Ethanol production from agroindustrial biomass using a crude enzyme complex produced by Aspergillus niger

This study investigates ethanol production from simultaneous fermentation and saccharification (SFS) and separated hydrolysis and fermentation (SHS) using enzyme complexes produced by Aspergillus niger strains (ATCC 16404, ATCC 1057, ATCC 9029). The enzyme complexes were produced by solid-state fermentation (SSF) on inexpensive and readily available agroindustrial products: rice byproduct (composed of AFEX-treated rice rust and rice bran), whey and sugarcane bagasse. The ethanol was produced by Saccharomyces cerevisiae Y904 using whey and rice byproduct as the substrate and the enzyme complex produced by A. niger. The best result for solid-state fermentation (40 U/g of dry substrate, A. niger ATCC 16404) was obtained in a 0.5 L rotating drum bioreactor at 40 °C filled half filled with solid biomass composed of rice byproduct (86% wt/wt), whey (12% wt/wt) and CaCl₂ (2.0% wt/wt). The best result for ethanol fermentation (11.7 g/L of ethanol) was obtained after 12 h of SFS at pH 4.5 and 35 °C. A comparative study of ethanol production by Trichoderma reesei CCT 2768 and A. niger ATCC 16404 complexes under the same optimised SFS and SSF conditions was also performed, revealing that ethanol production by the A. niger enzyme complex was 2.25 times higher than that by T. reesei. These findings suggest that the ethanol production using crude enzymatic complexes produced by A. niger and agroindustrial biomass described in this paper is very promising in terms of disposal of the whey produced by cheese-making and other dairy food processing.     

Removal of acid blue 113 and reactive black 5 dye from aqueous solutions by activated red mud

Removal of acid blue 113 (AB113) and reactive black 5 (RB5) dyes from aqueous solutions by activated red mud was investigated at different reaction parameters. Activated red mud has higher removal efficiency for AB113 than that for RB5. This can be explained by a greater molecular size of RB5 than that of AB113 and by different binding affinity with the surface of the activated red mud. Equilibrium data was fitted well with Freundlich isotherm and the kinetic data followed a pseudo second-order model. Maximum adsorption capacity was 83.33 mg/g and 35.58 mg/g at pH 3 for AB113 and RB5, respectively.     

A novel joint bidding technique for fuel cell wind turbine photovoltaic storage unit and demand response considering prediction models analysis Effect's

The stake of distributed generation resources like fuel cell in daily market is proved to be a major uncertain problem. The volatile character of market price together with the unbalanced nature of power can take hold of economic advancement of distributed generation resources which in turn can culminate in diversion retribution while the market is being struck. This study introduces a market participation model in share conditions to improve the profit for Fuel Cell/wind turbine/storage/photovoltaic and demand response. To solve the mentioned problem, an accurate prediction model is presented in this paper. This model is based on complete ensemble empirical mode decomposition, and multiple artificial neural network which is coupled with Broyden water cycle algorithm. By this algorithm, the prediction accuracy of proposed forecast engine is enhanced and could get the better results. A sure-footed stochastic optimization approach was deployed in order to take prices of markets and distributed generation resources into account. In the generation of distributed generation resources, forecasting error database in everyday, modified, and depressed market was drawn on to induce probabilistic scenario. Improbable variables were discarded by a neuro-fuzzy model. Eventually, to illustrate the joint model strategy suggested in the study, a testing system contains fuel cell/wind turbine/storage unit/photovoltaic and demand response was utilized and the attained results were calculated in two different periods.     

One-step potentiostatic electrodeposition of Ni–Se–Mo film on Ni foam for alkaline hydrogen evolution reaction

Exploring efficient, abundant, low-cost and stable materials for hydrogen evolution reaction (HER) is highly desired but still a challenging task. Herein, Ni–Se–Mo electrocatalysts supported on nickel foam (NF) substrate were synthesized by a facile one-step electrodeposition method. The Ni–Se–Mo film presents high electrocatalytic activity and stability toward HER, with a low overpotential of 101 mV to afford a current density of 10 mA cm⁻² in 1.0 M KOH medium. Such excellent HER performance of Ni–Se–Mo film induced by the synergistic effects from Mo-doped Ni–Se film leads to the fast electron transfer. This work provides the validity of interface engineering strategy in preparing highly efficient transition metal chalcogenides based HER electrocatalysts.     

Volatile solids reduction in two-phase and conventional anaerobic sludge digestion

Success of two-phase anaerobic systems for primary and secondary sludge treatment has been reported based on both directly and indirectly measured volatile solids (VS) reduction, total gas and methane generation, COD reduction, etc. The objective of this research was to determine whether phase separation increases directly measured VS reduction compared to conventional anaerobic sludge digestion. Two-phase and conventional digesters were operated with sludge feeds from three sources; both 1:1 sludges (primary:waste activated, solids basis) and 100% waste activated sludges (WAS) were studied. The maximum difference between VS reductions in conventional and two-phase systems was about 8.7% with waste activated sludge. The increase in volatile solids reduction in two-phase systems with the 1:1 sludge ranged from 1.9 to 6.0% as compared to conventional systems. This relatively small increase in VS reduction may not be worth the additional cost of operating two-phase digesters at full scale.     

Enhanced anaerobic digestion of sewage sludge by thermal or alkaline-thermal pretreatments: Influence of hydraulic retention time reduction

The influence of hydraulic retention times (HRTs) reduction from 25 days to 15 days on the enhancement effects of two pretreatments (thermal pretreatment and alkaline-thermal pretreatment) on the continuous anaerobic digestion (AD) of sewage sludge was studied in a long-term experiment (196 days). The operation of the semi-continuous AD fed with raw sludge or pretreated sludge was stable at the three HRTs. The methane production increased from 70.6 to 165.8 ml/L·d to 75.2–172.6 ml/L·d and the methane yield decreased from 98.9 to 234.9 ml/g added volatile solid to 65.6–144.9 ml/g added volatile solid when the HRT reduced from 25 days to 15 days. The two pretreatments reduced the HRT of raw sludge AD by over 40%, and the effects of the alkaline-thermal pretreatment were greater than those of the thermal pretreatment. The reduction of HRT from 25 days to 15 days increased the enhancement effects of the two pretreatments on the removal of organic matter (4.7–15.9% for volatile solid), average hydrolysis ratio (36.9–116.4%), and specific hydrolysis rate (44.1–155.6%) but decreased the enhancement effects of the pretreatments on the methane production (0.9–4.6%) and yield (4.0–15.8%), average reaction ratios (0.4–8.2%), and specific rates of the last three AD steps (0.1–13.9%). The influence of HRT reduction on the enhancement effects of the alkaline-thermal pretreatment for sludge AD was slightly greater than on the enhancement effects of the thermal pretreatment.     

Intensification principle of a new three-phase catalytic slurry reactor. Part II: Eco-efficiency and techno-economic performances

In two papers, the concept and the performances of a new continuous intensified reactor named RAPTOR^® (French acronym for Reactor with Polyvalent Rectilinear Stirred Reactor with Optimised Transfer) are presented.Based on flow, heat and mass transfer characterisations and real hydrogenation experiments, Paper I presented a simple analytical model based on characteristic times that enables to explain the intensified performances compared with a semi-batch stirred reactor and to generalise the operability, rapidity and the flexibility of this minireactor. In Paper II (this article), the model is used to evaluate in a comparative study the eco-efficiency and the techno-economical advantages of a continuous process involving a RAPTOR^® versus a classical batch process equipped with a stirred reactor. Economical, environmental aspects are considered as well as productivity, safety and process control.     

Atmospheric effects on the photosensitive response of poly(methylphenylsilane) thin films

Agile ready-when-needed patterning of refractive index structures in photosensitive materials requires an understanding of the impact of local application environment on mechanisms contributing to the desired photoinduced index change. The present work examines the impact of atmosphere on the photosensitive response of poly(methylphenylsilane) (PMPS) thin films whose high photoinduced index change under low incident optical fluence make them attractive candidates for such applications. Changes in optical absorption and refractive index are investigated after exposure to ultraviolet (UV) light resonant with the lowest energy transition exhibited by the Si–Si backbone structure in the material. A comparison between photoinduced absorption changes for thin films exposed in an air atmosphere versus those observed for samples subjected to a nitrogen environment during photoexposure is made for the first time. The study reveals that the anaerobic conditions of the nitrogen atmosphere significantly reduce the photosensitive response of the material to light. These results are discussed in terms of photooxidation processes within the polysilane structure and in the context of the need for predictable photosensitive refractive index change in varied photoimprinting environments.