The tropical estuarine ecosystem is fascinating for studying the dynamics of water quality and phytoplankton diversity due to its frequently changing hydrological conditions. Most importantly, phytoplankton is the main supplier of ω3 polyunsaturated fatty acids (PUFA) in the coastal food web for fish as they could not synthesize PUFA. This study evaluated seasonal variations of water quality parameters in the Meghna River estuary (MRE), explored how phytoplankton diversity changes according to hydro-chemical parameters, and identified the major phytoplankton groups as the main source of PUFA for hilsa fish. Ten water quality indicators including temperature, dissolved oxygen, pH, salinity, dissolved inorganic nitrogen (DIN = nitrate, nitrite, ammonia) and phosphorus, dissolved silica and chlorophyll-a were evaluated. In addition, phytoplankton diversity was assessed in the water and hilsa fish gut. Principal component analysis (PCA) was used to analyze the spatio-temporal changes in the water quality conditions, and the driving factors in the MRE. Four main components were extracted and explained 75.4% variability of water quality parameters. The most relevant driving factors were dissolved oxygen, salinity, temperature, and DIN (nitrate, nitrite and ammonia). These variabilities in physicochemical parameters and dissolved inorganic nutrients caused seasonal variations in two major groups of phytoplankton. Peak abundance of Chlorophyta (green algae) occurred in water in nutrient-rich environments (nitrogen and phosphorus) during the wet (36%) season, while Bacillariophyta (diatoms) were dominant during the dry (32%) season that depleted dissolved silica. Thus, the decrease of green algae and the increase of diatoms in the dry season indicated the potential link to seasonal changes of hydro-chemical parameters. The green algae (53.7%) were the dominant phytoplankton group in the hilsa gut content followed by diatoms (22.6%) and both are contributing as the major source of PUFAs for hilsa fish according to the electivity index as they contain the highest amounts of PUFAs (60 and 28% respectively).
In this study, two native duckweeds (Lemna minor and Azolla pinnata) were cultivated in Palm Oil Mill Effluent (POME) to extract nutrients from the effluent. Five grams of A. pinnata and 2 g of L. minor were transferred to 2 L POME (Initial concentrations: 198 mg/L COD, 4.3 mg/L nitrates, pH 9.53, 4 mg/L phosphate, 2.98 mg/L ammonia) with four different dilutions (2.5%, 5%, 10%, 15%) under greenhouse conditions. Samples of POME were taken every two days up to 10 days. Growth parameter, phosphate, ammonia, nitrates, pH, and COD were monitored within 10 days to select the most suitable growth medium for both plants. Results showed that 2.5% POME dilution had positive effect on L. minor growth and A. pinnata (wet weight increased by 8.7 g and 9.8 g, respectively), with all plants able to survive until the final day of exposure. The highest removal of ammonia was accomplished in 5% POME dilution by A. pinnata (98%) and L. minor (95.5%). The maximum phosphate removal was obtained in 10% POME dilution with 93.3% removal by A. pinnata and 86.7% by L. minor. Significant COD removal in 15% POME was obtained by L. minor (78%) and A. pinnata (66%). Both plants responded positively to the phytoremediation process, especially for A. pinnata which showed significant decreases in all parameters. The nutrient extraction by both plants from POME showed a positive effect on growth parameter, which has further promising potential to be used as animal feedstock.
The primary biological treatment method for organic sludge is composting and/or anaerobic digestion, but their product (compost or biogas) is of little economic benefit; therefore, an improved process to produce a high-value product is required to make sludge management more sustainable. Maximizing NH3 gas recovery during composting processes has the potential benefit of producing high-value microalgal biomass. However, the majority of produced ammonia does not evaporate as NH3 gas but retains as NH4+-N in the compost after fermentation. The present study investigates the effects of the timing of Ca(OH)2 dosing (on days 2, 5, and 9), and the Ca(OH)2 dose (1.1-2.6 mmol/batch), on lab-scale thermophilic composting of anaerobic sludge. The effects on NH3 recovery, organic matter degradability, and microbial activity are evaluated. Ca(OH)2 dosing immediately improved the emission of NH3, with yields 50-69% higher than those under control conditions. The timing of the dosing did not influence NH3 recovery or organic matter degradability. Higher Ca(OH)2 doses resulted in higher NH3 recovery, while microbial activity was temporarily and marginally inhibited. The pH of the compost reached 10-11.5 but quickly dropped to 8-8.5 within a day, probably because of neutralization of Ca(OH)2 by the emitted CO2 and release of NH3, which maintained the microbial activity. The present study indicated that Ca(OH)2 dosing would be useful to apply during thermophilic composting for NH3 recovery to cultivate high-value microalgal biomass, which enables this process to obtain a more economic benefit.
The novel immobilized microbial granules (IMG) shows a significant effect of nitrification for freshwater aquaculture. However, there is lack of evaluation study on the performance of nitrification at high salinity due to the concentration of recycled water or seawater utilization. A laboratory scale moving bed bioreactor (MBBR) with IMG was tested on recycled synthetic aquaculture wastewater for the nitrification at 2.5 mg/L NH3-N daily. The results indicated that IMG showed a high salinity tolerance and effectively converted ammonia to nitrate up to 92% at high salinity of 35.0 g/L NaCl. As salinity increased from near zero to 35.0 g/L, the microbial activity of nitrite oxidation bacteria (NOB) in the IMG decreased by 86.32%. The microbial community analysis indicated that salinity significantly influenced the community structure. It was found that Nitrosomonas sp. and Nitrospira sp. were the dominant genera for ammonia oxidation bacteria (AOB) and NOB respectively at different salinity levels.
This paper studies about water obtained from fish pond of fisheries research centre. Usual water
quality parameters such as pH, COD, Turbidity and Ammonia content were analyzed before and
after irradiation. Electron beam irradiation was used to irradiate the water with the dose 100 kGy,
200 kGy and 300 kGy. Only high dose was applied on this water as only a limited amount of
samples was supplied. All the parameters indicated a slight increase after irradiation except for the
ammonia content, which showed a gradual decrease as irradiation dose increases. Sample
condition was changed before irradiation in order to obtain more effective results in the following
batch. The water sample from fisheries was diluted with distilled water to the ratio of 1:1.This was
followed with irradiation at 100 kGy, 200 kGy and 300 kGy. The results still showed an increase in
all parameters after irradiation except for ammonia content. For the following irradiation batch,
the pH of the sample was adjusted to pH 4 and pH 8 before irradiation. For this sample the
irradiation dose selected was only 100 kGy. A higher value of ammonia was observed for the
sample with pH 4 after irradiation. Other parameters were almost the same as the first two batches
Development of thermophilic composting for maximizing NH3 gas recovery would enable the production of a nitrogen source which is free from pathogen/heavy metal, for the cultivation of high-value microalgae. The present study examined the effect of NH3 recovery, nitrogen mass balance, and microbial community dynamics on thermophilic composting of shrimp aquaculture sludge. The emission of NH3 gas at 60 and 70 °C was 14.7% and 15.6%, respectively, which was higher than that at 50 °C (9.0%). The nitrogen mass balance analysis revealed that higher temperatures enhanced the solubilization of non-dissolved nitrogen and liberation of NH3 gas from the produced NH4+-N. High-throughput microbial community analysis revealed the shift of the dominant bacterial group from Bacillus to Geobacillus with the rise of composting temperature. In conclusion, thermophilic composting of shrimp aquaculture sludge at 60-70 °C was the most favorable condition for enhancing NH3 gas recovery.
Increasing aquaculture cultivation produces large quantities of wastewater. If not handled properly, it can have negative impacts on the environment. Constructed wetlands (CWs) are one of the phytoremediation methods that can be applied to treat aquaculture effluent. This research was aimed at determining the performance of Cyperus rotundus in removing COD, BOD, TSS, turbidity, ammonia, nitrate, nitrite, and phosphate from the batch CW system. Treatment was carried out for 30 days with variations in the number of plants (10, 15, and 20) and variations in media height (10, 12, and 14 cm). The result showed that aquaculture effluent contains high levels of organic compounds and nutrients, and C. rotundus can grow and thrive in 100% of aquaculture effluent. Besides that, the use of C. rotundus in CWs with the effect of numbers of plants and media height showed performance of COD, BOD, TSS, turbidity, ammonia, nitrate, nitrite, and phosphate with 70, 79, 90, 96, 64, 82, 92, and 48% of removal efficacy, respectively. There was no negative impact observed on C. rotundus growth after exposure to aquaculture effluent, as indicated by the increase in wet weight, dry weight, and growth rate when compared to the control. Thus, adding aquaculture effluent to CWs planted with C. rotundus supports the growth and development of plants while also performing phytoremediation.
This study determined the most effective microbes acting as ammonia-oxidising (AOB) and manganese-oxidising bacteria (MnOB) for the simultaneous removal of ammonia (NH(4)(+)-N) and manganese (Mn(2+)) from water. Two conditions of mixed culture of bacteria: an acclimatised mixed culture (mixed culture: MC) in a 5-L bioreactor and biofilm attached on a plastic medium (stages of mixed culture: SMC) in a biological aerated filter were isolated and identified using Biolog MicroSystem and 16S rRNA sequencing. A screening test for determining the most effective microbe in the removal of NH(4)(+)-N and Mn(2+) was initially performed using SMC and MC, respectively, and found that Bacillus cereus was the most effective microbe for the removal of NH(4)(+)-N and Mn(2+). Moreover, the simultaneous NH(4)(+)-N and Mn(2+) removal (above 95% removal for both NH(4)(+)-N and Mn(2+)) was achieved using a biological aerated filter under various operating conditions. Thus, the strain could act as an effective microbe of AOB and a MnOB for the simultaneous removal of NH(4)(+)-N and Mn(2+).
Nitrogen-rich materials such as poultry litter (PL) contributes to substantial N and C loss in the form of ammonia (NH3) and carbon dioxide (CO2) during composting. Biochar can act as a sorbent of ammonia (NH3) and CO2 emission released during co-composting. Thus, co-composting poultry litter with rice husk biochar as a bulking agent is a good technique to mitigate NH3 volatilization and CO2 emission. A study was conducted to evaluate the effects of composting the mixtures of poultry litter with rice husk biochar at different ratios on NH3 and CO2 emissions. Four mixtures of poultry litter and rice husk biochar at different rate were composted at 0:1, 0.5:1, 1.3:1 and 2.3:1 ratio of rice husk biochar (RHB): poultry litter (PL) on a dry weight basis to achieve a suitable C/N ratio of 15, 20, 25, and 30, respectively. The results show that composting poultry litter with rice husk biochar can accelerate the breakdown of organic matter, thereby shortening the thermophilic phase compared to composting using poultry litter alone. There was a significant reduction in the cumulative NH3 emissions, which accounted for 78.38%, 94.60%, and 97.30%, for each C/N ratio of 20, 25, and 30. The total nitrogen (TN) retained relative was 75.96%, 85.61%, 90.24%, and 87.89% for each C/N ratio of 15, 20, 25, and 30 at the completion of composting. Total carbon dioxide lost was 5.64%, 6.62%, 8.91%, and 14.54%, for each C/N ratio of 15, 20, 21, and 30. In addition, the total carbon (TC) retained were 66.60%, 72.56%, 77.39%, and 85.29% for 15, 20, 25, and 30 C/N ratios and shows significant difference as compared with the initial reading of TC of the compost mixtures. In conclusion, mixing and composting rice husk biochar in poultry litter with C/N ratio of 25 helps in reducing the NH3 volatilization and CO2 emissions, while reducing the overall operational costs of waste disposal by shortening the composting time alongside nitrogen conservation and carbon sequestration. In formulating the compost mixture with rice husk biochar, the contribution of C and N from the biochar can be neglected in the determination of C/N ratio to predict the rate of mineralization in the compost because biochar has characteristic of being quite inert and recalcitrant in nature.
A digestibility study was conducted to evaluate the effects of supplementing mulberry foliage and urea rice-bran as a source of fermentable energy and protein to 12 sheep fed diets based on urea-treated rice straw (TRS). The three dietary treatments were: T1, TRS with mulberry; T2, TRS with 50% mulberry replaced with rice bran and urea; and T3, TRS with rice bran and urea. The study was arranged in a completely randomized design with four replications for each treatment. The sheep were fed one of the three diets and the supplements were offered at 1.2% of the body weight (BW) and the TRS was provided ad libitum. There were no differences (p>0.05) among the three treatment groups with respect to dry matter (DM) intake (76.8±4.2 g/kg BW(0.75)) and DM, organic matter (OM), and crude protein (CP) digestibility (55.3±1.22; 69.9±0.85; 46.3±1.65% respectively for DM, OM, and CP). The digestibility of fiber (neutral detergent fiber [NDF] and acid detergent fiber) was significantly lower (p<0.05) for T3 (46.2 and 46.6 respectively) compared to T1 (55.8 and 53.7 respectively) and T2 (54.1 and 52.8 respectively). Nitrogen (N) intake by sheep on diet T3 was significantly (p<0.05) higher than sheep fed diet T1. However, N balance did not differ among the three diets (3.0±0.32 g/d). In contrast, the rumen ammonia (NH3-N) concentrations in sheep fed T2 and T3 were significantly (p<0.05) higher than in sheep fed T1. The NH3-N concentrations for all three diets were above the critical value required for optimum rumen microbial growth and synthesis. Total volatile fatty acid concentrations were highest (p<0.05) in T1 (120.3 mM), whilst the molar proportion of propionic acid was highest in T3 (36.9%). However, the microbial N supply in sheep fed T1 and T3 was similar but was significantly (p<0.05) higher than for sheep fed T2. It was concluded that mulberry foliage is a potential supplement of fermentable energy and protein for sheep fed TRS based diet. The suggested level of supplementation is 1.2% of BW or 32% of the total diet since it resulted in similar effects on the intake of DM, OM, and NDF, digestibility of DM, OM, and CP, N utilization and microbial supply when compared to rice bran and urea supplementation.
Nitric oxide (NO) is involved in many pathophysiological processes in the brain. NO is synthesized from arginine by nitric oxide synthase (NOS) enzymes. Citrulline formed as a by-product of the NOS reaction, can be recycled to arginine by successive actions of argininosuccinate synthetase (ASS) and argininosuccinate lyase (ASL) via the citrulline-NO cycle. Hyperammonemia is known to cause poorly understood perturbations of the citrulline-NO cycle. To understand the role of citrulline-NO cycle in hyperammonemia, NOS, ASS, ASL and arginase activities, as well as nitrate/nitrite (NOx), arginine, ornithine, citrulline, glutamine, glutamate and GABA were estimated in cerebral cortex (CC), cerebellum (CB) and brain stem (BS) of rats subjected to acute ammonia toxicity. NOx concentration and NOS activity were found to increase in all the regions of brain in acute ammonia toxicity. The activities of ASS and ASL showed an increasing trend whereas the arginase was not changed. The results of this study clearly demonstrated the increased formation of NO, suggesting the involvement of NO in the pathophysiology of acute ammonia toxicity. The increased activities of ASS and ASL suggest the increased and effective recycling of citrulline to arginine in acute ammonia toxicity, making NO production more effective and contributing to its toxic effects.
Oil palm empty fruit bunch (OPEFB) fibre is widely available in Southeast Asian countries and found to have 60% (w/w) sugar components. OPEFB was pretreated using the ammonia fibre expansion (AFEX) method and characterised physically by the Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy. The results show that there were significant structural changes in OPEFB after the pretreatment step, and the sugar yield after enzymatic hydrolysis using a cocktail of Cellic Ctec2® and Cellic Htec2® increased from 0.15gg(-1) of OPEFB in the raw untreated OPEFB sample to 0.53gg(-1) of OPEFB in AFEX-pretreated OPEFB (i.e. almost a fourfold increase in sugar conversion), which enhances the economic value of OPEFB. A biohydrogen fermentability test of this hydrolysate was carried out using a locally isolated bacterium, Enterobacter sp. KBH6958. The biohydrogen yield after 72h of fermentation was 1.68mol H2 per mol sugar. Butyrate, ethanol, and acetate were the major metabolites.
The effects of dietary protein level on the growth performance and ammonia excretion of the leopard coral grouper,
Plectropomus leopardus were investigated for eight weeks. Fish were fed diets with 40, 45, 50, 55 and 60% crude protein
levels in separate recirculating systems. Fish fed with the 50% crude protein containing diet showed the best ingestion
rate, which was significantly higher than that found in the other groups. As the dietary protein level increased, the
specific growth rate increased significantly and it reached the highest level at 50% crude protein containing diet. Based
on the results of all measured parameters 50% protein containing diet was the best among all test diets. The regression
equation for dietary protein level versus ammonia excretion indicated that the optimal dietary protein level with the
least ammonia excretion was 53.14%. More research is still needed to elucidate the effects of 53.14% crude protein
containing diet on the specific growth rate, feed conversion ratio, protein efficiency ratio and ingestion rate of leopard
coral grouper before recommending this level. Until then, 50% protein containing diet can be recommended for leopard
coral grouper culture in the recirculation system.
Marudu Bay, north coast of Sabah is characterized with mesotrophic water body and typical environmental parameters
throughout the year. The current study was undertaken to evaluate the effect of environmental parameters and nutrients
in mesotrophic water on the occurrence and distribution of potentially harmful phytoplankton species. The samplings
were conducted over a period of thirteen months, covering southwest monsoon (SWM), inter-monsoon (IM), and northeast
monsoon (NEM), at ten stations throughout the bay. Physical parameters (temperature, salinity, pH, dissolved oxygen,
current speed and secchi depth), biological parameters (cell densities of phytoplankton) and chemical parameters
(phosphate, nitrate, silicate and ammonia) were examined. The results indicated at least eight potentially harmful
phytoplankton species (Dinophysis caudata, D. miles, Ceratium furca, C. fursus, Prorocentrum micans, P. sigmoides, P.
triestinum and Pseudo-nitzschia sp.) were detected in north coast of Sabah. However, the potentially harmful phytoplankton
species contributed only about 1.3% of the total phytoplankton community. Under nutrient deprivation conditions, the
potentially harmful phytoplankton species distribution was mainly influenced by the ability to utilize other nitrogen
sources, cell mobility and toleration to low nutrients environments.
Thermal stratification in lakes is an important natural process that can have a significant effect on the water resource quality. The potential changes in chemical contents in water resulting from stratification are the production of ammonia, sulphides and algal nutrients and the increasing concentrations of iron and manganese. One of the water supply reservoirs located in Johor, Malaysia facing with high iron and manganese concentrations associated with the period of stratifications. This study showed that the level of thermal stratification in the reservoir varied at different time of the year. During the strongest period of stratification, the dissolved oxygen content was found to diminish significantly with depth and iron and manganese were recorded at the highest concentrations. Although significant period of rainfalls contributed to the natural destratification of reservoir, lower concentrations of iron and manganese only remained for a shorter period before the concentrations continued to increase with the onset of the thermal stratification. A good understanding on the behaviour of the reservoir may help to identify several measures for the improvement of water quality.
The present study investigated the efficiency of aerobic granular sludge (AGS) technology in treating effluent from soy sauce industry which is categorized as a high strength wastewater. The combination of anaerobic and aerobic granulation technology in SBR system was used in this study which was efficiently treated COD from the soy sauce wastewater where 87% of removal was achieved. Ammonia and colour was removed at a maximum of 87 and 76%, respectively, in the SBR system. Matured, dense and compact granules with 2.5 mm in diameters were developed with a good settling velocity (45 m/h) and 28 mL/gSS of sludge volume index (SVI). Hence, AGS technology was proven as an excellent treatment for soy sauce wastewater for being discharge into the environment, as the effluent was treated in one biological reactor with high hydraulic and organic loadings besides less production of sludge. In this study, the capabilities of AGS technology in treating relatively higher concentration of organic impurities present in the soy sauce wastewater were demonstrated.
Endophytes are novel sources of natural bioactive compounds. This study seeks endophytes that produce the anticancer enzyme l-asparaginase, to harness their potential for mass production. Four plants with anticancer properties; Cymbopogon citratus, Murraya koenigii, Oldenlandia diffusa and Pereskia bleo, were selected as host plants. l-Asparaginase-producing endophytes were detected by the formation of pink zones on agar, a result of hydrolyzes of asparagine into aspartic acid and ammonia that converts the phenol red dye indicator from yellow (acidic condition) to pink (alkaline condition). The anticancer enzyme asparaginase was further quantified via Nesslerization. Results revealed that a total of 89 morphotypes were isolated; mostly from P. bleo (40), followed by O. diffusa (25), C. citratus (14) and M. koenigii (10). Only 25 of these morphotypes produced l-asparaginase, mostly from P. bleo and their asparaginase activities were between 0.0069 and 0.025 μM mL(-1) min(-1). l-Asparaginase producing isolates were identified as probable species of the genus Colletotrichum, Fusarium, Phoma and Penicillium. Studies here revealed that endophytes are good alternative sources for l-asparaginase production and they can be sourced from anticancer plants, particularly P. bleo.
Butyrylcholinesterase (BChE) efficiently hydrolyzes acetylcholine (ACh) at high concentrations when acetylcholinesterase (AChE) is substrate-inhibited. Recent studies have shown that BChE also has a function that is independent of ACh, but it has not been fully explored. Low BChE expression is accompanied with higher stress-induced aggression and ghrelin levels in stress models, and BChE knockout mice exhibit cognitive and memory impairments. However, the role of BChE in posttraumatic stress disorder (PTSD) remains unclear. In the present study, we investigated the role of BChE in contextual fear memory and its regulatory effect on the expression of factors related to the glutamate (Glu)-glutamine (Gln) cycle via knockdown studies. We used AAVs and lentiviruses to knockdown BChE expression in the mouse hippocampal CA1 region and C8D1A astrocytes. Our behavioral data from those mice injected with AAV-shBChE in the hippocampal CA1 region showed strengthened fear memory and increased dendritic spine density. Elevated Glu levels and glutamine synthetase (GS) enzyme activity were detected in contextual fear conditioned-BChE knockdown animals and astrocytes. We observed that an AAV-shBChE induced lowering of BChE expression in the hippocampus CA1 region enhanced contextual fear memory expression and promoted the astrocytic Glu-Gln cycle but did not elevate ACh-hydrolyzing activity. This study provides new insight into the regulatory role of BChE in cognition and suggests potential target for stress-related psychiatric disorder such as PTSD where patients experience fear after exposure to severe life-threatening traumatic events.
Exposure to TEX-OE®, a patented extract of the prickly pear cactus (Opuntia ficus indica) containing chaperone-stimulating factor, was shown to protect common carp, Cyprinus carpio L., fingerlings against acute ammonia stress. Survival was enhanced twofold from 50% to 95% after exposure to 5.92 mg L(-1) NH(3) , a level determined in the ammonia challenge bioassay as the 1-h LD50 concentration for this species. Survival of TEX-OE®-pre-exposed fish was enhanced by 20% over non-exposed controls during lethal ammonia challenge (14.21 mg L(-1) NH(3) ). Increase in the levels of gill and muscle Hsp70 was evident in TEX-OE®-pre-exposed fish but not in the unexposed controls, indicating that application of TEX-OE® accelerated carp endogenous Hsp70 synthesis during ammonia perturbation. Protection against ammonia was correlated with Hsp70 accretion.
The cell-free extract of locally isolated Rhodococcus UKMP-5M strain was used as an alternative to develop greener and cost effective cyanide removal technology. The present study aims to assess the viability of the cell-free extract to detoxify high concentrations of cyanide which is measured through the monitoring of protein concentration and specific cyanide-degrading activity. When cyanide-grown cells were subjected to grinding in liquid nitrogen which is relatively an inexpressive and fast cell disruption method, highest cyanide-degrading activity of 0.63 mM min(-1) mg(-1) protein was obtained in comparison to enzymatic lysis and agitation with fine glass beads. The cell-free extracts managed to degrade 80% of 20 mM KCN within 80 min and the rate of cyanide consumption increased linearly as the concentration of protein was raised. In both cases, the addition of co-factor was not required which proved to be advantageous economically. The successful formation of ammonia and formate as endproducts indicated that the degradation of cyanide by Rhodococcus UKMP-5M proceeded via the activity of cyanidase and the resulting non-toxic products are safe for disposal into the environment. Further verification with SDS-PAGE revealed that the molecular weight of the active enzyme was estimated to be 38 kDa, which is consistent with previously reported cyanidases. Thus, the utilization of cell-free extracts as an alternative to live microbial in cyanide degradation offers numerous advantageous such as the potential to tolerate and degrade higher concentration of cyanide and total reduction in the overall cost of operation since the requirement for nutrient support is irrelevant.