102,084 research outputs found
Dark fermentation of complex waste biomass for biohydrogen production by pretreated thermophilic anaerobic digestate
No full textThe Biohydrogen Potential (BHP) of six different types of waste biomass typical for the Campania Region (Italy) was investigated. Anaerobic sludge pre-treated with the specific methanogenic inhibitor sodium 2-bromoethanesulfonic acid (BESA) was used as seed inoculum. The BESA pre-treatment yielded the highest BHP in BHP tests carried out with pre-treated anaerobic sludge using potato and pumpkin waste as the substrates, in comparison with aeration or heat shock pre-treatment. The BHP tests carried out with different complex waste biomass showed average BHP values in a decreasing order from potato and pumpkin wastes (171.1±7.3 ml H2/g VS) to buffalo manure (135.6±4.1 ml H2/g VS), dried blood (slaughter house waste, 87.6±4.1 ml H2/g VS), fennel waste (58.1±29.8 ml H2/g VS), olive pomace (54.9±5.4ml H2/g VS) and olive mill wastewater (46.0±15.6ml H2/g VS). The digestate was analyzed for major soluble metabolites to elucidate the different biochemical pathways in the BHP tests. These showed the H2 was produced via mixed type fermentation pathways
Studies on conformational changes in thermophilic enzymes by means of a thermodynamic approach
No full textMechanism of propylamine-transfer reactions. Kinetic and inhibition studies on spermidine synthase from Escherichia coli
No full textKinetic mechanism of propylamine transfer reactions from different sources: S-adenosyl-1,8-diamino-3-thiooctane as a kinetic probe
No full textMechanism of protein carboxyl methyl transfer reactions: structural requirements of methyl accepting substrates.
No full textImpact of Cationic Polyelectrolyte Addition on Mesophilic Anaerobic Digestion and Hydrocarbon Content of Sewage Sludge
No full textThe agricultural spreading of treated sewage sludge is a valid strategy in terms of circular economy for the management of this nutrient-rich waste. Anaerobic digestion (AD) can be applied to stabilize and hygienize sewage sludge, making it suitable for agricultural reuse, while producing biogas to be utilized as an energy vector. However, the presence of contaminants, including petroleum hydrocarbons, could limit the widespread agricultural utilization of sewage sludge. In this context, the impact of dewatering agents, such as cationic polyelectrolytes, on AD efficiency and hydrocarbon biodegradation has been poorly investigated, although it represents a noteworthy aspect when conditioned sludge is digested for agricultural use in centralized biogas plants. This work aims to elucidate the effect of cationic polyelectrolyte addition on biomethanation as well as the degradation and extractability of C10-C40 hydrocarbons during mesophilic AD of sewage sludge. The addition of 26.7 g/kgTS of cationic polyelectrolyte was observed to extend the AD lag phase, although similar methane yields (573–607 mLCH4 per g of degraded volatile solids) were observed for both conditioned and raw sludge. Furthermore, a significant impact on hydrocarbon degradation was observed due to chemical conditioning. Indeed, this work reveals that cationic polyelectrolytes can affect hydrocarbon extractability and suggests moreover that the presence of natural interferents (e.g., biogenic waxes) in sewage sludge may lead to an overestimation of potentially toxic C10-C40 hydrocarbon concentrations, potentially limiting the application of sludge-derived digestates in agriculture
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