The feasibility of sodium hydroxide pretreatment of rice straw for solid substrate preparation to enhance laccase production by solid state fermentation.

BACKGROUND: Currently, broad industrial application of laccases is commonly restricted by the high-cost related production. Solid state fermentation (SSF) using agricultural waste is an attractively economic strategy for laccase production, yet its efficiency is low. Pretreatment of cellulosic substrate might be a vital breakpoint to solve the problem in solid state fermentation (SSF). In this study, sodium hydroxide pretreatment was involved to prepare solid substrates from rice straw. Fermentability of solid substrates in terms of carbon resource supply, accessibility and water retention value, and their influence on performance of SSF were analyzed. RESULTS: The results showed that sodium hydroxide pretreatment provided desirable solid substrates with higher enzymatic digestibility and optimal water retention value, which further facilitated the homogeneity of mycelium growth, laccase distribution and nutrition utilization during SSF. The pretreated rice straw (1 h) with diameter less than 0.085 cm gave the maximum laccase production of 2912.34 U/g, which was 7.72 times higher than the control. CONCLUSION: Hence, we proposed that enough balance between nutrition accessibility and structure support was a must for rational design and preparation of solid substrate. Additionally, sodium hydroxide pretreatment of lignocellulosic waste might be an ideal step to enhance the efficiency and lower the production cost in SSF.

IEEE VAST Challenge 2021 Winner: Visual Analytics for Spatial-Temporal Situation Awareness.

IEEE VAST Challenge 2021 provides fruitful data to test the visual analytics capability of participants. We summarize our work in this article. Trajectory data and consumption data contain a lot of information, such as consumption patterns, behavior characteristics, and so on. The information can provide favorable clues for law enforcement departments to crack a case about missing employees. We designed a visual analytics system called Sundial for spatio-temporal situation awareness with multidata fusion. It contains three views, that is, consumption view, temporal behavior view, and spatial-temporal map. With the system, analysts can effectively identify the consumption and behavior patterns of employees, and detect the suspicious activities and informal or formal relationships. Through case analysis, we illustrated how to use the system and obtain effective information.

Efficient peroxymonosulfate activation by N-rich pyridyl-iron phthalocyanine derivative for the elimination of pharmaceutical contaminants under solar irradiation.

It is of great significance for improving electron transmission performance by changing of the outer ring structure of iron phthalocyanine. Herein, 4 (pyridine-2, 3-yl) iron phthalocyanine (FepyPc), as N-rich pyridyl-iron phthalocyanine derivative, was introduced to degrade pharmaceutical contaminants. The catalytic degradation of organic pollutants with FepyPc was studied by activating peroxymonosulfate (PMS) at room temperature. The results clarified that the removal rate of carbamazepine (CBZ) was close to 100% within 60 min and the calculated apparent rate constant was about 2 times larger than FePc, which proved that FepyPc had superior performance. Four active species were identified for the degradation of CBZ, including superoxide radical (•O2-), singlet oxygen (1O2), sulfate radical (SO4•-) and hydroxyl radical (•OH). In addition, the possible reaction mechanism was inferred in FepyPc/PMS/sunlight system for CBZ removal. Finally, the CBZ degradation pathway was proposed by using ultra-performance liquid chromatography and high definition mass spectrometry (UPLC/HDMS). This research provided a meaningful and efficient method for the elimination of pharmaceutical contaminants.