Ultrasonic-assisted enzymatic hydrolysis is a green, pollution-free and safe method for preparing porous starch. However, it is still unclear whether the thermal effect or non-thermal effect during the ultrasound process has a greater impact on the pore formation of porous starch, which determine the technical cost and choice of actual industrial production. In this study, the rice porous starch obtained by enzymatic hydrolysis (PS), ultrasonic-assisted enzymatic hydrolysis (UPS) and ice water bath ultrasonic-assisted enzymatic hydrolysis (IUPS) were compared to investigate the influence of ultrasonic thermal effect on the microstructure and physicochemical properties of rice porous starch. The results showed that the oil absorption capacities of UPS and IUPS increased by 17.66 % and 3.51 %, respectively, compared with that of PS. SEM showed that the pore-forming effect of UPS was the best, with more uniform, dense and complete pores. Compared with PS and IUPS, the pore area of UPS in the range of 50-1200 nm was significantly improved. Ultrasound-assisted enzymatic hydrolysis did not change the A-type crystal structure and basic chemical structure of starch. It shows that the thermal effect has a significant effect on the pore formation of porous starch, which can greatly help the adsorption performance.

To improve the biofilm formation efficiency and quality in a moving bed biofilm reactor (MBBR), a biofilm formation method was proposed, which employs ultrasonically disrupted sludge combined with activated sludge as inoculum. This method utilizes extracellular ATP (eATP) and DNA material released from the disrupted sludge to promote biofilm formation. The results showed that the removal efficiencies of COD, NH4+-N, and TN in terms of effluent quality were approximately 76.04 %, 74.70 %, and 75.04 %, respectively. From day 6 onwards, the biofilm biomass of the new method was significantly higher than that of the reactor inoculated solely with activated sludge (A2). On the 16th day of operation, the biofilm biomass of the new method reached 0.016 g/cm3, showing a 36.82 % increase compared to A2. Additionally, the protein and polysaccharide contents of the biofilm extracellular polymeric substances (EPS) were increased by 20.93 % and 15.11 %, respectively, compared to A2. Excitation-Emission-Matrix (EEM) spectra analysis of EPS revealed that biofilms formed by the new method contained more soluble microbial by-products and humic acid-like substances as they matured. Finally, the nitrification performance was tested, and the results showed that the new method achieved higher NH4+-N removal (76.5 %) and lower nitrate accumulation (10.76 mg/L), indicating superior biofilm nitrification and denitrification capacities. This study demonstrated that using ultrasonically disrupted sludge combined with activated sludge as inoculum is a feasible method to improve the biofilm-forming of MBBR.

Broken rice is a major by-product of the rice processing industry, while β-carotene and quercetin are bioactive compounds with health benefits but suffer from poor bioavailability, low water solubility and instability. In this study, quercetin and β-carotene were encapsulated by broken rice porous starch to form microcapsules, and their physicochemical properties, structural characteristics, stability and release profiles were analyzed using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and laser particle size analysis. The results demonstrated that encapsulation significantly enhanced photostability, increasing retention by 41 % for quercetin and 44 % for β-carotene compared to their free forms. Thermal stability at 100 °C also improved, with quercetin and β-carotene stability increasing by 44 % and 65 %, respectively. Furthermore, the encapsulated compounds exhibited sustained release properties: encapsulated quercetin showed less than 15 % gastric release (compared to 25-35 % for free quercetin) and 75 % intestinal release after 6 h (compared to 85 % for free quercetin), while encapsulated β-carotene achieved 40-50 % intestinal release (compared to 25 % for free β-carotene). The above results show that encapsulation with quercetin and β-carotene microcapsules prepared by broken rice porous starch can stabilize the functional components of food and can be used as a promising encapsulated wall material.

In order to clarify the impact of nitrogen (N) application on rice quality, meta‐analysis was utilized in this study based on rice ( Oryza sativa L.) N application data published since 2000. The effects of N application on the protein content, processing, appearance, and cooking and eating quality of rice were systematically evaluated. The results showed that the protein content of rice increased linearly with the increase of N application rate. At the same time, N application increased milled rice rate, brown rice rate, and head rice rate, and the effect was best when N application rate was 91–135 kg N ha −1 . The gel consistency, amylose content, peak viscosity, hot‐paste viscosity, and breakdown viscosity of rice were decreased by N application, and the reduction of each index was different under different N application rates. The amylose content of rice decreased with the increase of N application rate. Moreover, it was found that N application had no significant effect on chalkiness degree and chalkiness kernel rate. The results of this study can provide a reference for N application in the rice planting process to meet specific rice quality requirements.

Microwave-assisted enzymatic hydrolysis is an effective method to shorten the preparation time of porous starch. This study aims to investigate the effect of microwave treatment before/during/after enzymatic hydrolysis on the properties of porous starch. The results showed that the physicochemical properties of the porous starch obtained by microwave-assisted enzymatic hydrolysis were improved. All the samples were typical A-type crystal shapes, and the basic internal structures were the same. Among the samples, the porous starch obtained by microwave treatment during enzymatic hydrolysis (MDEPS) had the largest pore area, the highest number of pores, and significantly improved adsorption capacity, with oil and water absorption rates increased from 84.32 % to 103.1 % and 115 % to 170 % (P < 0.05), respectively. These results demonstrated that microwave treatment during enzymatic hydrolysis has great potential as a green and efficient method for preparing porous starch.

Background: Membrane biofouling is still one major obstacle in the application of membrane bioreactor (MBR). Because of similar chemical structure to quorum sensing (QS) signaling molecule autoinducer-2 (AI-2), D-ribose might be an ideal QS inhibitor to inhibit membrane biofouling. Methods: 100 mu M of D-ribose were periodically added to MBR to investigate the effect of D-ribose on membrane biofouling in MBR. Significant findings: The fouling cycle was prolonged significantly, and the membrane was covered with larger and looser foulants with the addition of D-ribose. The soluble microbial products (SMP) content were reduced slightly and the secretions of extracellular polymeric substances (EPS) in activated sludge were effectively inhibited by the addition of D-ribose. Moreover, D-ribose could promote catalase (CAT) and superoxide dismutase (SOD) activity of activated sludge, and reduce the accumulation of malondialdehyde (MDA). Furthermore, long-term addition of D-ribose could increase the abundance of quorum-sensing quenching (QQ) bacteria, strengthen the quenching ability of the system and effectively inhibit membrane biofouling.

Summary In order to improve the adsorption properties and stability of porous starch, the porous starch made from ground rice starch was doubly modified by cross‐linking and esterification using sodium trimetaphosphate (STMP) as a cross‐linking agent and octenyl succinic anhydride (OSA) as an esterifying agent. Structural analysis of the samples showed that the phosphate group in STMP formed a new P‐O‐C covalent bond with the hydroxyl group in starch by substitution, OSA combined with the hydroxyl group of starch formed an ester carbonyl group, and all cross‐linking and esterification occurred in the amorphous region of starch. DSC and TG/DTG analysis showed that STMP modification performed better than OSA modification in thermal stability. However, by analysis of the oil absorption properties and freeze–thaw stability, the OSA‐modified porous starch exhibited better oil‐holding rate and freeze–thaw stability.

D-amino acids can inhibit the formation of biofilm without affecting bacterial growth, which is a new strategy to control membrane biofouling. This paper investigated the effects of D-tyrosine on the performance of membrane bioreactor (MBR) during short-term operation. The results showed that the critical flux of activated sludge in MBR increased with the existence of D-tyrosine. The removal efficiencies of wastewater were not affected by D-tyrosine. The fouling propensities of soluble microbial products (SMP) in both MBRs were almost the same. Extracellular polymeric substance (EPS) in D-tyrosine group exhibited weaker fouling propensity. Further research indicated that the addition of D-tyrosine did not have a significant impact on SMP. D-tyrosine lead to the reduction of EPS polysaccharides and the great fluctuation of EPS protein. Microbial community analysis demonstrated that the addition of D-tyrosine changed the microbial community structure in MBR, which might be one of the reasons for the change of EPS.

This study aimed to determine the effects of D-tyrosine, D-aspartic acid, D-tryptophan and D-leucine on biofilm formation of mixed microorganisms. Results showed that, in the attachment stage, D-amino acids caused significant reduction in adhesion efficiency of mixed microorganisms to the membrane surface. Moreover, D-amino acids have a promoting effect on the reversible adhesion of mixed microorganisms. The addition of D-amino acid generally inhibited the biofilm biomass, of which D-tyrosine has the best inhibition effect. With the effect of D-tyrosine, D-aspartic acid, D-tryptophan and D-leucine, the protein in extracellular polymeric substance (EPS) decreased by 8.21%, 7.65%, 3.51% and 11.31%, respectively. The carbohydrates in EPS decreased by 29.53%, 21.44%, 14.60% and 10.54%, respectively. The results of excitation-emission matrix spectra (EEMs) suggested that the structural properties of the tyrosine-like proteins, tryptophan-like protein and humic-like acid might have changed by the D-amino acids.

Inhibition of biofilm formation can promote the operation of water system such as membrane bio-reactor. This paper investigated the effects of D-ribose on biofilm development of Escherichia coli. The results showed that the D-ribose could arrest biofilm formation of E. coli. The decrease in attached biofilm biomass reached 17.95% with 100 mu M D-ribose. Bacterial attachment experiments indicated that the attachment of E. coli to polyvinylidene fluoride membrane was inhibited with D-ribose (10 mu M to 5 mM). And the attachment was weak with the addition of D-ribose. Further research showed that 10 mu M-5 mM D-ribose could inhibit the extracellular polymeric substance (EPS) secretion of E. coli. The inhibition was obvious at 100 and 500 mu M D-ribose. Moreover, the addition of D-ribose increased superoxide dismutase and glutathione peroxidase activities, which might be the reason of EPS reduction.

The soluble (S), loosely bound (LB) and tightly bound (TB) extracellular polymeric substances (EPS) were extracted from sludge flocs of a membrane bioreactor to evaluate their characteristics and adsorptive fouling. The degrees of adsorptive fouling by the EPS fractions were in the order S-EPS < TB-EPS < LB-EPS. The images of atomic force microscopy showed the membrane fouled by LB-EPS was rougher than that fouled by the other fractions. The adsorbed EPS layer, which was sensed by quartz crystal microbalance with dissipation, was found to be more rigid and compact for LB-EPS, compared with the other EPS fractions. The excitation-emission matrix and Fourier transform infrared techniques were also used to characterize the individual EPS fractions. Compared with S-EPS and TB-EPS, the LB-EPS contained a larger amount of aromatic protein and less carbohydrates and lipids, exhibiting characteristics of greater aromaticity and hydrophobicity. These characteristics should be responsible for more severe fouling, and the stiffer and more compact structure of the adsorbed layer.

A clear identification of the fouling mechanisms in membrane bioreactor can give a better understanding on membrane fouling.In this study, early filtration behaviors of soluble microbial products (SMP) and biomacromolecules (BMM) were compared and fouling mechanisms were investigated by Hermia's model.The results suggested that intermediate blocking, standard blocking, and complete blocking occurred successively for SMP filtration while intermediate blocking and cake filtration were the main fouling mechanisms acted in succession for BMM filtration.Moreover, pore blocking made a major contribution to flux decline and resistance increase for both SMP and BMM filtration.The effective porosity was lower for BMM filtration.In addition, three-dimensional excitation-emission matrix fluorescence spectra demonstrated that the fouling layer formed by BMM was beneficial for the removal of foulants such as soluble microbial byproduct-like materials.

Microbial fuel cells (MFCs) can use nitrate as a cathodic electron acceptor for electrochemical denitrification, yet there is little knowledge about how to apply them into current wastewater treatment process to achieve efficient nitrogen removal. In this study, two dual-chamber MFCs were integrated with an aerobic membrane bioreactor to construct a novel membrane bioelectrochemical reactor (MBER) for simultaneous nitrification and denitrification under specific aeration. The effects of chemical oxygen demand (COD) loading rate, COD/N ratio, hydraulic retention time (HRT), and external resistance on the system performance were investigated. High effluent quality was obtained in the MBER in terms of COD and ammonium. During the operation, denitrification simultaneously occurred with nitrification at the bio-cathode of the MBER, achieving a maximal nitrogen removal efficiency of 84.3 %. A maximum power density of 1.8 W/m3 and a current density of 8.5 A/m3 were achieved with a coulombic efficiency of 12.1 %. Furthermore, compared to the control system, the MBER exhibited lower membrane fouling tendency due to mixed liquor volatile suspended solids (MLVSSs) and extracellular polymeric substance (EPS) reductions, EPSp/EPSc ratio decrease, and particle size increase of the sludge. These results suggest that the MBER holds potential for efficient nitrogen removal, electricity production, and membrane fouling mitigation.

The microbial fuel cell (MFC) was evaluated as an alternative way to recover electricity from canteen based food waste. Characteristics of the organics in food waste before and after the MFC treatment were analyzed to investigate how the organic matters were biodegraded and transformed during the MFC treatment. A maximum power density of 5.6W/m(3) and an average output voltage of 0.51V were obtained. During the MFC operation, the hydrophilic and acidic fractions were more readily degraded, compared to the neutral fractions. Additionally, aromatic compounds in the hydrophilic fraction were more preferentially removed than non-aromatic compounds. The MFC could easily remove the tryptophan protein-like substances in all fractions and aromatic proteins in hydrophilic and hydrophobic neutral fractions. Additionally, the hydrophobic amide-1 proteins and aliphatic components were readily hydrolyzed and biodegraded in the MFC. These findings may facilitate the pretreatment and posttreatment choices for MFC system fed with food waste.

实验主张将餐厨固体垃圾和餐厨废水分开处理,并研究微生物燃料电池(MFC)作为餐厨废水和堆肥渗滤液处理工艺的可行性,通过调节不同的有机负荷,分析其生物产电的潜力和处理效率.对于餐厨废水而言,3 000 mg/L是较为理想的处理浓度,输出电压最高,始终维持在0.5V以上;高于此浓度时电压输出特性与底物浓度呈现反相关,输出电压略低于0.5V.极化曲线,电化学阻抗分析等也都表明3 000 mg/L是较为理想的处理浓度.而且在各种浓度下经MFC处理后的餐厨废水去除率均在90％左右,出水COD均低于400 mg/L.至于堆肥渗滤液,虽然在产电性能、去除效果上较餐厨废水稍差一些,但整体上与餐厨废水呈现出相似的规律.以上结果表明,餐厨垃圾中的废水可以通过MFC有效的去除和实现能量的回收.

A hollow-fiber membrane bioreactor was integrated with a microbial fuel cell to develop a novel system of MFC–MBR based on the utilization of electricity recovered by the MFC for wastewater treatment improvement and membrane fouling mitigation in the MBR. In this system, a maximum power density of 2.18 W/m3 and an average voltage output of 0.15 V were achieved at an external resistance of 50 Ω. The removal efficiencies of COD, ammonia nitrogen (NH4+-N) and total nitrogen (TN) in the MFC–MBR were improved by 4.4%, 1.2% and 10.3%, respectively. It is worth noting that, in addition to reducing the deposition of sludge on the membrane surface by the electric field force, the MFC–MBR also alleviated the membrane fouling by sludge modification. Compared with the control MBR (C-MBR), less loosely bound extracellular polymeric substances (LB-EPS), lower SMPp/SMPc ratio, more homogenized sludge flocs and less filamentous bacteria were obtained in the MFC–MBR, which improved the dewaterability and filterability of the sludge. The cake layer on the membrane formed by the modified sludge was more porous with lower compressibility, significantly enhancing the membrane filterability. A proof of concept of an MFC–MBR was provided and shown to be effective in membrane fouling mitigation with efficient wastewater treatment and energy recovery, demonstrating the feasibility of the minute electricity generated by the MFC for membrane fouling alleviation in the MBR.

Membrane bioreactor (MBR) is an effective process for wastewater treatment, whereas the process of microbial fuel cell (MFC) can effectively degrade extracellular biological organic matter (EBOM) and recover electricity. A new process for combining MBR with MFCs was established to mitigate membrane fouling and recover electricity. The excess sludge of MBR was treated by MFCs, and then recycled to MBR. The combined system was compared with the conventional MBR with respect to the performances of wastewater treatment, the membrane fouling and the characteristics of mixed liquor. The result showed that the effluent quality of the combined system was not deteriorated significantly, with removal efficiencies of 94% and 92% for COD and NH4 +-N, respectively. Membrane fouling of the combined system was mitigated dramatically and the chemical cleaning cycle was prolonged by 28%. The ratios of mixed liquor volatile suspended solids (MLVSS) to mixed liquor suspended solids (MLSS) for the two systems were almost identical, in the range 80%~88%, indicating that the inorganics from the MFCs did not accumulate as particulates in the MBR. Loosely bound extracellular polymeric substances (LB-EPS) decreased by 48%, resulting that the sludge was modified. Lower specific resistance to filtration (2.69×1012 m/kg) and normalized capillary suction time (1.67 s·L/g MLSS) demonstrated that the dewaterability of mixed liquor in the combined system was improved.

Adsorptive fouling of microbial extracellular polymeric substances (EPS) greatly influences the fouling behavior and membrane characteristics in a membrane bioreactor (MBR). In this study, adsorptive fouling of the EPS on different membrane materials was compared and adsorptive mechanism between membranes and EPS was investigated by thermodynamic analysis. The results suggested that both the absolute and relative changes of hydraulic resistances should be considered to evaluate fouling of membranes with different materials, and Sips isotherm was the most suitable model to describe the EPS carbohydrate and protein adsorptions on membranes. Thermodynamic analysis showed that both EPS carbohydrate and protein adsorptions were spontaneous (ΔrGθ < 0), endothermic (ΔrHθ > 0), and entropy driven (ΔrSθ > 0). Decreasing ΔrGθ values with temperature suggested that EPS adsorptive fouling can be limited by reducing temperature. In addition, physisorption processes and hydrogen bonding interactions between EPS and membranes might play a relatively major role in the adsorption mechanism of EPS on the membrane surface. Atomic force microscopy (AFM) and contact angle analysis confirmed that the adsorptive fouling modified the membrane surface, making the membrane surface more heterogeneous and more hydrophobic.

This study reported a novel strategy of integrating MFCs with a membrane bioreactor (MBR) for membrane fouling mitigation. The soluble microbial products (SMP) and extracellular polymeric substances (EPS) from the suspended sludge of MFC-MBR combined system and conventional MBR were analysed. Compared to the conventional MBR, the SMP and TB-EPS concentrations in the MFC-MBR combined system increased by 8.5% and 9.2% respectively. Conversely, the LB-EPS concentration decreased by 47.5%. In addition, the aromatic protein and humic acid in LB-EPS also decreased significantly. The membrane fouling was also investigated in the conventional MBR and MFC-MBR combined system. The time required to reach a TMP of 30 kPa was 38 days in the conventional MBR and 55 days in the MFC-MBR combined system, which indicated that the recycling of the sludge treated by MFC was able to alleviate membrane fouling.

A novel combined system of sludge microbial fuel cell (S-MFC) stack and membrane bioreactor (MBR) was proposed in this study. The non-consumed sludge in the MBR sludge-fed S-MFC was recycled to the MBR. In the combined system, the COD and ammonia treatment efficiencies were more than 90% and the sludge reduction was 5.1% higher than that of the conventional MBR. It's worth noting that the energy recovery and fouling mitigation were observed in the combined system. In the single S-MFC, about 75 mg L−1 COD could be translated to electricity during one cycle. The average voltage and maximum power production of the single S-MFC were 430 mV and 51 mW m−2, respectively. Additionally, the combined system was able to mitigate membrane fouling by the sludge modification. Except for the content decrease (22%), S-MFC destroyed simple aromatic proteins and tryptophan protein-like substances in loosely bound extracellular polymeric substances (LB-EPS). These results indicated that effective wastewater treatment, sludge reduction, energy recovery and membrane fouling mitigation could be obtained in the combined system.