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Ten species of white-rot fungi were evaluated for their ability to decolorization of palm oil mill effluent. The highest decolorization efficiency was found with Trametes elegans (PP17-06), followed by Ganoderma sp.2 (PW17-06) and Ganoderma sp.2 (PW17-177), respectively. T. elegans was further evaluated for the long-term performance of decolorization for 24 d. The optimal retention time for the decolorization was 8 d, with a color removal efficiency of 47.7%. Beyond 18 d of incubation, decolorization efficiency was reduced due to the autolysis of enzymes. During the biodegradation process, manganese peroxidase enzyme activities reached a maximum of 36.03 U.L-1. However, no significant laccase and lignin peroxidase activities were observed. T. elegans was also assessed for decolorization performance through biosorption on mycelial biomass. The synthesis of the enzyme was prevented by exposing the mycelium to HgCl2. Within an optimal contact time of 2 d, decolorization efficiency reached 12.5% with ADMI reduction from 4259.0 (±20.1) ADMI to 3727 (±104.04) ADMI. Results indicate that the adsorption capacity was reached at this time, and no significant color removal can be achieved by biomass. Results obtained in this study showed the potential of T. elegans in decolorizing palm oil mill effluent. [ABSTRACT FROM AUTHOR]

Methane (CH 4) production from palm oil mill effluent (POME) pre-treated by ozonation was conducted under mesophilic (37 °C) condition. The results demonstrated that methane can be produced from both non-ozonated and ozonated POME at a concentration range of 3,000 to 15,000 mg COD L−1. Methane yield rised 54% when POME was pre-treated by ozonation at POME concentration of 15,000 mg COD L−1. The methane yield increased the POME concentration was increased. At POME above 15,000 mg COD L−1, the methane yield was dropped dramatically. The methane production rates (R max) and yields exerted similar trend regarding the POME concentration. Accumulation of volatile fatty acids in the reactor posed the drop of methane production. Ozonation pretreatment process of POME can improve the biodegradability of the complex organic matter in POME and enhanced methane yield and rate at POME concentration range of 3,000–15,000 mg COD L−1. • Mesophilic fermentation setup for methane production from POME. • Ozonation pre-treatment raised POME biodegradability. • Ozonation pre-treated POME raised yield 54%. [ABSTRACT FROM AUTHOR]

Abstract Enhancement of biological H 2 production efficiency with pre-ozonation process of palm oil mill effluent (POME) prior to thermophilic dark fermentation (55 °C) was investigated. H 2 fermentation experiments were conducted using varying concentrations of raw and ozonated POME. Results revealed that H 2 can be produced from both raw and ozonated POME under thermophilic fermentation. Maximum H 2 production yield of 77 mL.g−1COD removed was obtained from ozonated POME, which was higher than that of 51 mL·g−1 COD removed obtained from raw POME at the highest concentration of 35,000 mg COD.L−1. Meanwhile, the specific H 2 production rate (R' max) of 1.9 and 1.5 mL·h−1·g−1 TVS were observed in raw and ozonated POME at the concentration of 25,000 mg COD.L−1, respectively. The main metabolic products during POME fermentation were acetic and butyric acids and trace amount of valeric acid. Propionic acid and ethanol have contributed, which could be reduced H 2 production in all batch experiments for both POME. The highest efficiency of total and soluble COD removal of 24 and 25% was obtained from the raw POME, and those of 19 and 25% was obtained from the ozonated POME. The present study demonstrates that the POME loading was greatly influenced on the H 2 production yields and rates. The comparative results showed that the ozonated POME gave higher H 2 yields than the raw POME. Thus, demonstrating that the ozonation process significantly improved the POME biodegradability, which is able to enhance H 2 production yields. However, the ozone pre-treatment was not improved in the specific H 2 production rates. Highlights • Thermophilic biohydrogen production using mesophilic mixed culture as inoculum. • Maximum biohydrogen yield obtained at POME concentration of 25,000 mg COD L-1. • Pretreatment of POME using ozone improved the biohydrogen yield. [ABSTRACT FROM AUTHOR]

Abstract Generation of electricity and treatment of the distillery wastewater (DW) were achieved in air-cathode single-chamber MFCs (SCMFCs). The maximum current density of 2.36 mA · m−2 and power density of 39.21 mW·m−3 were obtained at DW concentration of 2000 mg COD.L−1. The trends of current and power density were decreased with increasing concentration from 2000 to 4000 mg COD.L−1. The maximum soluble COD removal was 62.2% (CE = 8.77%, 1500 mg COD.L−1). The electrochemical activity of the microbes in the SCMFCs showed significantly high oxidized substrate in the semi-batch distillery wastewater operation. The microbial communities on the anode biofilms fed with a high concentration of distillery wastewater (4000 mg COD.L−1) operation were analyzed based on 454 pyrosequencing of the 16S rRNA gene revealed different microbial communities. The dominant phylum were Proteobacteria (28.5%), Bacteroidetes (23.4%) and Chlorobi (22.8%), while Firmicutes (9.3%) were detected as a lesser proportion of the total community. The microbial community structures suggested that Proteobacteria might be important for the production of power density in distillery wastewater fed air-cathode SCMFC. These results demonstrate that the SCMFCs can simultaneously generate electricity and achieve wastewater treatment from a renewable source. Highlight • SCMFCs can simultaneously generate electricity and reduce pollution in distillery wastewater. • Current density of 2.36 mA.m−2 and power density of 39.21 mW.m−3 were achieved. • Proteobacteria is the main dominant bacterial phylum in SCMFCs. [ABSTRACT FROM AUTHOR]

Abstract Biomethane (CH 4) was recovered from co-digestion process of waste glycerol and banana wastes. The wastes used contain waste glycerol with varying concentrations from 7.5 to 90 g L−1 and banana peel in the range 2.5–10 %w·v−1. The co-substrate mixture ratio was implemented in 0.5 L batch reactor operated at 37 °C and pH 7 for 120 h. The composition of biogas gas and liquid samples (COD, VFA, pH, alkalinity) were analyzed every 12 and 24 h, respectively. The optimum condition to produce CH 4 was found at 7.5 g L−1 waste glycerol mixed with 7.5% banana peel. The highest CH 4 yield and CH 4 production potential were 0.281 m3 kg−1 COD and 652 mL, respectively. Highlights • CH 4 recovery from co-fermentation of biodiesel waste and banana waste. • The optimum co-fermentation yielded 0.281 m3· CH 4 kg−1 COD. • Co-fermentation of glycerol waste and banana waste yielded maximum CH 4 production. [ABSTRACT FROM AUTHOR]

Bioethanol is a clean and renewable biofuel, which can be produced from low cost and renewable feedstocks via fermentation process. The microbes present in an upflow anaerobic sludge blanket (UASB) reactor for wastewater treatment were tested for application in batch fermentation of ethanol at varying glycerol concentrations, and pHs of culture medium. Ethanol was the main fermentative product in this work. Ethanol concentration between 3.9 and 11.1 g L −1 ; and ethanol yields between 0.66 and 0.81 mol ethanol mol −1 glycerol were obtained. The ethanol concentration and yield were highly dependent on the initial glycerol concentration. The highest ethanol concentration of 11.1 g L −1 was obtained after 72 h of fermentation at the initial glycerol concentration of 45 g L −1 . Ethanol production and glycerol utilization were highly correlated. Denaturing gradient gel electrophoresis (DGGE) pattern revealed there were microbial selection and adaption during the fermentation. 16S rRNA gene sequences showed that the seed culture comprised largely of uncultured bacteria with various Proteobacteria , Bacteroidetes , and Firmicutes . Enrichment of Proteobacteria , particularly Enterobacter and Klebsiella bacteria occurred within 24 h of the fermentation and the ethanol producing microcosm at 72 h was dominated >95% by these 2 strains. The major ethanol producers were identified as Enterobacter and Klebsiella strains. This work demonstrated the potential use of biodiesel derived glycerol as a feedstock for the ethanol production, and revealed the major roles of Enterobacter and Klebsiella in the ethanol production from glycerol. [ABSTRACT FROM AUTHOR]

Hydrogen sulfide (H 2 S), a highly corrosive gas, is found in biogas due to the biodegradation of proteins and other sulfur containing organic compounds present in feed stock during anaerobic digestion. The presence of H 2 S is one of the biggest factors limiting the use of biogas. It should be removed prior to application of biogas in an electric generator or industrial boiler. The present research evaluated the performance of biotrickling filter inoculated with Halothiobacillus neapolitanus NTV01 (HTN) on the H 2 S removal from synthetic biogas. HTN, isolated and purified from activated sludge, is a sulfur oxidizing bacteria able to degrade H 2 S and thiosulfate to elemental sulfur and sulfate, respectively. Operational parameters in a short term operation were varied as following; gas flow rate (0.5–0.75 LPM); EBRT (40–120 s); the inlet H 2 S concentrations (0–1500 ppmv); liquid recirculation rate (3.6–4.8 L/h). EBRT showed a greater effect to the removal efficiency than increasing H 2 S concentration. Longer EBRT resulted higher removal efficiency. The changes of liquid recirculation rates did not significantly affect the removal efficiency. In long term operation, the gas flow rate and liquid recirculation rate were fixed at 0.5 LPM (120 s EBRT) and 3.6 L/h; and H 2 S concentrations were varied (0–2040 ppmv). The maximum elimination capacity was found as 78.57 g H 2 S/m 3 h, which had greater performance than the previous studies. [ABSTRACT FROM AUTHOR]