Model study on CO2 removal by photobioreactor / 生物工程学报

The key point of study on CO2 removal by microalgae cultured in a photobioreactor is to improve CO2 removal capability. In this paper, a model of air-lift photobioreactor was developed by combination of conditions including the velocity of flow, the degree of mixing, the gas-liquid mass transfer and the rate of photosynthesis, and two corresponding simplified methods, such as time discretization and lumped parameters were put forward. Using a method of lumped parameters, the model for simulation of time course of DO, pH in the column air-lift photobioreactor and prediction of CO2, O2 concentrations in the outlet gas under different CO2 concentration in the aeration gas was thoroughly discussed. Experimental data were also used to verify the model which could potentially be applied to rational design of the photobioreactor, high-density culture of microalgae and efficient removal of CO2.

Screening of a triazophos-degrading strain and pathway of its degradation / 生物工程学报

A Triazophos-degrading strain, Klebsiella sp. E6, was identified by soil enrichment technology from the soil sampled from the vicinity of a factory manufacturing Triazophos (TAP). The nutrient requirement of the strain is simple. It can use TAP as the sole sources of carbon, nitrogen and phosphorus. Comparison of the degradation rates revealed that the strain degraded TAP most effectively when TAP was used as a sole nitrogen source. No inhibition effect occurred when TAP concentration was high as 1000 mg/L in the case of TAP was used as the sole nitrogen source. Analysis of the intermediates of TAP metabolism indicated that TAP is firstly hydrolyzed into 1-phenyl-3-hydroxy-1,2,4-triazole and O,O-diethyl phosphorothioic acid. 1-phenyl-3-hydroxy-1,2,4-triazole was further mineralized into inorganic compounds. A degradation pathway of TAP was proposed. The experiment results demonstrated that the strain has potential in biodegradation of TAP pollutions.

Advances on CO2 fixation by microalgae / 生物工程学报

The greenhouse effect, which is believed to occur primarily as a result of the accumulation of carbon dioxide in the atmosphere, has become one of the major environmental concerns and received worldwide attention. In this paper, algae species screening and cultivation for efficient CO2 fixation are reviewed. The related dissolved inorganic carbon (DIC) utilization form and CO2 concentration mechanism (CCM) in the process of CO2 fixation by microalgae are analyzed. Four objectives of the highly effective photobioreactor design and operation are discussed, and the advances on CO2 mitigation technology with integration of microalgae (enzyme) and membrane bioreactor are also briefly introduced. In response to elevated CO2 concentration, much attention needs to be paid to the construction of transgenic microalgae with higher performance in CO2 fixation based on the further ascertainment of the related mechanism, and the development of effective CO2 biofixation system integrated with other kinds of advanced technology, such as membrane immobilization and separation.