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This study investigated the effects of the addition of micro- (Fe, Co, Ni, and Mo) and macro-(Sulfur) nutrients on mono-digestion of sorghum under mesophilic conditions. A continuous stirred-tank reactor was operated for more than 420 days under seven different experimental conditions. The experimental results showed poor performance for methane production and process stability without nutrient supplementation. Serious deficiencies in Co and S were confirmed by nutrient analysis of dry sorghum and digestate. Nutrient augmentation efficiently enhanced methane production and volatile fatty acid (VFA) removal. Methane production reached 223 mL-CH4/g-VS, almost matching the yield predicted by biochemical methane potential (BMP) test. S was demonstrated to have a critical effect on metal availability in the digester. Consequently, to maintain stable methane fermentation, suitable supplementations of S and Co are recommended for anaerobic sorghum mono-digestion.

Given the aggravated greenhouse effect caused by CO2 and the current energy shortage, CO2 capture and reuse has been gaining ever-increasing concerns. Microbial Electrolysis Cells (MECs) has been considered to be a promising alternative to recycle CO2 bioelectrochemically to low-carbon electrofuels such as CH4 by combining electroactive microorganisms with electrochemical stimulation, enabling both CO2 fixation and energy recovery. In spite of the numerous efforts dedicated in this field in recent years, there are still many problems that hinder CO2 bioelectroconversion technique from the scaling-up and potential industrialization. This review comprehensively summarized the working principles, extracellular electron transfers behaviors, and the critical factors limiting the wide-spread utilization of CO2 electromethanogenesis. Various characterization and electrochemical testing methods for helping to uncover the underlying mechanisms in CO2 electromethanogenesis have been introduced. In addition, future research needs for pushing forward the development of MECs technology in real-world CO2 fixation and recycling were elaborated.

It is becoming increasingly urgent to investigate the partition coefficients (expressed as log KDOC values) of polybrominated diphenyl ethers (PBDEs) in dissolved organic carbon (DOC) present in wastewater. In the current study, after 72 h of equilibration, the concentrations of four common PBDEs were measured in the presence of four DOC solutions from two laboratories and two full-scale anaerobic digestion plants. Sixteen log KDOCs were determined by calculation and unit conversion. The results for the laboratory samples, such as log KDOCs for 2,2′,4,4′,5,5′-hexabromodiphenyl ether being 6.38 and 5.46 at different reaction temperatures during the cultivate procedure, suggest that a thermophilic environment promotes the solubility of PBDEs to a greater extent than mesophilic conditions. DOC composition directly influences the solubility of PBDEs, even at the same cultivating temperature: the highest log KDOCs for 2,2′,4,4′,5,6′-hexabromodiphenyl ether were 6.71 and 6.33 in different full-scale plant digestates. A linear regression with an R2 of 0.9863 was used to construct a model describing the potential relationship between log KDOC and the composition of DOC, which includes proteins, polysaccharides and lipids, and which takes into account the positions of bromine atoms, for use in predicting the log KDOC values of PBDEs in different water systems.

This study assessed the impact of swine manure (SM) dilution ratio on the microalgal biomass cultivation and further tested for biohydrogen production efficiency from the mixed microalgal biomass. At first, various solid/liquid (S/L) ratio of the SM ranged from 2.5 to 10 g/L was prepared as a nutrient medium for the algal biomass cultivation without addition of the external nutrient sources over a period of 18 d. The peak biomass concentration of 2.57 ± 0.03 g/L was obtained under the initial S/L loading rates of 5 g/L. Further, the cultivated biomass was subjected to two-step (ultrasonication + enzymatic) pretreatment and evaluated for biohydrogen production potential. Results showed that the variable amount of hydrogen production was observed with different S/L ratio of the SM. The peak hydrogen yield of 116 ± 6 mL/g TSadded was observed at the 5 g/L grown SM mixed algal biomass.

This study assessed the co-digestion of macro and microalgal biomass towards the improvement of hydrogen production. The red macroalgal biomass (Gelidium amansii) and green mixed microalgal biomass was mixed in a ratio of 8:2, with an initial substrate concentration of 10 g/L, and various amount of inoculum addition range from 3 to 15% (v/v) was evaluated to assess the feasible substrate to inoculum ratio for the effective co-digestion of the algal biomass. The results showed that the co-digestion with 6% inoculum addition provided the peak hydrogen yield of 45 mL/g dry biomass added with a high hydrogen content of 24% in the gas phase. The other tested conditions showed moderate hydrogen content in the range of 17–22%, respectively. These results suggest that anaerobic co-digestion of macro and microalgal biomass, with appropriate initial biomass loading (6%) is essential for enhanced hydrogen production.

This study investigated early stages of biofilm formation from sieved fine particles of anaerobic granules in the presence of various cationic substances using a quartz crystal sensor to improve biofilm formation in the anaerobic treatment of saline wastewater. The biomass attached on the sensor was greatly increased with Ca within the low range (8–16 mM), which was not affected by 50 mM of Na. However, the positive effect of 16 mM of Ca was strongly reduced in the co-presence of Ca and Na when Na concentrations were in the range from 25 to 150 mM because Ca may compete with Na for the limited binding sites in biofilm. The addition of cationic polymer at 150 mM of Na increased biomass adhesion by several folds at only 10–80 mg/L compared to the addition of 16 mM of Ca. Moreover, no methanogenic inhibition was presented below the polymer content of 20 mg/L.

Dewatering of waste activated sludge (WAS) is of major interest in its volume reduction, transportation and ultimate disposal. Persulfate-based oxidation process is a newly developed option for enhancing WAS dewaterability through the generation of powerful sulfate radicals (SO4−·). However, the enhancement in WAS dewaterability by persulfate differs with the species of iron catalysts used. In this study, two types of iron catalysts (i.e. Fe2+ vs. Fe0) were employed to initiate the persulfate (S2O82−), and the catalyzing behaviors and the underlying principles in enhancing WAS dewaterability were investigated and compared. The Fe2+ exhibited the high effectiveness in catalyzing the decomposition of persulfate to sulfate radicals (SO4−·), inducing the greater improvement in WAS dewatering. The WAS dewaterability (indicated by dry solids content after filtration) increased with the added S2O82−/Fe2+ dosages, with the dry solids content reaching up to 5.1 ± 0.8 wt% at S2O82−/Fe2+ dosages of 1.2/1.5 mmol/g-VS after only 30 s’ filtration, roughly 1.8-fold increase than raw WAS (1.8 ± 0.1 wt%). In contrast, the influence of the persulfate oxidation when activated with Fe0 on WAS dewaterability was statistically insignificant. The WAS dewaterability remained nearly unchanged (i.e. dry solids content of 2.0 ± 0.0 wt%), irrespective of the employed S2O82−/Fe0 dosages. Further analysis demonstrated that the WAS dewaterability negatively corresponded to loosely bound extracellular polymeric substances (LB-EPS) and tightly bound EPS (TB-EPS). The abundant SO4−· from S2O82−/Fe2+ system could effectively disrupt the gel-like EPS matrix, break apart the cells and subsequently arouse the release of the water inside EPS and cells, facilitating water-solid separation. In the case of S2O82−/Fe0, the dissolution of Fe0 particles was the rate-limiting step, due to the formation of oxide iron layer near Fe0 metallic surface, which resulted in the slow SO4−· production and thus hardly promoted WAS dewaterability. The pH adjustment could accelerate Fe0 dissolution and enhance the dewatering performance of S2O82−/Fe0 process to a certain degree, but the effect was unsatisfactory. Additionally, the observations regarding the dissolved organic matters and ammonium collectively revealed that except for enhancing WAS dewatering, S2O82−/Fe2+ oxidation could concurrently degrade COD and ammonia from WAS filtrate, lighten the burden of the subsequent sewage treatment facilities and reduce operational expense. Hence, from an environmental and economic perspective, the S2O82−/Fe2+ system possesses much greater promise for WAS dewatering.

In order to boost the economics of biogas utilization in those small facilities for food waste (FW) digestion, proximate grease trap waste (GTW) was employed to co-digest with FW. A bench-scale continuous stirred tank reactor was set up and operated at mesophilic temperature to investigate the co-digestion limit and lipid/long chain fatty acid (LCFA) conversion by increasing lipid loading stepwise. Mixing FW and GTW at lipid/total solids (TS) 55%, where the lipid loading was 1.61 g/(L·d), was proved to be appropriate, and the maximum methane yield reached 68% higher than the mono-digestion of FW, with a similar lipid reduction at approximately 90%. In addition, since acetic acid accumulation above 100 mg HAc/L had been observed under the optimal loading, the threshold value for anaerobic co-digestion of FW and GTW was confined to the lipid loading around 1.61 g/(L·d). The rapid recovery strategy of mixing the inhibited sludge with fresh inoculum at 1:4 (V/V) took effect after process failure resulted from further increasing lipid/TS to 70%. Lipid/LCFA concentrations in the effluent rose with the increased lipid loading, while palmitic acid accounted for the most percentage among the residual LCFAs, as high as 73.7% at lipid/TS 55%. Acetoclastic methanogens played an important role in accelerating process conversion, due to the fact that raising GTW addition led to the increased methanogenic activity, with a value of 26.9 mL-CH4/(g-VS·d) at the optimal loading.

The effects of organic loading rate (OLR) and operating temperature on the performance of siphon-driven self-agitated anaerobic reactor (SDSAR) in an on-site food waste (FW) treatment system were investigated. Two reactors were operated in parallel for comparison between mesophilic condition (35 ± 1 °C) and thermophilic condition (55 ± 1 °C). With HRT above 15 d and OLR below 4.8 kg-COD/m3/d, relatively high COD removal in the range of 84.5–92.3% was obtained in both reactors. The limits of the loading capacity of the mesophilic SDSAR were observed when OLR was further increased to 7.3 kg-COD/m3/d by shortening HRT. Blocking and gas production reduction occurred and COD removal decreased sharply to 75.9% in the mesophilic reactor. In contrast, the thermophilic reactor can be operated at this OLR with satisfactory COD removal and biogas production. Furthermore, at OLR of 14.4 kg-COD/m3/d, the COD removal was maintained as high as 87.5% in the thermophilic reactor. The conversion of influent COD to methane was maintained above 80% at all the OLR applied in both reactors. The results of this study indicated that thermophilic SDSAR is preferred for the on-site FW treatment.

In this pilot-scale study, an innovative mainstream treatment process that couples the anaerobic membrane reactor (AnMBR) with a one-stage PN/A system was proposed for advancing the concept of carbon neutrality in the municipal wastewater treatment plant. This work demonstrates the start-up procedure of a pilot-scale one-stage PN/A system for mainstream treatment. The 255-day start-up of the one-stage PN/A system involved the cultivation of ammonium-oxidizing bacteria (AOB) from the activated sludge, suppression of nitrite-oxidizing bacteria (NOB), investigation of in-situ growth kinetics of anammox bacteria (AnAOB), and the 50-day operation of the pilot-scale AnMBR-PN/A process for natural mainstream treatment. It is verified in the pilot-scale system for the first time that the in-situ free ammonia (FA) and free nitrous acid (FNA) exposure could effectively eliminate the Nitrospira (the NOB genus) while retaining the Nitosonomas (the AOB genus) community in the suspended sludge. NOB community rebounding was not detected even at the mainstream conditions with low nitrogen concentrations (Influent ammonium concentration=38±6 mg-NH4+-N/L) by intermittent aeration to control the system dissolved oxygen (DO) below 0.5 mg/L. The results of the mainstream treatment showed that the average effluent total nitrogen (TN) in the coupled process was generally lower than 10 mg-N/L, which meets the discharge limits of most prefectures in Japan. The investigated results of the in-situ anammox bacteria (AnAOB) growth kinetics suggested that the promoted start-up strategy of taking advantage of the warm months with higher mainstream temperature to achieve the rapid in-situ growth of the AnAOB is applicable in the investigated regions. From the perspective of the removal performance of the TN and organic substance, the AnMBR-PN/A process has great potential as the layouts of the carbon-neutral mainstream wastewater treatment plants.

This study investigated the effect of combination of pretreatment methods such as ultra-sonication and electrolysis for the minimum energy input to recover the maximal carbohydrate and solubilization (in terms of sCOD) from mixed microalgae biomass. The composition of the soluble chemical oxygen demand (COD), protein, carbohydrate revealed that the hydrolysis method had showed positive impact on the increasing quantity and thus enhanced methane yields. As a result, the combination of these 2 pretreatments showed the greatest yield of soluble protein and carbohydrate as 279 and 309mg/L, which is the recovery of nearly 85 and 90% in terms of total content of them. BMP tests showed peak methane production yield of 257mL/gVSadded, for the hydrolysate of combined pretreatment as compared to the control experiment of 138mL/gVS added.

This research investigated the effects of various dilute acid (HCl, H 2 SO 4 , HNO 3 , H 3 PO 4 ) pretreatment on the solubilization of marine macroalgal biomass Gelidium amansii and subsequent hydrogen fermentation in a batch vials. The dry grounded biomass was hydrolyzed at temperature of 121 °C, solid/liquid (S/L) ratio of 5% (w/v), dilute acid concentration (1%) of various reagents, and reaction time of 30 min. The hydrolyzates obtained at these conditions were then fed to batch hydrogen fermentation. Results revealed that only H 2 SO 4 pretreatment method had a significant effect on improvement of biohydrogen production from Gelidium amansii , whereas the other pretreatment conditions were even worse than the control experiment. Dilute sulfuric acid (1%) provided a maximum hydrogen production of 52 mL-H 2 /g-dry biomass, whereas control experiment provided a hydrogen efficiency of 27 mL-H 2 /g-dry biomass. The results showed that selection of appropriate pretreatment method is essential for enhanced hydrogen production from macroalgal biomass.

Anaerobic digestion of decabromodiphenyl ether was carried out and compared in two continuously stirred anaerobic bioreactors for 210 days under thermophilic and mesophilic conditions. Results show that the degradation of decabromodiphenyl ether followed the first-order reaction kinetics, which exhibited a higher removal rate in the thermophilic reactor when compared to the mesophilic one, reaching its maximum of 1.1 μg·day−1. The anaerobic digestion of decabromodiphenyl ether was found to involve the replacement of bromines from polybrominated diphenyl ether by hydrogen atoms, gradually forming nona-, octa- and hepta-brominated diphenyl ether, respectively. Under the thermophilic condition, the reactors were dominated by Bacillus sp. and Methanosarcina sp. with high bioactivity and high concentrations of debromination microorganisms.

The application of biofilm-based processes such as up-flow anaerobic sludge blanket (UASB) reactors for saline wastewater treatment faces the problems of low strength and stability of granules cause by high salt concentration. In this study, the effect of biochar/Fe addition on biofilm formation was examined in anaerobic treatment of high salinity (10 g-Na+/L) wastewater with two parallel lab-scale UASBs. Higher removal efficiencies of soluble influent organics and methane production were achieved in the biochar/Fe seeded UASB reactor with an organic loading rate (OLR) ranging from 2.5 to 10 g-COD/L/d. The average SS concentration of the granular sludge in the biochar/Fe seeded UASB reactor reached 21.6 g/L while that in the non-biochar/Fe-seeded UASB one was 16.4 g/L. A higher extracellular polymeric substances (EPS) of 91.1 mg/g-VSS and medium particle size (D50) of 63.2 µm in the granular sludge with biochar/Fe addition were observed. All these results suggest that biochar/Fe addition can effectively improve biofilm formation under high salinity conditions.

This study investigated the potential and possibility of three mixed microalgae consortia collected from various ecological niches towards bioenergy production of H 2 and CH 4 in batch experiments under mesophilic conditions. Three different consortia collected from wastewater treatment plant, in an open pond system and in the lake bed possess different compositions and characteristics during their growth under a light intensity of 8000 lux and are referred as OP1, OP2 and LB. After 40 days of cultivation, collected wet biomass is directly used for H 2 and CH 4 fermentation and the results indicated that, consortia OP1 is good for H 2 production whereas consortia OP2 and LB showed nearly the similar CH 4 production performances. Peak hydrogen production rate (HPR) and methane production rate (MPR) were achieved as 289 mL/L-d and 97 mL/L-d, respectively from consortia OP1 and OP2. The energy production from this process could significantly contribute towards CO 2 emission reduction. Besides, this approach could be helpful in choosing the consortia towards which kind of biofuel (either H 2 or CH 4 ) production.

Biohydrogen production from lignocellulosic biomass (LCB) is an active research area. Several workers have tested a number of substrates under different operational conditions and brought forward the many positive process performance features and identified the main sources of inhibition. This review analyzes selected fermentative biohydrogen production processes by revisiting the core biohydrogen production performances in terms of gas production rates and yields and equally addresses the options for process enhancement by the application of through pretreatment methods and detoxification of process inhibitors. In addition, the issues related to continuous biohydrogen operation in different reactor configurations are highlighted. Lastly, future avenues of research which may be engendered and engineered to enhance the biohydrogen generation and process biokinetics are discussed. This review intends to provide the fundamental understanding of biohydrogen production and provides a perspective on future developments in this area of applied research.

The dispersion of granules in upflow anaerobic sludge blanket (UASB) reactor represents a critical technical issue in methanolic wastewater treatment. In this study, the potentials of coupling a microbial electrolysis cell (MEC) into an UASB reactor for improving methanolic wastewater biodegradation, long-term process stability and biomethane recovery were evaluated. The results indicated that coupling a MEC system was capable of improving the overall performance of UASB reactor for methanolic wastewater treatment. The combined system maintained the comparatively higher methane yield and COD removal efficiency over the single UASB process through the entire process, with the methane production at the steady-state conditions approaching 1504.7 ± 92.2 mL-CH4 L−1-reactor d−1, around 10.1% higher than the control UASB (i.e. 1366.4 ± 71.0 mL-CH4 L−1-reactor d−1). The further characterizations verified that the input of external power source could stimulate the metabolic activity of microbes and reinforced the EPS secretion. The produced EPS interacted with Fe2+/3+ liberated during anodic corrosion of iron electrode to create a gel-like three-dimensional [-Fe-EPS-]n matrix, which promoted cell-cell cohesion and maintained the structural integrity of granules. Further observations via SEM and FISH analysis demonstrated that the use of bioelectrochemical stimulation promoted the growth and proliferation of microorganisms, which diversified the degradation routes of methanol, convert the wasted CO2 into methane and accordingly increased the process stability and methane productivity.

Restaurant grease trap waste (GTW) is a potentially feasible energy source that can be used as an alternative to liquid fossil fuels and natural gas. However, GTW must be collected from many different resources for energy production because restaurants in Japan only produce an average of 486 kg GTW per year. This study investigated the variation in oil properties and methane generation potential of 44 GTW samples from 13 types of restaurants during different seasons. The GTW samples had high variation in oil content and oil properties. Biofuel oil was extracted from most GTW samples at a high efficiency (more than 80 wt%). In contrast, the methane yield varied little among de-oiled GTW samples. All types of GTWs are potential sources of biomethane generation. GTW samples are classified into five major oil property clusters according to solid chemical stability. Oil properties depend little on the season and heavily on the restaurant type.

This study investigated the effects of pretreatment methods (such as autoclave, ultrasonication and electrolysis) of mixed microalgae consortia (predominantly composed of Scenedesmus followed by Chlorella species) from natural ecological niche. In addition, the cultivated biomass (wet) was subsequently utilized for fermentative H2 production in mesophilic regime. The results showed that peak hydrogen production rate (HPR) and hydrogen yield (HY) were achieved from electrolysis pretreated algal consortia as 236 ± 14 mL/L-d and 37.7 ± 0.4 mL/g (volatile solids) VSadded, whereas the untreated algal consortia resulted in the turnout as 64 ± 5 mL/L-d and 9.5 ± 0.0 mL/g VSadded, respectively. The significant increment observed in HPR and HY values were nearly 4 times higher. The solubilization of organic matter during the pretreatment showed positive correlation with the H2 production. The energy generation rate and yield of the corresponding pretreatment methods were as follows, 1.44, 1.79 and 2.65 kJ/L-d for autoclave, ultra-sonication and electrolysis, the corresponding yields also fell in the range of 0.32, 0.41 and 0.43 kJ/g VSadded, respectively.

Nowadays there is a huge demand for new and sustainable technologies aiming the reduction of the greenhouse gas, in particular carbon dioxide emission. In this work, enzymatically-boosted supported ionic liquid membrane (EB-SILM) was developed to permeate carbon dioxide with improved efficiency. Firstly, the selected biocatalyst, carbonic anhydrase (CA) was prepared and purified from spinach, a cheap plant biomass containing the enzyme of our interest. Afterwards, the CA enzyme preparation was used for SILM fabrication in order to test the properties towards enhanced carbon dioxide permeation over CH 4 , H 2 and N 2 . The results indicate basically that EB-SILMs possess an increased ability to permeate CO 2 in comparison with enzymeless controls and therefore, may be viewed as a promising approach e.g. towards enhanced CO 2 -capture bioprocesses.

Highlights • Anaerobic digestion (AD) of radiocesium (RCs)-contaminated crops was investigated. • Anaerobic degradation of crops releases RCs into aqueous phase of digestate. • RCs-solubilization efficiency rose with increase in degradability of feedstocks. • Solid-liquid partition coefficient widely varied depending on the types of adsorbents. • 90 % of RCs removal was achieved at 30 g-zeolite/L or 1 g-Prussian blue beads/L., Cultivation of biomass crops for energy production is a promising land-use for farmland abandoned owing to radionuclide fallout. However, radionuclides in soil are easily taken up in the crop. To understand phase partitioning of radiocesium Cs (RCs) during anaerobic digestion (AD) of crops, semi-continuous AD experiments were carried out using two types of RCs-contaminated crops. Analysis of fractionated digestate effluent revealed that AD of the crops released RCs into the water phase (up to 82 %), and the efficiency of RCs solubilization depended on crop biodegradability. Adsorption treatment for removal of RCs from the water phase of the digestate indicated a water–zeolite partition coefficient of 0.287 L/g. The efficiency of removal from the water phase was 90 % at an adsorbent dose of 30 g/L.

The use of liquid fraction of pressed municipal solid waste (LPW) for hydrogen production was evaluated via electrohydrogenesis in a single-chamber microbial electrolysis cell (MEC). The highest hydrogen production (0.38 ± 0.09 m3 m−3 d−1 and 30.94 ± 7.03 mmol g−1 CODadded) was achieved at an applied voltage of 3.0 V and pH 5.5, increasing by 2.17-fold than those done at the same voltage without pH adjustment (pH 7.0). Electrohydrogenesis was accomplished by anodic oxidation of fermentative end-products (i.e. acetate, as well as propionate and butyrate after their acetification), with overall hydrogen recovery of 49.5 ± 11.3% of CODadded. These results affirm for the first time that electrohydrogenesis can be a noteworthy alternative for hydrogen recovery from LPW and simultaneous organics removal. Electrohydrogenesis efficiency of this system has potential to improve provided that electron recycling, electromethanogenesis and deposition of non-conductive aggregates on cathode surface, etc. are effectively controlled.

Continuous primary energy consumption has motivated the scientists of the world to search for renewable energy sources that could substitute fossil fuels. Microalgae can be an alternative substrate for renewable energy recovery. In this study, biochemical methane potential (BMP) assays were used as a tool to examine the technical potential of methane production from microalgae (MA) through co-digesting with food waste (FW) at different MA: FW ratios on volatile solids (VS). Three mathematical models (i.e. first-order kinetic, modified Gompertz, and Cone models) were also utilized to fit the experimental data, with the purpose of elucidating the biological degradation and principle kinetics of the co-digestion. The results showed that supplementing food waste significantly improved microalgae digestion performance, with the highest methane yield of 639.8 ± 1.3 mL/g VSadded obtained at a MA:FW ratio of 0.2:0.8, which was 4.99-fold increase with respect to that (106.9 ± 3.2 mL/g VSadded) of the microalgae alone. Cone model had the best fitness and reliability to the experimental results and could describe the co-digestion kinetics more reasonably. Parameter analysis and synergistic impact evaluation together revealed that the improvement in methanogenesis potential (fd) caused by the synergy of co-digestion might be the fundamental cause for the upgraded methane production. These results validated the superiority of co-digestion as a step towards maximizing methane production from microalgae, aiding the development of multi-biomass co-disposal and ultimately bioenergy recovery techniques.

This review portrays the status and perspectives of bioaugmented hydrogen fermentation, an emerging strategy of process intensification. Firstly, the paper introduces the potentials and limitations of dark fermentative hydrogen production and describes the technologies available for its enhancement including bioaugmentation. The theoretical background and practical features of augmentation methods for biohydrogen generation are subsequently assessed and surveyed in details. Furthermore, a throughout evaluation of the recent and novel achievements reported in the concept of “augmented hydrogen fermentation” is given in association with (i) bioreactor start-up, (ii) utilization of solid wastes, wastewaters, (iii) the feasibility in continuous systems as well as in complementary – integrated – applications. The article is intended to provide an insight to the advancements made for realizing more viable biohydrogen formation via bioaugmentation and hence it might be encouraging for further studies in the field.

This study investigated the effect of controlling pH (5.5) and heat pre-treatment of seed inoculum in dark fermentative hydrogen production. The results showed that only inoculum source plays an important role rather than pH and heat treatment. Seed source is vital factor despite, heat treatment and pH controlled at 5.5. Mesophilic fermentation resulted in CH4 generation, however, thermophilic fermentation while using thermophilic inoculum is opted for H2 generation. In contrast promoted mesophilic inoculum (mesophilic to thermophilic) still documented for CH4 generation. Peak hydrogen production rate (HPR) and methane production rate (MPR) were noted as 90 and 117 mL/L-d, during the conditions of thermo inoculum (thermophilic, pH 5.5) and pH no control (mesophilic) experiments, respectively. Peak, total solids (TS) and chemical oxygen demand (COD) removal were achieved as 56 and 42% at mesophilic condition. Volatile fatty acid (VFA) profiling revealed the background of the process performances. Microbial community analysis via fluorescent in-situ hybridization (FISH) narrated that bacteria and archaea communities were enriched during thermophilic and mesophilic experiments, respectively. Besides, the presence of methanogens revealed that heat treatment and controlling moderately acidic pH (5.5) could not completely eliminate them and resulted in CH4 generation, rather than H2 production.

Anaerobic digestion is an effective technology to recover energy from oily food waste. A single-stage system and temperature-phased two-stage systems with and without recycle for anaerobic digestion of oily food waste were constructed to compare the operation performances. The synchronous operation indicated the similar ability to produce methane in the three systems, with a methane yield of 0.44 L/g VSadded. The pH drop to less than 4.0 in the first stage of two-stage system without recycle resulted in poor hydrolysis, and methane or hydrogen was not produced in this stage. Alkalinity supplement from the second stage of two-stage system with recycle improved pH in the first stage to 5.4. Consequently, 35.3% of the particulate COD in the influent was reduced in the first stage of two-stage system with recycle according to a COD mass balance, and hydrogen was produced with a percentage of 31.7%, accordingly. Similar solids and organic matter were removed in the single-stage system and two-stage system without recycle. More lipid degradation and the conversion of long-chain fatty acids were achieved in the single-stage system. Recycling was proved to be effective in promoting the conversion of unsaturated long-chain fatty acids into saturated fatty acids in the two-stage system.

During the transesterification of triglycerides with methanol catalyzed by immobilized lipase resin (Novozym 435 (N435)) in a glass vial, two types of aggregate of N435 particles were observed: a thin-layer aggregate on the glass surface inside the vial, and bulky aggregates. This prompted us to investigate the conditions under which only one type of aggregate could be formed, by changing the material from which the reaction vial was made and the feed ratio of N435 to the cross section of the reaction glass vial. When a polypropylene vial was used, only the bulky aggregates were formed, and reducing the feed ratio led to only the thin-layer aggregate being formed. We also examined the influence of morphological variation of the aggregates on the reaction yield. The thin-layer aggregate showed high activity, with a reaction yield of 0.932. In contrast, the bulky aggregate grew as the reaction time elapsed, resulting in a reduction in the surface area of the enzyme resin, consequently giving not only a reaction yield of about 0.454 but also low repeatability. These results show that the reactor material and feed ratio strongly affect the reaction yield as well as the aggregation form of enzyme resin. Finally, the durability of the thin-layer aggregate and the effect of accumulation of glycerin were investigated.

Anaerobic membrane bioreactor (AnMBR) holds great promise to treat a broad range of waste streams for concurrent pollutants transformation and biofuels harvest while producing less digestate residuals. In this review, recent research advances, new discoveries and commercial application status of AnMBR technique were summarized and reported. A comprehensive comparison analysis designed herein demonstrated its fascinating superiorities over the conventional activated sludge-based processes with regards to good permeate quality, less digestate residuals, low operational costs, net profit/energy output, and outstanding economic and environmental benefits. Despite the great progress achieved previously, there are still numerous challenges head for AnMBR platform applications to be tackled, particularly for severe membrane fouling, low methane content in biogas, highly dissolved methane, poor ammonia removal and phosphorus recovery, etc. To address the above problems, a new-generation process, i.e. so-called “Integrated Multistage Bio-Process (IMBP)” constituted of solar-driven bioelectrochemical system (BES)-AnMBR, partial nitritation/anammox (PN/A), nitrate reduction via anaerobic oxidation of methane (AOM) and biological/chemical phosphorus precipitation units, was proposed in this article, with versatile capabilities in simultaneous biowastes valorization, CO2 electromethanogenesis and simultaneous biogas upgrading, in-situ fouling control, ammonia removal, dissolved methane reutilization, and phosphorus recover as hydroxyapatite-rich nutrients. Despite the uncertainties about whether this approach possesses the powerful potential to dominate the future, but most surely, this hybrid concept will enhance the deployment and industrial competitiveness of AnMBR-based technologies in real-world scenarios, facilitating the establishment of the energy-sustainable and low-carbon society. Of course, more efforts are still required to demonstrate the feasibility of this integrated biorefinery approach. Nonetheless, this review opens up new research opportunities to integrate with other newly emerging processes to develop robust, multifunctional and sustainable AnMBR-based technologies towards biowaste biorefinery, chemical energy harvest and green, carbon-neutral society.

De-oiled grease trap waste (GTW) could be a feasible substrate for anaerobic digestion. However, due to high concentration of lipid, the long-chain fatty acid (LCFA), as an intermediate in the anaerobic lipid degradation, easily inhibits the anaerobic digestion, resulting in long recovery period. Four recovery strategies: bentonite addition, water dilution, mixing with low LCFA substrate and mixing with inocula, with control test as comparison, were employed in order to accelerate the recovery process of mesophilic anaerobic sludge. Adding bentonite, water dilution with 80% mixing ratio and mixing with active inocula achieved shortening of the recovery process. The whole recovery time took approximately 3.5 months for the control test, as calculated from the beginning to the end of the lag time after de-oiled GTW was re-added as F/I ratio of 0.4. At least 10 g l−1 of bentonite addition was necessary for the fast recovery of the inhibited sludge, with the whole recovery time one month shorter than the control test. 1.5 months could be saved for the whole recovery process when the strategy of water dilution with 80% mixing ratio was considered. The more inocula were mixed with the inhibited sludge, the more the recovery period was lessened. For the strategy of mixing with inocula with the mixing ratio 80%, only 20 days were needed for the whole recovery process.

article i nfo Article history: This study dealt with a new approach for the removal of 5-hydroxy methyl furfural (5-HMF) from dilute acid pretreatedredalgal hydrolysateusing hybrid immobilizedcells alongwith thegenerationofH2asenergy carrier. Under batch conditions, the peak 5-HMF removal of 1.6 g/L (100% removal) and hydrogen production rate of 1.48 L/L-d were obtained at 50% (v/v) algal hydrolysate content which is equivalent to 16.6 g sugar/L. Beyond the content, only the 5-HMF removal has been taken place, but the hydrogen production has been inhibited sig- nificantly. Further, an anaerobic sequencing batch operation performed using the optimal 50% AH concentration showed a stable hydrogen production rate and yield of 4.8 L/L-d and 2.40 mol/mol hexoseutilized respectively. © 2015 Elsevier B.V. All rights reserved.

The feasibility of anaerobic co-digestion of waste activated sludge (WAS) and grass Egeria densa ( E.d. ) with four different WAS: E.d. ratios was evaluated for the first time under mesophilic conditions. First-order kinetic, modified Gompertz, and Cone models were employed to reveal the principle kinetics of methane-rich bioenergy production from co-digestion. The results showed that the addition of E.d. could greatly upgrade the sludge methane production, and the highest methane yield averaged 198.32 ± 2.61 mL/g VS added for WAS: E.d. ratio of 0.7: 0.3, 18.72 ± 0.14% higher respective to that of WAS alone (about 176.36 mL/g VS added ). E.d. improved the solubilization of co-substrates and avoided the build-up of volatile fatty acids (VFAs) and free ammonia ([NH 3 ]) and subsequent inhibition, inducing a stable digestion environment. Model simulation indicated Cone model best fitted the actual evolution of methane production, as evidenced by low Root Mean Square Prediction Error (rMSPE) and Akaike’s Information Criterion (AIC), as well as high Pearson’s correlation between the predicated and actual values. Additionally, the parameters analysis highlighted that the co-digestion with E.d . substantially promoted the hydrolysis rate ( k hyd ) and methanogenesis potential ( f d ) of sludge, further explaining the increased solids removal and output of methane. This study demonstrated the sustainability and attractiveness of anaerobic co-digestion of sludge and grass E.d. , providing a sound basis for cost-efficient biomass stabilization and bioenergy recovery.

The characteristics of hydrogen fermentation in a membrane bioreactor (HF-MBR) fed with food waste were investigated at thermophilic condition. The HF-MBR was operated at three different organic loading rates (OLRs) of 70.2, 89.4 and 125.4 kg-COD/m3/day. Biogas production rate increased from 22.4 to 32.8 and 62.5 l/day with OLR. The maximum Hydrogen yield and production rate were 111.1 mL-H2/g-VS added and 10.7 l-H2/L/day at an OLR of 125.4 kg-COD/m3/day. The total carbohydrate degradation was better than 96% throughout the experimental runs. Continuous H2 production from food waste with CH4-free biogas was successfully sustained in the HF-MBR for 90 days. The microbial community was dominated by Clostridium sp. strain Z6. The H2 production was significantly improved by shortening the retention time and increasing the OLRs. The HF-MBR showed an H2 production capacity at the high OLRs due to its higher cell retention.

Municipal solid wastes (MSW) collected in Kyoto city were carefully separated, and the waste-type proportion in MSW was surveyed. A hydrogen/methane fermentation batch experiment was conducted under thermophilic condition using twenty different types of MSW components. Biodegradable wastes in the MSW almost consist of vegetable kitchen waste, and the characteristics of hydrogen and methane fermentation of MSW were similar to that of vegetable kitchen waste. Hydrogen production per g VS added was considerably positively correlated with easily degradable carbohydrates concentration and negatively correlated with cellulosic materials concentration. The various feedstocks could be classified into four groups according to nutrient composition (protein, fat, cellulosic materials and easily degradable carbohydrates), and the feedstocks belonging to carbohydrates rich group showed higher hydrogen yields than the other feedstocks. Rough hydrogen yield could be easily predicted by concentration of easily degradable carbohydrates.

The two-stage hydrogen–methane fermentation process with different patterns of recirculation was investigated. Operations with the circulation of heat-treated sludge performed considerably better than those with the recirculation of raw sludge with respect to both the hydrogen production rate and yield. In addition, the results of the batch tests demonstrated that circulated sludge was capable of consuming hydrogen under acidogenic pH while the heat-treated sludge was not. These results suggest that the recirculation of active methanogenic sludge had an inhibitive effect on the hydrogen production, which can likely be attributed to the high hydrogen-consuming activity of microorganisms present in the circulated sludge. On the other hand, operations without any sludge recirculation did not perform well in terms of hydrogen production or carbohydrates degradation compared to those with recirculation, perhaps due to a shortage of available nitrogen. This suggests that sludge recirculation in effect supplemented the NH 4 + in the hydrogen reactor.

In order to localize the generator site of epileptiform discharges, we applied the techniques of jerk-locked back averaging (JBA) of magnetoencephalographic (MEG) activities and dipole source localization in a patient with epilepsia partialis continua (EPC), who showed continuous, focal myoclonic jerks in the right arm. The myoclonic discharges in the right muscle were used as a trigger pulse. JBA revealed consistent EEG and MEG transients that coincided consistently and constantly preceded the myoclonic jerks. The estimated dipoles of MEG were localized in a restricted area in the left precentral area, which closely correlated with the area of epileptic discharges recorded in electrocorticography. Therefore, JBA of MEG is considered to be a useful non-invasive method for localizing the epileptogenic area in EPC.

Intercellular adhesion molecule 1 (ICAM 1) is an inducible protein ligand which is up-regulated during inflammation and is either not constitutively expressed or is only expressed at low levels. The expression of ICAM 1 increases in HTLV-I infected T cell lines as well as in CD4+ T-cells of peripheral blood lymphocytes (PBLs) from HAM/TSP patients. After PBLs of HAM/TSP patients were cultured in the presence of stimulating anti-ICAM 1 antibody, the expression of the HTLV-I gag protein in PBLs was observed by both immuno-histostaining and western blot analysis using HTLV-I Ag-specific mouse monoclonal antibody. These data thus suggested that the signal transduction via adhesion molecule, ICAM 1 could induce the transcription of the HTLV-I gene and this might therefore play an important role in the pathogenesis of HAM/TSP.

Duchenne muscular dystrophy (DMD) is a degenerative disorder of the skeletal muscle in human and is caused by mutations in the dystrophin gene. The mdx mouse is a spontaneous mutant and an animal model for DMD. It has a point mutation in exon 23 of the dystrophin gene that eliminates the expression of dystrophin. However, this mutation does not disrupt the expression of four other shorter isoforms that are also expressed from the dystrophin gene through differential promoter usage. We generated another mutant mouse by gene targeting. Exon 52 of the dystrophin gene was disrupted, because the deletion of this exon is known to result in the DMD phenotype in human. In this mouse (mdx52), Dp140 and Dp260, shorter dystrophin isoforms, were absent in addition to dystrophin. The skeletal muscles were hypertrophic and the histology exhibited variations in the fiber size with a necrotic and regenerating process. This mouse is thus considered to represent another model for DMD.

In the present study we examined the laminar distributions of four types of chemically defined subpopulations of non-principal neurons, that is, those immunoreactive for parvalbumin (PV), calretinin (CR), nitric oxide synthase (NOS) and somatostatin (SS), in the rat hippocampus, by estimating their approximate numerical densities (NDs) and percentages in specific layers according to the 'disector' principle. CR-immunoreactive (CR-IR) neurons and NOS-IR neurons were scattered throughout layers, but among layers in each subdivision their NDs were largest in the principal cell layers, where 30-45% of CR-IR and NOS-IR somata in each subdivision were located. In addition, CR-IR and NOS-IR somata were also concentrated at the border between the stratum radiatum (SR) and stratum lacunosum moleculare (SLM) in the CA1 region, where the NDs of these neurons were far larger than those in the SR/SLM as a whole and close to those in the stratum pyramidale (SP) (CR-IR somata at the ventral level and NOS-IR somata at the dorsal level) or larger (NOS-IR neurons at the ventral level). The NDs of CR-IR somata were dorsoventrally different in all layers of the CA3 region, the SR/SLM in the CA1 region and the hilus and the granule cell layer (GCL) of the dentate gyrus (DG), whereas the NDs of NOS-IR somata were dorsoventrally different in all layers of the CA3 region and the SP in the CA1 region. In contrast, approx. 90% of somatostatin-like immunoreactive (SS-LIR) neurons were located in the stratum oriens/alveus (SO/SA) in the CA1 region and in the hilus of the DG, where they were the most predominant cell type among the four types of non-principal cells. In contrast, in the CA3 region, SS-LIR somata were scattered in various layers. The majority (50-70%) of PV-IR neurons were located in the principal cell layers, whereas one-fourth to one-third of them were located in the SO/SA and hilus. The NDs in the SP of the CA1 and CA3 regions showed a significant dorsoventral difference. Although PV-IR somata were most numerous among the four non-principal cell groups in the SP of the dorsal CA1 region, they were not necessarily predominant in the principal layers in other regions, that is, in the ventral CA1 region, CA3 region and DG, where the NDs of CR-IR and/or NOS-IR somata were nearly equal to or larger than that of PV-IR somata. The present study not only reveals the laminar distribution patterns of four types of non-principal neurons in each subdivision quantitatively, but also illustrates the prominent differences in the compositions of four types of non-principal cells in each layer of each subdivision.

We report on the case of a 70-year-old man with primary macroglobulinemia who showed cranial polyneuropathy and extensive radiculoneuropathy. His serum contained an IgM lambda monoclonal antibody which reacted with both a high molecular weight protein in grey matter and purified myelin basic protein (MBP) on immunoblotting. In an immunohistochemical study, strong immunoreactivity was detected only in the cytoplasm of neurons and weak immunoreactivity was detected in myelin. These findings suggest that this antibody may be related to the pathogenesis of neuronal damage in patients with macroglobulinemia.

We have generated a line of mice deficient in adrenoleukodystrophy protein (ALDP) by gene targeting in order to clarify the pathophysiology of adrenoleukodystrophy (ALD). ALDP-deficient male and female mice appeared normal clinically at least up to 12 months. Western blot analysis showed the absence of ALDP in the brain, spinal cord, lung, and kidney and normal expression of PMP70 in the liver, lung, and kidney. The amounts of C26:0 increased by 73–240% in the brain, spinal cord, lung, and kidney. β-Oxidation of very long chain fatty acids (VLCFA) in cultured hepatocytes and fibroblasts was reduced to 35–50% of normal. Light and electron microscopy did not show demyelination in the brain, spinal cord, and peripheral nerve. Thus, the deficiency of ALDP in mice impairs the peroxisomal fatty acid β-oxidation but does not duplicate the clinical and pathological abnormalities of the human ALD. These observations suggest that the accumulation of VLCFA alone is not sufficient to cause demyelination in the nervous system.

We studied the distribution of activated microglia in the brain during kainic acid-induced acute hippocampal seizures in rats. Although no microglial activation was observed 4 h after seizure induction, activation was detected in the primary focus and also in other selected structures in the limbic and non-limbic structures after 8 and 24 h, in the absence of any obvious morphological changes in the neurons. The structures with activated microglia were highly consistent with those included in the propagation pathways of the hippocampal seizures. These findings thus suggest that the microglial cells are activated through the propagation pathways by the seizure activities that propagate transynaptically from the primary focus, even without any apparent neuronal injury.

A molecular analysis of 4 Japanese adrenoleukodystrophy (ALD) patients was carried out, according to the recently published report on ALD gene cDNA. In a Southern blot analysis, we were not able to detect a large deletion in all patients. In a Northern blot analysis, no mRNA was detected in one patient, while the others had normal mRNA in both size and amount. Three patients had missense mutations including; 534 Pro → Leu ( 1987 C → T), 660 Arg → Trp ( 2364 C → T), and 512 Gly → Ser ( 1920 G → A), respectively. These mutations existed in the C-terminal region conserved in the ATP-binding cassette superfamily of transporters. In a Western blot analysis using polyclonal antibodies against the C-terminal peptide as well as the whole peptide of ALD protein, no 80 kDa protein was found in any of the 4 patients, which was observed in the control cells. The ALD protein in 3 patients with a missense mutation might be degraded immediately after translation because of the unstable higher structure or by the disruption of the hitherto unknown targetting signal to the peroxisome. The molecular analysis of the ALD gene as done in this study is thus considered to be the first step to further elucidate the pathogenic mechanism of ALD.

We showed the analysis of the androgen receptor gene in 6 patients with bulbospinal muscular atrophy (BSMA). Four of them had typical manifestations of Kennedy's disease, while the other 2 patients did not show androgen insensitive signs such as gynecomastia or testicular atrophy. Enlarged CAG repeats were found in 4 patients with typical Kennedy's disease and 1 patient without androgen insensitive signs. This fact suggests that the DNA diagnosis by analysis of the androgen receptor gene is very useful to distinguish Kennedy's disease from other forms of BSMA.

Recently, we purified a Ca2+-binding protein from rat spermatogenic cells [Biochem. Biophys. Res. Commun. 176, 1358-1364, 1991]. In the present study, this protein was identified as calreticulin, which is a resident protein of the endoplasmic reticulum (ER). Immunohistochemical studies revealed that calreticulin was present in the acrosome of both round spermatids and mature sperm. However, under immunoelectron microscopy, gold-particles were seen over other subcellular structures of spermatocytes, spermatids, and Sertoli cells. When the labeling density in subcellular structures of spermatids was analyzed, the acrosome was found to be most heavily labeled and the Golgi apparatus was second. The complete amino acid sequence of calreticulin, deduced from the cDNA sequence, shares a high degree of identity with that of the analogous mouse protein. The cDNA encoded a protein of 416 amino acids, including a 17-residue NH2-terminal signal sequence. The mature protein contains a KDEL sequence as an ER signal at the COOH terminus. Sperm calreticulin contained no glycosyl moiety. Northern blot analysis of RNAs from purified populations of rat spermatogenic cells indicated that the calreticulin mRNA was present in both pre- and postmeiotic cells. Immunoblot analysis of calreticulin during developmental stages showed that calreticulin was detected in the testis between the ages of 5 and 50 days. Furthermore, purified rat calreticulin contained two Ca2+-binding sites, a low affinity/high capacity site and a high affinity/low capacity site. These results suggest that calreticulin, which is not specific to testis, is closely associated with spermatogenesis of rats. This ER protein may be incorporated into the acrosomal vesicle via the Golgi apparatus, without glycosylation, during spermiogenesis, and may play an important role in the regulation of cell functions such as sperm motility and acrosome reaction.

We report a 38-year-old male with recurrent cerebral infarction, who had a history of juvenile rheumatoid arthritis and suffered from ischemic necrosis of the jejunum at the age of 34 years. When the patient showed gastrointestinal symptoms, amyloid deposits were found with colon biopsy. The patient experienced recurrent episodes of headache and left homonymous lower quadrantanopsia at the age of 38 years. CT and MRI of the head revealed cerebral infarction in the right parieto-occipital region. At this time, amyloid deposits were detected in the mucosa of the stomach, duodenum, and rectum. Immunostaining revealed that amyloid fibrils were composed of amyloid A (AA) protein. It is possible that AA type amyloidosis may be of importance in the etiology of cerebral infarction in the young adult.