Optimization of sulfate reduction and methanogenesis via phase separation in a two-phase internal circulation reactor for the treatment of high-sulfate organic wastewater.

To enhance the performance of the internal circulation (IC) reactor when treating high-sulfate organic wastewater, a laboratory-scale two-phase IC reactor with distinct phase separation capabilities was designed, and the sulfate reduction and methanogenesis processes were optimized by segregating the reactor into two specialized reaction zones. The results demonstrated that the first and second reaction areas of the two-phase IC reactor could be maintained at 4.5-6.0 and 7.5-8.5, respectively, turning them into the specialized phase for sulfate reduction and methanogenesis. Through phase separation, the two-phase IC reactor achieved a COD degradation and sulfate reduction efficiency of more than 80% when the influent sulfate concentration exceeded 5,000 mg/L, which were 32.32% and 16.04% higher than that before phase separation. Functional analyses indicated a greater activity of both the dissimilatory and assimilatory sulfate reduction pathways in the acidogenic phase, largely due to a rise in the relative abundance of the genera Desulfovibrio, Bacteroides, and Lacticaseibacillus, the primary carriers of sulfate reduction functional genes. In contrast, all the acetoclastic, hydrogenotrophic, and methylotrophic methanogenesis pathways were inhibited in the acidogenic phase but thrived in the methanogenic phase, coinciding with shifts in the genus Methanothrix, which harbors the mcrA, mcrB, and mcrG genes essential for the final transformation step of all three methanogenesis pathways.

Research on the application of the blended BOPPPS based on an online and offline mixed teaching model in the course of fermentation engineering in applied universities.

This study aimed to investigate the teaching effect of the blended BOPPPS based on an online and offline mixed teaching model ("B + BOPPPS") in the course of fermentation engineering in applied universities. The participants were 142 undergraduates majoring from the course of fermentation engineering in Food Science and Engineering in 2019 and 2020 in Huanghuai University, Zhumadian city, Henan province, China. The students in the control group (68 students) were taught in 2019, and the students in the experimental group (74 students) were taught in 2020. The traditional teaching method and "B + BOPPPS" were implemented, respectively. The teaching effect was evaluated using the questionnaire survey of course satisfaction and theoretical knowledge test. The results showed that the scores of the theoretical knowledge test in the experimental group adopting "B + BOPPPS" were significantly higher than those in the control group, and the difference was statistically significant (p < 0.01). The students had a good evaluation of the "B + BOPPPS" in many aspects, which included achieving learning goals, providing in-depth understanding of knowledge points, stimulating interest in learning, training in the ability to analyze and think about problems, and so on. The results suggested that "B + BOPPPS" could stimulate students' interest in learning and improve their subjective initiative. They could also improve students' ability to master and apply knowledge, which was conducive to improving the theoretical teaching quality of the course of fermentation engineering.

Valorization of sugarcane bagasse for sugar extraction and residue as an adsorbent for pollutant removal.

Following juice crushing for sugar or bioethanol production from sugarcane, bagasse (SCB) is generated as the main lignocellulosic by-product. This study utilized SCB generated by a hydraulic press as feedstock to evaluate sugar extraction as well as adsorption potential. Total soluble sugar (sucrose, glucose, and fructose) of 0.4 g/g SCB was recovered with H2O extraction in this case. Insoluble sugar, that is, cellulose in SCB, was further hydrolyzed into glucose (2%-31%) with cellulase enzyme, generating a new bagasse residue (SCBE). Persulfate pretreatment of SCB slightly enhanced saccharification. Both SCB and SCBE showed great potential as adsorbents with 98% of methylene blue (MB) removed by SCB or SCBE and 75% of Cu2+ by SCBE and 80% by SCB in 60 min. The maximum adsorption amount (q m) was 85.8 mg/g (MB by SCB), 77.5 mg/g (MB by SCBE), 3.4 mg/g (Cu2+ by SCB), and 1.2 mg/g (Cu2+ by SCBE). The thermodynamics indicated that the adsorption process is spontaneous, endothermic, and more random in nature. The experimental results offer an alternative to better reutilize SCB.

Efficient immobilized phospholipase A1 on Mo-basing nanomaterials for enzymatic degumming.

Six kinds of Mo-basing nanomaterials (MoO3 , MoO3 @Ru, Mo-PDA, MoPC , MoP, CNT@MoS2 ) were successfully synthesized, which were employed as carriers to immobilize phospholipase A1 (PLA1) for the hydrolysis of phospholipids (PLs). PLA1 was immobilized by a simple adsorption-precipitation-cross-linking to form an "enzyme net" covering on nanoparticles. The greatest advantage of these nanoparticles was their strong hydrophilic surface. It not only permitted their dispersion in the aqueous phase, but also showed the strong affinity for PLs in the organic phase, because amphiphilic PLs had the polar head group and higher hydrophilicity than other oils components. Michaelis-Menten analysis revealed that higher catalytic activity and enzyme-substrate affinity were observed in several immobilized PLA1 than its free form. MoO3 was confirmed to be the best candidate for carrier. The highest specific activity of MoO3 -immobilized PLA1 reached 43.1 U/mg, which was about 1.8 times higher than that of free PLA1 (24.4 U/mg). In addition, the stability and recycling were also enhanced. The robust immobilized PLA1 was prepared in this work, showing great potential for the enzymatic degumming.