Effect of phosphate, ascorbic acid and α-tocopherol injected at one-location with tumbling on quality of roast beef

The purpose of this study was to evaluate if continuous non-vacuum or vacuum tumbling improves the quality of roast beef utilizing the one location injection. Basically, fresh roast beef treated by one location injection with tumbling had significantly different quality compared to non-tumbled ones. However, the cooked roast beef did not significantly exhibit better quality due to tumbling. There was insignificant difference of TBARS value for whole meat among treatments at day 0. The control had significantly higher TBARS value compared to roast beef with non-vacuum and vacuum tumbled samples at day 2. At 4, 7 and 14 days of refrigerated storage, the control maintained the significantly highest values when compared to the other treatments that had similar TBARS values. The addition of three antioxidants was the major contributor to lipid stability of the cooked roast beef.     

Start-up, microbial community analysis and formation of aerobic granules in a tert-butyl alcohol degrading sequencing batch reactor

We demonstrate that compact well-settling aerobic granules can be developed in a sequencing batch reactor (SBR) for the biological removal of tert-butyl alcohol (TBA) using a strategy involving step increases in TBA loading rate achieved through increasing TBA concentrations in the influent. A moderate selection pressure that included a cycle time of 24 h and a start-of-cycle TBA concentration of 100 mg/L was initially introduced to encourage the growth and retention of biomass and avoid biomass loss from hydraulic washout. Start-of-cycle TBA concentrations were increased to 150, 300, 450, and 600 mg/L on days 90, 100, 121, and 199, respectively. These increases were only introduced after complete TBA removal was accompanied by visible improvements in biomass concentration and biomass settling ability. This acclimation strategy produced incrementally higher biomass concentrations and better settling biomass with higher specific TBA biodegradation rates. Effluent TBA concentrations were consistently below the detection limit of 25 microg/L. Aerobic granules were first observed about 180 days after reactor start-up. The granules had a clearly defined shape and appearance, settled significantly faster than the suspended sludge in the reactor, and eventually became the dominant form of biomass in the reactor. The adapted granules were capable of complete TBA removal and contained a stable microbial population with a low diversity of sequences of community 16S rRNA gene fragments. This study indicates that it is possible to use aerobic granules for TBA remediation and will contribute to a better understanding of how microbial acclimation can be exploited in the SBR to biologically remove recalcitrant xenobiotics.     

Nonlinear sorption of three alcohol ethoxylates to marine sediment: a combined Langmuir and linear sorption process?

Alcohol ethoxylates (AE) are nonionic surfactants mainly used in laundry cleaning products. The relation between particle bound and freely dissolved concentrations is an important entity in risk assessment. The mechanistic understanding of AE sorption is still poor, hampering extrapolations from laboratory studies to the field. We studied the sorption of three AE with 8 EO units but with increasing alkyl chains (C10, C12, and C14) to a marine sediment. Solid-phase microextraction, using polyacrylate as the extraction phase, was applied to measure freely dissolved concentrations in pore water. A model that combines a Langmuir and a linear sorption term fitted the nonlinear sorption data to sediment well. At low aqueous concentrations, adsorption dominates over absorption leading to higher distribution coefficients for AE at low field concentrations. This dual-mode model offers the possibility to extrapolate to other AE homologues and other marine sediments and also from high to low field concentrations.     

Binding of harvested bacterial exopolymers to the surface of calcite

Biologically produced exopolysaccharides (EPS) affect calcite dissolution and precipitation. In this study, natural alkaliphilic microbial isolates were collected from biofilms on historic limestone. The isolates were screened for their ability to produce significant quantities of EPS in cultures. The most productive isolates were identified by 16S rRNA sequence analysis as a close relative of Bacillus cereus. EPS with different chemical structures were harvested from the isolates. Isothermal titration calorimetry (ITC) was used to quantify the thermodynamics of binding by the harvested EPS to calcite. The binding was described by a Langmuir adsorption isotherm. Characterization of the EPS showed that binding strength to calcite depended on the chemical nature of the polymer.     

连氮化合物在多金属硫化矿精矿分离中的应用

合理选择浮选药剂是矿物浮选分离主要手段之一。矿物浮选试验、电化学测试、IR－FT以及电子光说分析和其它方法的研究结果证实，在用氰化物作铅铜混合精矿浮选分离过程中的抑制剂时，具有连氮基因的染料可用作有效辅助抑制剂。连氮化合物的抑制效果可以通过它们与硫化铜矿物表面选择性作用来调节。莱胺黑并不吸附在方铅矿表面上，因此也没有改变方铅矿的表面性质。连氮化合物对硫化铜矿物的抑制机理是，连氮化合物通过配位机理化学吸附在硫化铜矿物表面上，形成难溶的亲水化合物。在苯胺黑存在时，氰化物浸出铜阳离子的速度减慢，矿浆中铜－氰化物比例优化，氰化物用量减少。半工业试验验证了实验室试验结果，结果表明，苯胺黑可有效地用于铅铜混合精矿分离中。在铜精矿和铅精矿中同名金属的回收率分别提高1．5％，铜清矿铜品位提高0．5％－0．7％，剧毒的氰化物用量降低50％－70％，并且浓度机溢流中溶解的金属损失减少了，改善了选矿厂周围的生态条件。     

利用煤矸石制取优质高岭土的试验研究

某煤系高岭岩系列煤矸石经干馏脱油气、脱碳、强磁选、浸出、氯化焙烧除铁、钛及增白工艺 ,制取优质高岭土取得了较理想的结果 ,且试验的重现性好、指标稳定 ,其铁、钛含量可相应降低到 1%以下 ,产品白度大于 90度。