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An effective biosurfactant producer and extremophiles bacteria, Bacillus cereus KH1, was isolated from textile effluent and the biosurfactant was produced using molasses as the sole carbon source. Growth parameters such as pH, temperature, salinity and concentration of molasses were optimised for decolourising the textile effluent with 24-h incubation. The biosurfactant property of B. cereus KH1 was evaluated based on haemolytic activity, oil displacement technique, drop-collapsing test and emulsification index. The results of the produced biosurfactant showed a positive reaction in haemolytic activity, oil displacement technique, drop-collapsing test and exhibiting a 67% emulsification index. The cell-free broth was stable in 40 °C pH 7, 7% salinity and 7% molasses. Thin-Layer Chromatography and Fourier Transform Infrared Spectroscopy analysis revealed that the biosurfactant was a lipopeptide with a yield 2.98 g L

Improvements in biohydrogen production from palm oil mill effluent (POME) has been achieved by optimizing the physicochemical conditions, using an enriched sludge as inoculum. Enrichment of biohydrogen-producing communities in the sludge was first carried out by heat treatment and acclimatization to POME. Response surface methodology (RSM) was then used for optimizing the operational parameters. The factors investigated were temperature, initial pH, and inoculum concentration. The output responses were evaluated based on the biohydrogen yield (YH2), biohydrogen production rate (RH2), and COD removal efficiency. Microbial analysis of the enriched sludge at 100% POME concentration revealed the abundance of the Firmicutes phylum (98%) among the Bacteria population, with Clostridiaceae as the most abundant family. Archaea were inhibited at both 30% and 100% POME concentration. The optimum operational parameters generated by the RSM model were 34.7 °C, pH 5.81, and inoculum size of 14.22% (v/v), with the following predicted outcomes: YH2 of 42.29 mL H2 gCOD−1, RH2 of 106.09 mL L−1 h−1, and COD removal efficiency of 23.66%. Meanwhile, the experimental data generated were as follows: YH2 of 41.18 mL H2 gCOD−1, RH2 of 109 mL L−1 h−1, and COD removal efficiency of 25.96%. The process reliability was further demonstrated in a larger (2.5 L) continuously stirred-tank reactor, with the maximum biohydrogen yield obtained of 282 mL H2 gCOD−1 and COD removal efficiency of 35%. Butyric and acetic acids were the dominant soluble metabolites produced. These findings suggest that the RSM model generated was successfully used to optimize biohydrogen production from POME using enriched anaerobic digested sludge.

The growing demand for nanocellulose materials synthesized from renewable sources has increased over the years (Kargarzadeh et al. 2012). Nanocelluloses are abundant, economical, biodegradable, and...

High resolution Chlorophyll-a (Chl-a) can indicate the trophic status of the water and provide useful information on optical features of water body in water quality monitoring. Remote sensing has great potential to offer the spatial and temporal coverage needed. Over the last decades the Sea WIFS and MODIS were applied, but not suitable due to the low spatial resolution for monitoring Chl-a in coastal area. However, the retrieval of Chl-a in the coastal region is usually challenging due to the other in-water substances regardless of Chl-a, hence resulting in the satellite retrieved Chl-a overestimation. By the advancement of the Sentinel-2 and Landsat 8 satellites, continuous high resolution optical imageries have served for remarkable coastal mapping capability thanks to the spectroscopic capability certain spectral bands and as high as 10-meter spatial resolution. This paper aims to evaluate the performance of the SEADASS and SNAP processor for Chl-a estimation from the Operational Land Imager (OLI)and MultiSpectral Instrument(MSI) data in Johor waters. The representative models, in standard algorithm OC3and C2RCC, were adapted to retrieve Chl-a concentration. The statistical regression has shown that these algorithms give an acceptable Chl-a estimation at medium and high resolution with R2=0.44 from OC3and R2=0.55from C2RCC comparing to the in-situ data. Despite of the spatial, temporal and spectral variability, this paper shows that OLI and MSI could provide Chl-a mapping capability at suitable Chl-a estimation techniques.

To date, there is sparse information for the genus Robertkochia with Robertkochia marina CC-AMO-30DT as the only described member. We report here a new species isolated from mangrove soil collected at Malaysia Tanjung Piai National Park and perform polyphasic characterization to determine its taxonomic position. Strain CL23T is a Gram-negative, yellow-pigmented, strictly aerobic, catalase-positive and oxidase-positive bacterium. The optimal growth conditions were determined to be at pH 7.0, 30–37 °C and in 1–2 % (w/v) NaCl. The major respiratory quinone was menaquinone-6 (MK-6) and the highly abundant polar lipids were four unidentified lipids, a phosphatidylethanolamine and two unidentified aminolipids. The 16S rRNA gene similarity between strain CL23T and R. marina CC-AMO-30DT is 96.67 %. Strain CL23T and R. marina CC-AMO-30DT clustered together and were distinguished from taxa of closely related genera in 16S rRNA gene phylogenetic analysis. Genome sequencing revealed that strain CL23T has a genome size of 4.4 Mbp and a G+C content of 40.72 mol%. Overall genome related indexes including digital DNA–DNA hybridization value and average nucleotide identity are 17.70 % and approximately 70%, below the cutoffs of 70 and 95%, respectively, indicated that strain CL23T is a distinct species from R. marina CC-AMO-30DT. Collectively, based on the phenotypic, chemotaxonomic, phylogenetic and genomic evidences presented here, strain CL23T is proposed to represent a new species with the name Robertkochia solimangrovi sp. nov. (KCTC 72252T=LMG 31418T). An emended description of the genus Robertkochia is also proposed.

This work reports the inclusion of crocin (an active agent of saffron) into bacterial nanocellulose (BNC) membrane for transdermal drug delivery. The BNC showed good uptake of the crocin based on the swelling studies and vibrational peaks of the FTIR spectra. Surface morphology of the crocin loaded BNC showed that the fibrous nano feature was still intact with no fiber damages. The crocin release via direct dissolution showed typical burst release. Franz diffusion test revealed stable and prolong drug permeation. Partition coefficient of the BNC-crocin via mice epidermal skin diffusion was found to be 2.44×10−4 cm−2 min−1 with the average mass flux of 0.53 cm−2 min−1. This facile method of utilizing BNC for the carrier of crocin can be useful for administrating other water soluble active compound. Thus BNC opens up choices for the delivery of crocin for medicinal purposes.

This study was conducted to explore the potential of isolating bionanocellulose (BNC) producing bacteria from tapioca wastewater. A total of ten bacteria were successfully isolated and only one isolate named BPNC 3 produced white gelatinous materials in Hestrin and Schramm (HS) medium believed to be the BNC. According to 16S rRNA analysis, bacterium BPNC 3 was identified as Asaia sp. The BNC produced by Asaia sp. BPNC3 was characterized via Fourier transformed-infrared spectroscopy (FTIR) and Field-emission scanning electron microscope (FESEM). The FTIR spectrum showed the presence of two signature peaks at 3276.69 cm-1 and 2923.99 cm-1 indicative of nanocellulosic material. The FESEM micrograph showed characteristics of network fibrils typically present in nanocellulose structure.

The main purpose of this study is to provide information on the biochemical composition of the total lipid extract of three different native freshwater microalgae namely Acutodesmus obliquus CN01, Chlorella sp. Carolina-15-2069, and Chlorella vulgaris NIES-1269 at different growth phases, cultured under standardized conditions that will be useful for commercialization purposes due to the content of α-linolenic acid (ALA), a type of omega-3 fatty acids. We monitored growth, biomass accumulation, chlorophyll content, lipid content and fatty acids composition in all three freshwater microalgae. In addition, this study seeks to throw some light on the lipid content of a newly isolated freshwater green alga Acutodesmus obliquus CN01 which have shown to give significant quantities of ALA, an added nutritional value to this microalga oil. Acutodesmus obliquus CN01 exhibited the fastest growth rate among the three microalgae used. Biomass was shown to be enhanced in the nitrogen enrichment medium. The outcomes from this study indicated that newly isolated Acutodesmus obliquus CN01 from Malaysia cultured under normal condition showed fast growth rate with high lipid content and also high ALA content. Therefore, from this study, Acutodesmus obliquus CN01 was identified as species of choice to be further explored for its potential to produce omega-3 fatty acids.

The global rise in demand for fats and oil has made the palm oil industry grown tremendously over the last decades in countries like Indonesia, Malaysia, and Thailand. Malaysian agro-industrial sector alone accounts for about 51% of the world’s palm oil production and 62% of the world’s export. The sector has generated billions of dollars in revenues, and tonnes of wastes too. Palm oil mill effluent (POME) is the most abundant waste generated during the crude oil extraction process. Efficient and effective POME treatment technologies are still being actively investigated. POME has great potential as a substrate for biohydrogen production due to the high content of degradable organic matter. Dark fermentation, among the various biological processes for biohydrogen production, is highly favored due to the lower cost and low energy requirement. However, achieving a high biohydrogen yield is the main challenge, due to the co-production of organic acids. Additional treatment steps using bioelectrochemical systems (BES), such as microbial electrolysis cell (MEC), can provide the much-needed solution. Enhanced biohydrogen production can potentially be achieved when dark fermentation is coupled with MEC, with better POME treatment. Microbial fuel cell (MFC) can provide additional treatment step, with simultaneous electricity generation. This chapter reviews the various dark fermentation technologies that have been employed in producing biohydrogen from POME, the methods employed to improve biohydrogen yield, the advancements in BES, and the potential integration with dark fermentation for enhanced biohydrogen production.

Aim: Biological flocculants has been widely used around the world to replace the usage of synthetic flocculants for wastewater treatment.Anew green technology using biological flocculant known as biofloc system was developed which offers zero water exchanged, low feed conversion ratio (FCR) and high nutritional profile. This study was conducted to determine the most potential bioflocculant-producing bacteria isolated from biofloc sampleinPacific Whiteleg shrimp,P. vannameiculture pond. Methodology: Biofloc sample was collected using Imhoff cone and bacteria was isolated. The most abundant bacteria isolated throughout P. vannamei culture period was selected for screening of bioflocculant-producing bacteria usingYPG medium and flocculation activity using floc-jar test. Results: Screening of bioflocculant-producing bacteria showed that B. infantis, N. aquimarinus, B. cereus, H. venusta, Pseudoalteromonas sp., and B. safensis were characterized as highly mucoid and ropy colony morpologies. The highest flocculation activity with 93% was showed by B. infantis followed by N. aquimarinus (91%), B. cereus (87%), H. venusta (79%), Pseudoalteromonas (78%), while the lowest flocculation activity was showed byB. safensiswith 69%. Interpretation: As bacteria grew, extracellular polymeric substances (EPS) produced were involved in flocculation process. Each bacteria produced different EPS composition which differed their ability in flocculation process. Therefore, bacteria with high flocculation activity are potentially used as inoculum to increase flocculation processinbiofloc production.

The Johor Strait has experienced rapid development of various human activities and served as the main marine aquaculture area for the two countries that bordered the strait. Several fish kill incidents in 2014 and 2015 have been confirmed, attributed to the algal blooms of ichthyotoxic dinoflagellates; however, the cause of fish kill events after 2016 was not clarified and the causative organisms remained unknown. To clarify the potential cause of fish kills along the Johor Strait, a 1-year field investigation was conducted with monthly sampling between May 2018 and April 2019. Monthly vertical profiles of physical water parameters (temperature, salinity, and dissolved oxygen levels) were measured in situ at different depths (subsurface, 1 m, 5 m, and 8 m) depending on the ambient depth of the water column at the sampling stations. The spatial-temporal variability of macronutrients and chlorophyll a content was analyzed. Our results showed that high chlorophyll a concentration (up to 48.8 μg/L) and high biomass blooms of Skeletonema, Chaetoceros, Rhizosolenia, and Thalassiosira were observed seasonally at the inner part of the strait. A hypoxic to anoxic dead zone, with the dissolved oxygen levels ranging from 0.19 to 1.7 mg/L, was identified in the inner Johor Strait, covering an estimated area of 10.3 km2. The occurrence of high biomass diatom blooms and formation of the hypoxic-anoxic zone along the inner part Johor Strait were likely the culprits of some fish kill incidents after 2016.

One of the most abundant dyes that are used extensively in the textile manufacturing are azo dyes, which may endanger water bodies since incomplete breakdown of dyes may cause mutagenic and carcinogenic compounds to persist. In this study, BAC-ZS, bacterial mixed culture consisting of three acclimatised decolourising bacteria were grown as biofilm onto macrocomposites. Different time duration between 3 to 14 days of biofilm development was studied to determine the density of biofilm attached onto macrocomposites. Sequencing batch reactors (SBRs) were set up for raw textile wastewater treatment to investigate the effectiveness of the treatment with and without the presence of biofilm (control). The treatment was performed under facultative anaerobic-aerobic condition for 20 days continuously with 48-hour of hydraulic retention time (HRT) cycle (consisting both conditions). Colour and chemical oxygen demand (COD) were monitored throughout the treatment process. Results showed that the colour and COD removal by the developed biofilm were 78.6 ± 1.4% and 76.4 ± 1.12% from initial values of 1400 ADMI and 660 mg/L, respectively while only 47.9 ± 0.9% colour and 38.0 ± 1.5% COD removal for the control. In conclusion, the biofilm of BAC-ZS mixed culture coated onto macrocomposites showed potential applications in the treatment of raw textile wastewater.

Recently, attention has been given to nanocellulose produced by bacteria due to its unique properties and environmentally friendly nature when compared with plant cellulose. Bacterial nanocellulose (BNC) producing isolate was successfully isolated from rotten fruits via dilution and spread plates method. Based on the biochemical characterisation and molecular analysis of the 16S rDNA gene, the isolate was identified as Gluconacetobacter xylinus BCMZ sp. Nanocellulose productivity was confirmed by the formation of the white gelatinous layer between air/liquid surfaces when the culture was cultivated under a stationary condition at 30°C. Successful purification of nanocellulose was achieved using alkaline treatment method. The Fourier transformed infrared spectrum showed a characteristics band signature of pure nanocellulose, by displaying strong absorption peaks at 3335.36 and 2901.40 cm(−1) representing carbonyl and carbon–hydrogen bonding, respectively. Morphological characteristics of the BNC were determined by scanning electron microscopy (SEM). Elemental analysis of BNC was determined by energy dispersive X‐ray (SEM/EDX) analysis. The isolates BCZM showed significant nanocellulose production ability with a high degree of purity when compared with plant nanocellulose. BNC purification using 1 M NaOH solution is effective and eco‐friendly with no indication of recalcitrant formation as commonly found in plant nanocellulose purification steps.

Textile dyes are recalcitrant molecules and contain a high level of chemicals and colour which poses a serious challenge to surrounding environments. Therefore, this study aims to produce biosurfactant and investigate the synergistic action on decolourisation of textile dyes by the combination of bacteria and biosurfactant. An effective dye degrading strain and biosurfactant-producer, Kurthia gibsonii KH2, was isolated from textile wastewater using molasses as the only source of carbon and energy. The isolates were identified and screened for biosurfactant production using haemolytic activity, oil spreading technique, drop collapse test and emulsification index. Fourier Transform Infrared Spectrum (FTIR) and Thin Layer Chromatography (TLC) analyses were carried out to detect the type of biosurfactant. The effect of different physicochemical parameters on textile wastewater decolourisation was assessed within 24 h. The Kurthia gibsonii KH2 showed positive results for haemolytic activity, oil spreading technique, and drop collapse test. The emulsification test (E24) revealed that Kurthia gibsonii KH2 had a higher emulsification index of 63%. FTIR and TLC analyses indicated that the biosurfactant was a lipopeptide and was formed with a yield of 2 gL −1. The synergistic activity of Kurthia gibsonii KH2 and lipopeptide biosurfactant resulted in decolourisation levels of 85% at 100 mg/L concentration and pH 7 was recorded at 168 h of incubation. The high attributes of these combinations and the phytotoxicity tests implied that the metabolites were less toxic, making it a promising option for the biodecolourisation and biodegradation of industrial textile wastewater and various environmental conditions.

Silver (Ag)-based materials are widely used as effective antibacterial agents for a wide spectrum of bacteria. There is a great challenge to reduce the amount of Ag in Ag-based materials without limiting its antibacterial activity. Herein, the Ag-zeolite NaY (50% from its cation exchange capacity) was functionalized with 3-aminopropyltriethoxysilane to produce an amine functionalized, Ag-zeolite NaY. The results showed that the functionalization of Ag-zeolite NaY improved its antibacterial activity against a wide spectrum of bacteria (Escherichia coli ATCC11229 and Staphylococcus aureus ATCC6538), especially in solutions containing electrolyte (saline solution), although it has a lower surface area, pore volume and amount of Ag released compared to those of zeolite NaY and Ag-zeolite NaY. Thus, the functionalization of Ag-based materials is a promising approach to reducing the amount of Ag required in Ag-based material while improving its antibacterial activity.

Since the photosynthetic process offers a natural way of sequestering carbon dioxide (CO 2 ) from industrial wastewater treatment such as the ponding system to treat palm oil mill effluent (POME), microbial granules possessing photosynthetic pigments were developed in a sequencing batch reactor (SBR) system using POME. POME from the last pond was used as source of nutrients for the biogranulation process. The developed microbial granules had shown the potential of retaining high accumulation of biomass concentration in the reactor (6.90–8.25 g L −1 ), good settling properties (18.0–103.0 m h −1 ) and improvement in size collected ranging from 0.3 to 2.36 mm as well as physical strength at integrity coefficient of 2% with most of the granules retained in the last day were 1.4 mm. The pigment analysis indicated the presence of the bacteriochlorophyll a implying the presence of anoxygenic photosynthetic bacteria. However, it is important to note that the molecular identification of the bacteria showed the presence of Enterobacter cloacae , Bacillus cereus and Lysinibacillus sp. which are typically known to be non-photosynthetic. These bacteria were found to possess photosynthetic pigments, mainly bacteriochlorophyll a and carotenoids.

River pollution from the agriculture industry has become an important cause of unscheduled water disruptions in Malaysia. Thus, rigorous control and treatment of high strength wastewater prior to discharge into the river are needed. This study aims at evaluating the performance of a pilot membrane bioreactor (MBR) for the treatment of palm oil mill effluent (POME). POME was subjected to MBR operating in an aerobic environment for 40 days, followed by 10 days without aeration and water pumping to simulate failure event, and finally resumed to operational condition. Higher proportions of protein (-PN) compared to polysaccharides (-PS) were present in both the mixed liquor and biofilm, indicating that protein was the main constituent of extracellular polymeric substances (EPS). Biological samples from the mixed liquor and biofilm on the membrane surfaces were collected on day 25, 50 and 75 to investigate taxonomic distribution of microbial community. High throughput sequencing of the 16S rRNA gene was used to investigate the composition of microbial communities in the MBR. Microbial groups such as the phyla Proteobacteria (19–23%), OD1 (11–15%), Chloroflexi (11–13%) were the dominant members in biofilm under operational condition while OD1 (20%), Proteobacteria (18%) and Planctomycetes (16%) were found to be dominant in biofilm under static and non-operational conditions. The taxonomic profile of the microbial community on day 75 is more similar to that of day 25, compared to day 50, suggesting the capability of the microbial communities to revert to the operational state despite a period of downtime.

Anoxybacillus sp. SK 3-4 is a Gram-positive, rod-shaped bacterium and a member of family Bacillaceae. We had previously reported that the strain is an aluminum resistant thermophilic bacterium. This is the first report to provide a detailed analysis of the global transcriptional response of Anoxybacillus when the cells were exposed to 600 mg L-1 of aluminum. The transcriptome was sequenced using Illumina MiSeq sequencer. Total of 708 genes were differentially expressed (fold change >2.00) with 316 genes were up-regulated while 347 genes were down-regulated, in comparing to control with no aluminum added in the culture. Based on Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, the majority of genes encoding for cell metabolism such as glycolysis, sulfur metabolism, cysteine and methionine metabolism were up-regulated; while most of the gene associated with tricarboxylic acid cycle (TCA cycle) and valine, leucine and isoleucine metabolism were down-regulated. In addition, a significant number of the genes encoding ABC transporters, metal ions transporters, and some stress response proteins were also differentially expressed following aluminum exposure. The findings provide further insight and help us to understand on the resistance of Anoxybacillus sp. SK 3-4 toward aluminium.

Amine-functionalized, silver-exchanged zeolite NaY (ZSA) were prepared with three different concentrations of 3-aminopropyltriethoxysilane (APTES) (0.01, 0.20 and 0.40 M) and four different concentrations of silver ions (25%, 50%, 100% and 200% from zeolite cation exchange capacity (CEC)). The samples were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX), surface area analysis, thermogravimetric analysis (TGA) and zeta potential (ZP) analysis. The FTIR results indicated that the zeolite was functionalized by APTES and that the intensity of the peaks corresponding to APTES increased as the concentration of APTES used was increased. The antibacterial activities of the silver-exchanged zeolite NaY (ZS) and ZSA were studied against Escherichia coli ATCC11229 and Staphylococcus aureus ATCC6538 using the disc diffusion technique (DDT) and minimum inhibitory concentration (MIC). The antibacterial activity of ZSA increased with the increase in APTES on ZS, and E. coli was more susceptible towards the sample compared to S. aureus. The FESEM micrographs of the bacteria after contact with the ZSA suggested different mechanisms of bacterial death for these two bacteria due to exposure to the studied sample. The functionalization of ZS with APTES improved the antibacterial activity of the silver-zeolite, depending on the concentration of silver ions and APTES used during modification.

Denitrification plays a significant role in both wastewater treatment and nitrogen cycle. But high amount of nitrate and accumulation of nitrite inhibit these processes. In view of this, a denitrifying phototrophic bacterium was isolated, characterized based on 16s rRNA analysis and its ability to remove toxic nitrogenous compounds investigated. Different initial concentrations were used to determine the effect of concentration on nitrogen removal and the biokinetic coefficients using Michaelis–Menten rate expression. The bacterium can remove 71% of nitrate at the initial concentration of 85 mg l−1 under photoheterotrophic growth condition without nitrite or ammonium accumulation. It can also remove 62% of ammonium at initial concentrations of 52 mg l−1 under anoxic growth condition without nitrate or nitrite accumulation. The results also showed that increase in concentrations led to decrease for both NO3− and NH4–N removal. Analysis and amplification of the possible genes that are involved in denitrification revealed the possession of napA and nirK genes. This strain can therefore serve as good candidate in wastewater treatment plants that are faced with the problem of nitrite accumulation and high amount of nitrogenous compounds that inhibit cell growth during biological nitrogen removal.

Lower temperature biohydrogen production has always been attractive, due to the lower energy requirements. However, the slow metabolic rate of psychrotolerant biohydrogen-producing bacteria is a common problem that affects their biohydrogen yield. This study reports on the improved substrate synthesis and biohydrogen productivity by the psychrotolerant Klebsiella sp. strain ABZ11, isolated from Antarctic seawater sample. The isolate was screened for biohydrogen production at 30°C, under facultative anaerobic condition. The isolate is able to ferment glucose, fructose and sucrose with biohydrogen production rate and yield of 0.8 mol/l/h and 3.8 mol/g, respectively at 10 g/l glucose concentration. It also showed 74% carbohydrate uptake and 95% oxygen uptake ability, and a wide growth temperature range with optimum at 37°C. Klebsiella sp. ABZ11 has a short biohydrogen production lag phase, fast substrate uptake and is able to tolerate the presence of oxygen in the culture medium. Thus, the isolate has a potential to be used for lower temperature biohydrogen production process.

A Gram-negative, arsenite-resistant psychrotolerant bacterial strain, Yersinia sp. strain SOM-12D3, was isolated from a biofilm sample collected from a lake at Svalbard in the Arctic area. To our knowledge, this is the first study on the ability of acid-treated and untreated, non-living biomass of strain SOM-12D3 to absorb arsenic. We conducted batch experiments at pH 7, with an initial As(III) concentration of 6.5 ppm, at 30 °C with 80 min of contact time. The Langmuir isotherm model fitted the equilibrium data better than Freundlich, and the sorption kinetics of As(III) biosorption followed the pseudo-second-order rate equation well for both types of non-living biomass. The highest biosorption capacity of the acid-treated biomass obtained by the Langmuir model was 159 mg/g. Further, a high recovery efficiency of 96% for As(III) was achieved using 0.1 M HCl within four cycles, which indicated high adsorption/desorption. Fourier transformed infrared (FTIR) demonstrated the involvement of hydroxyl, amide, and amine groups in As(III) biosorption. Field emission scanning electron microscopy–energy dispersive analysis (FESEM-EDAX) indicated the different morphological changes occurring in the cell after acid treatment and arsenic biosorption. Our results highlight the potential of using acid-treated non-living biomass of the psychrotolerant bacterium, Yersinia sp. Strain SOM-12D3 as a new biosorbent to remove As(III) from contaminated waters.

Lower temperature biohydrogen production has always been attractive, due to the lower energy requirements. However, the slow metabolic rate of psychrotolerant biohydrogen-producing bacteria is a common problem that affects their biohydrogen yield. This study reports on the improved substrate synthesis and biohydrogen productivity by the psychrotolerant Klebsiella sp. strain ABZ11, isolated from Antarctic seawater sample. The isolate was screened for biohydrogen production at 30°C, under facultative anaerobic condition. The isolate is able to ferment glucose, fructose and sucrose with biohydrogen production rate and yield of 0.8 mol/l/h and 3.8 mol/g, respectively at 10 g/l glucose concentration. It also showed 74% carbohydrate uptake and 95% oxygen uptake ability, and a wide growth temperature range with optimum at 37°C. Klebsiella sp. ABZ11 has a short biohydrogen production lag phase, fast substrate uptake and is able to tolerate the presence of oxygen in the culture medium. Thus, the isolate has a potential to be used for lower temperature biohydrogen production process.

Landfilling is most generally accepted disposal way for solid waste management due to low cost. However, landfilling will lead to production of turbid, odorous and dark brownish leachate wastewater. Leachate wastewater will carry different levels of biodegradable and non-biodegradable organic materials that will affect the leachate treatability, biodegradability and treatment method selection. In this study, biological treatment process is used together with physical adsorption method. 24% (w/v) of light weight aggregates is used as adsorbent for pollutants removal and further biological treatment with B. panacihumi strain ZB1 is used to polish the final effluent quality. As reported by previous study, sole biological treatment with B. panacihumi strain ZB1 able to remove nearly 40% of COD and 40% to 50% of ammonia nitrogen from leachate wastewater. In this research study, use of light weight aggregates together with B. panacihumi strain ZB1 for leachate treatment able to remove more than 70% of ammonia nitrogen from leachate wastewater. However, this combined treatment process does not show any significant effect on final COD level in leachate wastewater. Hence, other treatment method or optimization should be carried out to reduce the COD concentration in the leachate wastewater.

The discharge of highly coloured azo dyes effluent has caused serious environmental damages. In this study, bacteria isolated from Antarctica seawater were screened for their ability to decolourise azo dye Reactive Black 5 (RB5). The selected bacterium was further investigated to study its ability to decolourise RB5. The best bacteria from Antarctica seawater that had the ability to decolourise RB5 was identified using 16S rDNA sequence analysis and revealed that the bacteria 15C shared 99% homology to Klebsiella pneumoniae. Selection of the most effective bacteria was followed by its acclimatisation to decolourise higher concentrations of RB5 by growing it in successively higher concentrations of RB5. Following that, optimization of RB5 decolourisation by the selected bacteria was performed using one factor at time (OFAT) including concentration of dye, pH and temperature. The results obtained indicated the optimal condition for decolourisation of RB5 using this bacterium was at pH 10 and 37°C in 70 mg/L RB5 with 98% decolourisation within 24 h under facultative anaerobic treatment. Besides that, 70% of COD removal was achieved after 96 h of sequential anaerobic and aerobic treatment of RB5. In addition, FTIR and HPLC were used to analyze the metabolite of RB5 decolourisation. Products of RB5 decolourisation was confirmed by the presence of sulphanilic acid in HPLC analyses and the changes observed in the functional groups of the FTIR spectrum suggesting the possibility of RB5 degradation. Ammonia test and carbon dioxide test showed higher concentration of ammonia and carbon dioxide that indicates the mineralisation of product after treatment.

Background and objective A new green technology to reduce environmental damages while optimizing production of Pacific Whiteleg shrimp, Litopenaeus vannamei was developed known as "Biofloc technology". Microbial communities in biofloc aggregates are responsible in eliminating water exchange and producing microbial proteins that can be used as supplemented feed for L. vannamei. This study aimed to isolate and identify potential bioflocculant-producing bacteria to be used as inoculum for rapid formation of biofloc. Materials and methods For the purpose of this study, bacterial communities during 0, 30 and 70 days of culture (DOC) of L. vannamei grow-out ponds were isolated and identified through phenotypic and 16S rDNA sequences analysis. Phylogenetic relationships between isolated bacteria were then evaluated through phylogenetic tree analysis. One-way analysis of variance (ANOVA) was used to compare the differences of microbial communities at each DOC. Results Out of 125 bacterial isolates, nine species of bacteria from biofloc were identified successfully. Those bacteria species were identified as Halomonas venusta, H. aquamarina, Vibrio parahaemolyticus, Bacillus infantis, B. cereus, B. safensis, Providencia vermicola, Nitratireductor aquimarinus and Pseudoalteromonas sp., respectively. Through phylogenetic analysis, these isolates belong to Proteobacteria and Firmicutes families under the genera of Halomonas sp., Vibrio sp., Bacillus sp., Providencia sp., Nitratireductor sp. and Pseudoalteromonas sp. Conclusion In this study, bioflocculant-producing bacteria were successfully identified which are perfect candidates in forming biofloc to reduce water pollution towards a sustainable aquaculture industry. Presence of Halomonas sp. and Bacillus sp. in all stages of biofloc formation reinforces the need for new development regarding the ability of these species to be used as inoculum in forming biofloc rapidly.

Microbacterium sp. strain SZ1 isolated from gold ores of a Malaysia gold mine was found to be highly resistant to arsenic. Here, we report the draft genome sequence of SZ1, which may provide further insights into understanding its arsenic resistance mechanism. In this draft genome, a complete set of ars operons and two additional scattered ars genes were encoded.

In this paper, dissimilar joining of 316L stainless steel to low carbon steel was carried out using gas metal arc welding (GMAW) and gas tungsten arc welding (GTAW). Samples were welded using AWS: ER309L welding electrode for GMAW and AWS: ER316L welding electrode for GTAW process. Determination of mechanical properties and material characterization on the welded joints were carried out using the Instron tensile test machine and an optical microscope respectively. The cross section area of the welded joint consists of three main areas namely the base metal (BM), heat affected zone (HAZ), and weld metal (WM). It was found that, the yield and tensile strengths of welded samples using ER316L filler metal were slightly higher than the welded sample using ER309L welding electrode. All welded samples fractured at low carbon steel base metal indicating that the regions of ER316L stainless steel base metal, ER316L filler metal and heat affected zone (HAZ) have a higher strength than low carbon steel base metal. It was also found that ER316L welding electrode was the best filler to be used for welding two dissimilar metals between carbon and stainless steel.

The antibacterial activity of functionalized zeolite NaY (CBV100) with different concentrations of 3-aminopropyltriethoxysilane (APTES) (0.01, 0.05, 0.20 and 0.40 M) was studied against Staphylococcus aureus ATCC 6538 (Gram positive) and Escherichia coli ATCC 11229 (Gram negative) through disc diffusion technique (DDT). The characterization of functionalized zeolite NaY with fourier transform infrared (FTIR) spectroscopy indicated the attachment of APTES on zeolite NaY. Through DDT, the inhibition zone of functionalized zeolite NaY increased proportionally to the amount of the amine-functional group attached onto zeolite NaY. Functionalized zeolite NaY showed higher antibacterial activity against Gram-positive compared to Gram-negative bacteria. It can be concluded from this study that amine-functionalized zeolite NaY shows evidence of antibacterial activities.

Extensive use of recalcitrant azo dyes in textile and paper industries poses a direct threat to the environment due to the carcinogenicity of their degradation products. The aim of this study was to investigate the efficiency of Curvularia clavata NZ2 in decolorization of azo dyes. The ability of the fungus to decolorize azo dyes can be evaluated as an important outcome as existing effluent treatment is unable to remove the dyes effectively. C. clavata has the ability to decolorize Reactive Black 5 (RB5), Acid Orange 7 (AO7), and Congo Red azo dyes, utilizing these as sole sources of carbon and nitrogen. Ultraviolet-visible (UV-vis) spectroscopy and Fourier infrared spectroscopy (FTIR) analysis of the extracted RB5's metabolites along with desorption tests confirmed that the decolorization process occurred due to degradation and not merely by adsorption. Enzyme activities of extracellular enzymes such as carboxymethylcellulase (CMCase), xylanase, laccase, and manganese peroxidase (MnP) were also detected during the decolorization process. Toxicity expressed as inhibition of germination was reduced significantly in fungal-treated azo dye solution when compared with the control. The cultivation of C. clavata under sequential batch system also recorded a decolorization efficiency of above 90%. The crude enzyme secreted by C. clavata also showed excellent ability to decolorize RB5 solutions with concentrations of 100 ppm (88-92%) and 1000 ppm (70-77%) without redox mediator. This proved that extracellular enzymes produced by C. clavata played a major role in decolorization of RB5.

Production of crude palm oil generates a huge amount of palm oil mill effluent (POME) and oil palm empty fruit bunch (OPEFB), leading to adverse environmental impacts. This study seeks to explore the ability of Curvularia clavata in the utilization of such waste to produce lignocellulolytic enzymes such as carboxymethyl cellulase, xylanase, manganese peroxidase, laccase and lignin peroxidase. Raw POME generated from the milling process is discharged to the raw pond, followed by generation of anaerobic POME that is an intermediate step in treatment process. Utilization of raw POME produces higher enzyme activities compared to anaerobic POME. This simultaneously resulted in detoxification and significant removal of COD (67 %), BOD3 (45 %), total polyphenolic (50 %) and ammoniacal nitrogen (61 %) of POME. Under submerged fermentation of OPEFB, C. clavata produces 3569 U/mL of xylanase, which has a potential application in the production of xylanase.

The Anoxybacillus sp. SK 3-4, previously isolated from a hot spring, was screened for its heavy metals resistance (Al(3+), Mn(2+), Cu(2+), Co(2+), Zn(2+), and Ni(2+)) and the strain was found to be most resistant to aluminum. Significant growth of the strain was observed when it was grown in medium containing aluminum (200 mg L(-1)-800 mg L(-1)) with relative growth rates ranging between 77% and 100%. A gene encoding the aluminum resistance protein (accession number: WP_021095658.1) was found in genome of strain SK 3-4, which revealed high sequence identity (>95%) to its homologues from Anoxybacillus species. Sequence comparisons with two functionally characterized aluminum resistance proteins, namely G2alt and ALU1-P, showed 97% and 81% of sequence identity, respectively. Four putative metal binding sites were detected in SK 3-4 aluminum resistance protein and G2alt at same amino acid residue positions of 186, 195, 198, and 201. Strain SK 3-4 was found to be able to remove aluminum from aqueous solution. This study demonstrated that Anoxybacillus sp. SK 3-4 could be applied in the treatment of aluminum contaminated wastewater.

The processing of palm oil generates highly polluting effluent called palm oil mill effluent (POME). Due to the inefficiency of conventional treatment methods to meet the environmental standard discharge limit, alternative treatment methods could play a positive role in treating POME. In this study, biofilm-coated macrocomposites were used to treat the POME obtained from palm oil industry. Color and chemical oxygen demand (COD) removal were the main parameters analyzed in this study. The rate of color removal was examined using the Elovich equation, Pseudo-first-order, and Pseudo-second-order kinetics models. Pseudo-first-order gave the best model equation for color adsorption of POME. The biofilm that was coated on the macrocomposites consisted of a mixed bacterial culture of Brevibacillus panacihumi, Enterococcus faecalis, Lysinibacillus fusiformis, and the newly identified Klebsiella pneumonia (MABZ). All of these bacteria were previously confirmed as bacteria capable of removing color and COD....