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The discharge of leachate poses a serious risk to both surface water and groundwater from landfills. As rainwater and moisture seep through waste in landfills, it will release leachate which is high in concentration of organic matter and ammonium nitrogen. Adsorption process using activated carbon was used as one of the tertiary treatment processes in the landfill. This paper presents the utilization of biomass-based adsorbents to substitute the current activated carbon in the landfills. The carbonization process was employed using a 3-tonne self-sustained pool-type reactor, to produce micropores biochar as bio-adsorbent. The carbonization proceeds for 48 h using feedstocks with different initial moisture content of 20% and 40%. The biochar produced had microporosity ranging from 1.8 to 15.4 nm and a surface area of 192.9–231 m2/g. The use of biochar for landfill leachate treatment has shown satisfactory results, with COD, ammoniacal nitrogen, and total Kjeldahl nitrogen removal at 73%, 70%, and 97%, respectively, and heavy metals content value below the Malaysian discharge limits. This exemplifies the potential of biochar as a bio-adsorbent for treating landfill leachate and the feasibility of up-scaling biochar production from wood waste.

In order to meet the growing demand for adsorbents to treat wastewater effectively, there has been increased interest in using sustainable biomass feedstocks. In this present study, the dermal tissue of oil palm frond was pyrolyzed with superheated steam at 500 °C to produce nanoporous biochar as bioadsorbent. The effect of operating conditions was investigated to understand the adsorption mechanism and to enhance the adsorption of phenol and tannic acid. The biochar had a microporous structure with a Brunauer-Emmett-Teller surface area of 422 m2/g containing low polar groups. The adsorption capacity of 62.89 mg/g for phenol and 67.41 mg/g for tannic acid were obtained using 3 g/L biochar dosage after 8 h of treatment at solution pH of 6.5 and temperature of 45 °C. The Freundlich model had the best fit to the isotherm data of phenol (R2 of 0.9863), while the Langmuir model best elucidated the isotherm data of tannic acid (R2 of 0.9632). These indicated that the biochar-phenol interface was associated with a heterogeneous multilayer sorption mechanism, while the biochar-tannic acid interface had a nonspecific monolayer sorption mechanism. The residual concentration of 26.3 mg/L phenol and 23.1 mg/L tannic acid was achieved when treated from 260 mg/L three times consecutively with 1 g/L biochar dosage, compared to a reduction to 72.3 mg/L phenol and 69.9 mg/L tannic acid using 3 g/L biochar dosage in a single treatment. The biochar exhibited effective adsorption of phenol and tannic acid, making it possible to treat effluents that contain varieties of phenolic compounds.

The influence of biomass cellulosic content on biochar nanopore structure and adsorption capacity in aqueous phase was scarcely reported. Commercial cellulose (100% cellulose), oil palm frond (39.5% cellulose), and palm kernel shell (20.5% cellulose) were pyrolyzed AT 630 °C, characterized and tested for the adsorption of iodine and organic contaminants. The external surface area and average pore size increased with cellulosic content, where commercial cellulose formed biochar with external surface area of 95.4 m2/g and average pore size of 4.1 nm. The biochar from commercial cellulose had the largest adsorption capacities: 371.40 mg/g for iodine, 86.7 mg/L for tannic acid, 17.89 mg/g for COD and 60.35 mg/g for colour, while biochar from palm kernel shell had the least adsorption capacities. The cellulosic content reflected the differences in biochar nanopore structure and adsorption capacities, signifying the suitability of highly cellulosic biomass for producing biochar to effectively treat wastewater.

Most palm oil mills adopted conventional ponding system, including anaerobic, aerobic, facultative and algae ponds, for the treatment of palm oil mill effluent (POME). Only a few mills installed a bio-polishing plant to treat POME further before its final discharge. The present study aims to determine the quality and toxicity levels of POME final discharge from three different mills by using conventional chemical analyses and fish (Danio rerio) embryo toxicity (FET) test. The effluent derived from mill A which installed with a bio-polishing plant had lower values of BOD, COD and TSS at 45 mg/L, 104 mg/L, and 27 mg/L, respectively. Only mill A nearly met the industrial effluent discharge standard for BOD. In FET test, effluent from mill A recorded low lethality and most of the embryos were malformed after hatching (half-maximal effective concentration (EC50) = 20%). The highest toxicity was observed from the effluent of mill B and all embryos were coagulated after 24 h in samples greater than 75% of effluent (38% of half-maximal lethal concentration (LC50) at 96 h). The embryos in the effluent from mill C recorded high mortality after hatching, and the survivors were malformed after 96 h exposure (LC50 = 26%). Elemental analysis of POME final discharge samples showed Cu, Zn, and Fe concentrations were in the range of 0.10–0.32 mg/L, 0.01–0.99 mg/L, and 0.94–4.54 mg/L, respectively and all values were below the effluent permissible discharge limits. However, the present study found these metals inhibited D. rerio embryonic development at 0.12 mg/L of Cu, and 4.9 mg/L of Fe for 96 h-EC50. The present study found that bio-polishing plant installed in mill A effectively removing pollutants especially BOD and the FET test was a useful method to monitor quality and toxicity of the POME final discharge samples.

Microorganisms are progressively adopted as reliable and specific bioindicators of pollution, with Alcaligenaceae and Chromatiaceae being recently proposed to indicate contamination in river water due to palm oil mill effluent (POME) final discharge. This study was conducted to evaluate the reliability of these bacteria to act as specific bioindicators by assessing their detections in correlation with environmental factors in rivers polluted by POME final discharge when compared to by other pollution sources. By using the Illumina MiSeq high throughput sequencing platform, bacterial diversities and compositions were compared among unpolluted (upstream) river, polluted rivers due to POME final discharge and other rivers polluted by mining, chemical and automotive industries. To correlate between bacterial compositions and metabolisms in rivers subjected to different pollutants sources, the viability and the ratio of the high and low nucleic acids (HNA/LNA) bacterial cells were also compared by using a double staining assay based on flow cytometry. Interestingly, Alcaligenaceae and Chromatiaceae were found only in POME final discharge polluted rivers (>0.15%) but were not detected in rivers polluted by other pollutants. Higher bacterial cell viability was detected in rivers polluted by POME final discharge (86–91%) as compared to the other polluted rivers (15–80%). From the viable fractions of the bacterial cells, higher HNA cells (91–93%) were quantified in the POME final discharge receiving rivers but with only 5–18% in the other rivers. These trends indicated that the nutrients carried by the POME final discharge enhanced the growth of bacteria in the receiving river water that might include Alcaligenaceae and Chromatiaceae. These results suggested that either Alcaligenaceae or Chromatiaceae or both were unique in the POME final discharge polluted rivers but not in the others. They could function as specific and reliable bacterial bioindicators relevant for the est

Advances in biochar production and modification have extended the applications of biochar to wastewater treatment. However, not all feedstocks produced porous biochar at a moderate temperature suitable for wastewater treatment. In this study, biochar was produced from oil palm frond using steam pyrolysis at 500 °C and pulverized to granular and micro-fine particles. Both biochar particles were characterized and applied as adsorbents for treating final discharge of palm oil mill effluent. The effluent was also filtered and treated to examine the effect of suspended solids on adsorption capacity. The biochar had Brunauer-Emmett-Teller surface area of 406.6 m2 g−1. Pulverization eliminated the residual macropores in granular biochar, created new external surface area, and exposed constricted nanopores, which resulted in increasing the surface area to 457.7 m2 g−1. The adsorption capacity decreased from 24.6 to 6.1 mg g−1 for chemical oxygen demand and 49.0 to 10.9 Pt–Co g−1 for color by increasing the dosage of micro-fine biochar from 5 to 30 g L−1. The total suspended solids affected the adsorption capacity of granular biochar by blocking residual macropores that provide access to adsorption sites in micropores and mesopores. At 30 g L−1, the micro-fine biochar exhibited an effective reduction of chemical oxygen demand from 224 to 41.6 mg g−1 and color from 344 to 15 Pt–Co g−1 making the wastewater suitable for reuse in palm oil mills and safe for discharge into the aquatic environment.

Conventional aerobic treatment of facultatively treated palm oil mill effluent (POME) containing phenolic compounds such as phenol, encounters difficulty because of microbial inhibition. In this study, adsorption of phenol in facultatively treated POME was proposed as a solution for mitigating the inhibition. Low-cost biochars produced from oil palm frond using nitrogen or steam pyrolysis at 600 °C were characterized and investigated for efficient and effective removal of phenol. Nitrogen and steam pyrolysis yielded mesoporous biochars with Brunauer–Emmett–Teller surface area of 368.4 m2/g and 461.3 m2/g respectively. Within 8 h, steam-derived biochar attained equilibrium capacity of 59.6 mg/L in distilled water, which decreased to 18.5 mg/L in facultatively treated POME. Steam-derived biochar exhibited slightly higher adsorption capacity for phenol in facultatively treated POME due to higher surface area, wider nanopore size distribution, a larger volume of mesopores and a stronger affinity for phenol. More than 90% of phenol was removed using 16–20 g/L dosage, yielding a facultatively treated POME with 0% inhibition to aerobic microbial growth. Overall, low-cost biochar produced from oil palm frond can be used as an efficient and effective adsorbent for adsorbing phenol in facultatively treated POME to enhance the performance of aerobic treatment system.

This study aims to elucidate the mechanism of carbon partitioning towards starch and triacylglycerol (TAG) under nitrogen stress. Whole-transcriptome analysis was performed using RNA sequencing before being validated with qRT-PCR. The strain, Chlorella vulgaris UPSI-JRM01, exhibited a two-stage response to nitrogen stress: i) carbohydrate accumulation, plastid protein degradation and amino acid biosynthesis; and ii) lipid accumulation, carbohydrate degradation and DNA damage. In the first stage, the genes responsible for plastid protein degradation (CD4A), amino acid biosynthesis (arg, GLSN, AHCY, win1), carbon fixation (RuBisCO, GapC, fba, TK) and starch synthesis (SS, SBE2) were upregulated. In the second stage, the upregulation of genes responsible for starch degradation (SP), glycolysis (PFO, PK, ACS), fatty acid biosynthesis (FabH, accD) and TAG accumulation (DGAT2) were observed. By contrast, the components of photosystem I (PsbD, PsbC, PsbB), photosystem II (PsaA), cytochrome b6/f (PetA, PetG) and F-type ATPase (beta, alpha) were downregulated. The results suggested that nitrogen stress triggered high starch accumulation before the carbon was partitioned towards triacylglycerol (TAG) for long-term energy storage by two different pathways: chloroplastic TAG synthesis and glycerolipid metabolism. The starch build-up functions served as a rapid response to nitrogen stress, whereas subsequent lipid accumulation benefited the long-term storage of energy. This research provides in-depth understanding of the metabolic changes triggered by nitrogen stress.

Background: Alzheimer’s disease (AD) is a neurodegenerative disorder and the commonest cause of dementia among the aged people. D-galactose (D-gal) is a senescence agent, while aluminium is a known neurotoxin linked to pathogenesis of AD. The combined administration of rats with d-gal and aluminium chloride (AlCl3) is considered to be an easy and a cheap method to obtain an animal model of AD. The plant Centella asiatica (CA) is reported to exert neuroprotective effects both in vitro and in vivo. Therefore, this study explored the protective effects of CA on cognition and brain ultrastructure in d-gal and AlCl3 induced rats. Materials and methods: Rats were exposed to d-gal 60 mg/kg/b.wt/day + AlCl3 200 mg/kg/b.wt/day and CA (200, 400 and 800 mg/kg/b.wt/day) and 1 mg/kg/b.wt/day of donepezil for 70 days. Different cognitive paradigms viz. T maze spontaneous alternation, modified elevated plus maze and novel object recognition test, were used to evaluate full lesions of the hippocampus, spatial learning and memory and non-spatial learning and memory respectively. Nissl’s staining was used to determine the survival of hippocampus CA1 pyramidal cells, while transmission electron microscopy was used to check the ultrastructural changes. Results: The results revealed that d-gal and AlCl3 could significantly impair behavior and cognitive functions, besides causing damage to the hippocampal CA1 pyramidal neurons in rats. In addition, it also caused ultrastructural morphological alterations in rat hippocampus. Conversely, co-administration o;f CA, irrespective of the dosage used, alleviated the cognitive impairments and pathological changes in the rats comparable to donepezil. Conclusion: In conclusion the results suggest that CA could protect cognitive impairments and morphological alterations caused by d-gal and AlCl3 toxicity in rats. Biochemical and molecular studies are ongoing to elucidate the probable pharmacodynamics of CA.

Research to understand human responses to wildlife and wildlife issues has predominantly focused on cognitions. Yet, as emotions are basic human responses to wildlife, emotions are important too. Integrating cognition and emotion concepts could foster the overall understanding of human-wildlife relationships. This study tested the relationships between valence (the pleasant-unpleasant dimension of emotion) regarding wildlife and wildlife value orientations (patterns of basic cognitions in the context of wildlife). Also, this study estimated the additional predictive potential of emotion next to cognition for the acceptability of lethal control and support for wildlife conservation. Analyses showed that valence was associated with wildlife value orientations. Valence had additional explanatory value next to cognition for conservation support. Valence, however, did not have additional predictive potential for acceptability of lethal control. Based on these findings, we recommend integrating cognition and emotion measurements in future research to understand human responses to wildlife issues. Also, wildlife managers could take the emotion of stakeholders into account in their communication and decision-making processes.

Cognitive impairments and cholinergic dysfunctions have been well reported in old age disorders including Alzheimer’s disease (AD). d-galactose (D-gal) has been reported as a senescence agent while aluminium act as a neurotoxic metal, but little is known about their combined effects at different doses. The aim of this study was to establish an animal model with cognitive impairments by comparing the effects of different doses of co-administrated D-gal and aluminium chloride (AlCl3). In this study male albino wistar rats were administered with D-gal 60 mg/kg.bwt intra peritoneally (I.P) injected and AlCl3 (100, 200, or 300 mg/kg.bwt.) was orally administered once daily for 10 consecutive weeks. Performance of the rats were evaluated through behavioural assessments; Morris water maze (MWM) and open field tests (OFT); histopathological examination was performed on the hippocampus; moreover biochemical measurements of acetylcholinesterase (AChE) and hyperphosphorylated tau protein (p-tau) were examined. The results of this experiment on rats treated with D-gal 60 + AlCl3 200 mg/kg.bwt showed near ideal cognitive impairments. The rats exhibited an obvious memory and learning deficits, marked neuronal loss in hippocampus, showed increase in AChE activities and high expression of p-tau within the tissues of the brain. This study concludes that D-gal 60 + AlCl3 200 mg/kg.bwt as the ideal dose for mimicking AD like cognitive impairments in albino wistar rats. It is also crucial to understand the pathogenesis of this neurodegenerative disease and for drug discovery.

Influence of different pretreated sludge for electricity generation in microbial fuel cells (MFCs) was investigated in this study. Pre-treatment has shown significant improvement in MFC electricity productivity especially from microwave treated sludge. Higher COD reduction in the MFC has been revealed from microwave treated sludge with 55% for total and 85% for soluble COD, respectively. Nonetheless, longer ozonation treatment did not give additional advantage compared to the raw sludge. On the other hand, samples from anodes were analyzed using the 16S rRNA gene-based pyrosequencing technique for microbial community analysis. There was substantial difference in community compositions among MFCs fed with different pretreated sludge. Bacteroidetes was the abundant bacterial phylum dominated in anodes of higher productivity MFCs. These results demonstrate that using waste sludge as the substrate in MFCs could achieve both sludge reduction and electricity generation, and proper pre-treatment of sludge could improve the overall process performance.

Antioxidant activity of different rice extract and the effect on the levels of antioxidant enzyme activity, superoxide dismutase (SOD) and glutathione peroxidase (GPx), vitamin E, lipid peroxidation and liver enzymes in hyperlipidaemia rabbits were investigated. Germinated brown rice (GBR) has the highest antioxidant activity compared to white rice (WR) and brown rice (BR). All rice grains increased the activity of SOD and GPx. However, vitamin E levels increased only in the groups that received the BR and GBR diets. The reduction of lipid peroxidation levels and activity of hepatic enzymes (alanine transferase, ALT and aspartate transaminase, AST) were only significantly observed in the GBR group. In conclusion, GBR supplementation has the greatest impact on increasing antioxidant enzyme activity and vitamin E level and on reducing lipid peroxidation in hypercholesterolaemia rabbit, thereby preventing the formation of atherosclerotic plaques. Furthermore, GBR diet can also reduce the level of hepatic enzymes.

An anaerobic fermentation of food waste was conducted in a 0.5 L bioreactor incubated at a thermophilic temperature of 55 °C to evaluate the effects of different controlled pH values (5.0, 5.5 and 6.0) on biohydrogen production. Effective biohydrogen production was found at controlled pH 5.5 and 6.0 corresponding to lower lactic acid production compared to pH 5.0. It was demonstrated that biohydrogen production from food waste was pH-dependent with hydrogen yields of 79, 76 and 23 mmol H2/L-media/d for pH 5.5, 6.0 and 5.0, respectively. Specific microbial determination for Clostridium sp. and total bacteria quantification were carried out by the fluorescent in-situ hybridization (FISH) technique. The number of Clostridium sp. for acclimatized sludge, fermentation broth at pH 5.0, 5.5 and 6.0 were 2.9 × 108, 3.6 × 108, 7.8 × 108 and 5.4 × 108 cells/ml, respectively. The quantification analysis showed that 92% of the total bacteria belonged to Clostridium sp. from clusters I and XI from the sample at controlled pH 5.5. The denaturing gradient gel electrophoresis (DGGE) bands of the sample after heat-treatment, acclimatization and during fermentation indicated the presence of Bacteroidetes, Caloromator australicus sp. and Clostridium sp.

Canarium odontophyllum Miq. fruit (dabai) is an important food and oil resource for the native people in Sarawak, Malaysia. However, there is little information regarding their oil composition. In this paper, fatty acid compositions, vitamin E contents and physicochemical properties of dabai pulp and kernel oils were studied. These parameters were compared with commercial olive and palm oils. The content of total saturated fatty acid was found to be 44.4% in dabai pulp, kernel (60.8%), palm oil (47.9%) and olive (25.5%) oils. Palmitic, myristic, oleic and linoleic acids were detected in dabai pulp oil (36.1, 5.8, 41.5 and 11.8%) dabai kernel oil (46.4, 9.3, 35.1 and 2.8%), palm oil (33.8, 9.2, 39.7 and 10.9%) and olive oil (9.9, 12.9, 64.4 and 5.1%). Vitamin E was not detected in the dabai pulp oil, while palm oil had the highest vitamin E content, followed by dabai kernel oil and olive oil. In addition, the physicochemical characteristics of dabai oils show better quality than the studied commercial oils. The present study also showed that dabai pulp and kernel oils have good fatty acid composition and a high potential to be developed into healthy cooking oils.