its main mechanism was the conversion of lactic acid into pyruvic acid, which could provide energy for yeast growth through TCA cycle. The optimal lipid concentration in the two-stage fermentation reached to 9.19 g/L, and lipid yield amounted to 0.204 g lipid/g total sugar; the values increased by 44.27% and 60.63%, respectively, when compared with those in traditional fermentation. This study could provide a strategy for food waste treatment closer to industrial production.
In this study, ultrasonic/microwave-assisted extraction (UMAE), microwave-assisted extraction (UAE), ultrasound-assisted extraction (UAE), and pressurized liquid extraction (PLE) were applied to extract green coffee oil (GCO), and the physicochemical indexes, fatty acids, tocopherols, diterpenes, and total phenols as well as antioxidant activity of GCO were investigated and compared. The results indicated that the extraction yield of UMAE was the highest (10.58 ± 0.32%), while that of PLE was the lowest (6.34 ± 0.65%), and linoleic acid and palmitic acid were the major fatty acids in the GCO, ranging from 40.67% to 43.77% and 36.57% to 38.71%, respectively. A large proportion of fatty acids and phytosterols were not significantly influenced by the four extraction techniques. However, tocopherols, diterpenes, total phenols, and the free radical scavenging activity were significantly different among these four GCOs. Moreover, structural changes in the coffee residues were explored by scanning electron microscopy and Fourier transform infrared spectroscopy. Overall, the high antioxidant activity of GCO demonstrated that it can be used as a highly economical natural product in the food and agricultural industries.
危险品化学品经营许可证（带存储）