An Exploratory Study of Hydrochar as a Matrix for Biotechnological Applications.

This paper explores the potentialities of hydrochar in protein separation and enzyme immobilization for non-energy biorefinery applications of hydrothermal carbonization. An innovative experimental procedure monitors soluble protein-hydrochar interactions and enzymatic reactions in a continuously stirred tank reactor. The hydrochar comes from hydrothermal carbonization of silver fir (200 °C, 30 min, 1/7 solid/water ratio) and standard activation (KOH, oven, 600 °C). Bovine serum albumin, a non-active, globular protein, was adsorbed at ≤3300 mg/g. Sip's isotherms fitted data well (R2 = 0.99999). The immobilization used a commercial ß-glucosidase, which catalyzes the hydrolysis of cellobiose to glucose, a bottleneck of the cellulose to fermentable sugar bioconversion network due to the fast enzyme deactivation. The hydrochar adsorbed ≤26 w/w% of enzyme. The heterogeneous biocatalyst operational stability was 24 times that of the soluble one. The results encourage further investigations and foreshadow process schemes coupling hydrothermal carbonization and industrial bioconversions.

Kinetic Characterization of Tar Reforming on Commercial Ni-Catalyst Pellets Used for In Situ Syngas Cleaning in Biomass Gasification: Experiments and Simulations under Process Conditions.

Filtering-catalytic candles, filled with an annular packed-bed of commercial Ni-catalyst pellets (∼600 g), were successfully tested for in situ syngas cleaning in a fluidized-bed biomass steam gasifier [Fuel Process. Technol.2019, 191, 44-53, DOI: 10.1016/j.fuproc.2019.03.018]. Those tests enabled the macroscopic evaluation of gasification and gas cleaning as a whole, requiring a more specific assessment of the catalyst performance inside the filter candle. To this end, steam reforming tests of tar key compounds (naphthalene and toluene; thiophene in traces to observe sulfur deactivation) were performed with a laboratory-scale packed-bed reactor containing the same catalyst pellets (<7 g). A lumped kinetics was derived, referred to a pseudocomponent representing tars. This was then validated by simulation of the annular catalytic packed bed inside the filter candle, obtaining numerical results in fair agreement with gasifier outputs. As a result, the lab-scale investigation with a small amount of catalyst provides reliable predictions of tar catalytic reforming in industrial-scale filtering-catalytic candles.

Steam gasification of lignite and solid recovered fuel (SRF) in a bench scale fluidized bed gasifier.

The reduction of CO2 emissions and solid waste disposal are critical issues with high importance for the environmental protection. Gasification is a promising process for sustainable energy production, because it can produce a versatile gaseous fuel starting from a wide range of organic feedstocks, and with reduced greenhouse gas emissions compared to combustion. Lignite is an abundant carbonaceous resource in Europe and in this work, gasification tests were carried out with lignite and a lignite and Solid Recovered Fuel (SRF) mixture, to evaluate the quality of gas produced from co-gasification of waste materials, in view of the final uses of the gas. Experimental gasification tests were carried out in a bench scale fluidized bed gasifier at different operating temperatures; the results were evaluated in terms of gas composition, tar content and conversion rates. In addition, characterization analyses were carried out on materials before and after the tests, and pressure fluctuation signals were analysed in order to evaluate the fluidization quality of the bed inventory.

Chronic electromagnetic field exposure decreases HSP70 levels and lowers cytoprotection.

Electromagnetic field (EMF) exposures have been shown to induce heat shock proteins (HSPs), which help to maintain the conformation of cellular proteins during periods of stress. We have previously reported that short-term exposure of chick embryos to either 60 Hz (extremely low frequency: ELF), or radio-frequency (RF: 915 MHz) EMFs induce protection against hypoxia. Experiments presented in the current report are based on a study in which long-term (4 days), continuous exposure to ELF-EMFs decreased protection against ultraviolet radiation. Based on this result, it was hypothesized that de-protection against hypoxia should also occur following long-term, continuous, or daily, repeated exposures to EMFs. To test this hypothesis, chick embryos were exposed to ELF-EMFs (8 microT) continuously for 4 days, or to ELF or RF (3.5 mW incident power)-EMFs repeated daily (20, 30, or 60 min once or twice daily for 4 days). Several of the exposure protocols yielded embryos that had statistically significant decreases in protection against hypoxic stress (continuous and 30 or 60 min ELF twice daily; or 30 or 60 min once daily RF). This is consistent with our finding that following 4 days of ELF-EMF exposure, HSP70 levels decline by 27% as compared to controls. In addition, the superposition of ELF-EMF noise, previously shown to minimize ELF-EMF induced hypoxia protection, inhibited hypoxia de-protection caused by long term, continuous ELF or daily, repeated RF exposures. This EMF-induced decrease in HSP70 levels and resulting decline in cytoprotection suggests a mechanism by which daily exposure (such as might be experienced by mobile phone users) could enhance the probability of cancer and other diseases.

Microwave exposure induces Hsp70 and confers protection against hypoxia in chick embryos.

To determine if microwave exposure could elicit a biological effect in the absence of thermal stress, studies were designed in which chick embryos were exposed to athermal microwave radiation (915 MHz) to look for induction of Hsp70, a protein produced during times of cellular stress that aids in the protection of cellular components. Levels of Hsp70 were found to increase within 2 h, with maximum expression ( approximately 30% higher than controls) typically occurring by 3 h from the start of exposure. Other embryos were exposed to microwave radiation prior to being subjected to hypoxic stress, and were found to have significantly higher survival (P < 0.05) following re-oxygenation than non-exposed controls. The results of these studies indicate that not only can athermal microwave exposures activate the stress protein response pathway; they can also enhance survivability following exposure to a subsequent, potentially lethal stress. From a public health standpoint, it is important that more studies be performed to determine if repeated exposures, a condition likely to be found in cell phone use, are still beneficial.