Environment and Natural Resources Journal

Mycoremediation Potential of Synthetic Textile Dyes by Aspergillus niger via Biosorption and Enzymatic Degradation

Manavi Sulakkana Ekanayake — 2022-04-05

Textile dyes that persist in the environment are highly resistant to the natural degradation processes that occur in the environment. Therefore, the present study isolated, identified, and optimized textile dye decolorization by fungi and elucidated the dye decolorization pathway to develop a low-cost biotechnological approach for decolorization and detoxification of textile dyes. Within 36 hours of incubation at temperatures ranging from 28 to 40°C, pH 7, and shaking at 100 rpm, Aspergillus niger MN990895, which was selected from a total of 77 fungal isolates, completely decolorized the model dye CI Direct Blue 201 (DB 201). A. niger biosorbed 8.4±1.2% of the dye used where live biomass showed complete dye removal. It was found that extracellular crude enzymes were more involved in DB 201 dye decolorization (72.7±3.3%) than intracellular crude enzymes. The enzymatic studies suggested that the primary enzyme involved in DB 201 textile dye decolorization was lacccase, which was further confirmed by the presence of distinct protein bands around 75-100 kDa on the SDS-PAGE. The FTIR spectra and seed germination assays confirmed that A. niger proved successful in DB 201 textile dye degradation and detoxification. The present study suggests that A. niger may have promising implications in the future for the development of an enzyme-based textile wastewater treatment system.

Social Life Cycle Assessment of Green and Burnt Manual Sugarcane Harvesting in the Northeastern Thailand

Thiwaporn Thuayjan — 2022-04-05

Despite green sugarcane harvesting being promoted in Thailand, with some limitations on the use of harvesting machines, green sugarcane harvesting is practiced manually in many sugarcane fields. Although the environmental benefit seems clear, this harvesting practice’s social implications are yet unknown. This study assessed social performances of green and burnt manual sugarcane harvesting in North-Eastern Thailand, the region hosting the largest sugarcane plantation area, using the Social Life Cycle Assessment technique. Data collection was undertaken by surveys. The performance reference points method was applied to assess the different stakeholder’s social performances. Key stakeholder groups examined were workers, local community, and farm owners. The main social issues included in this study are fair wages, working conditions, health and safety, local employment, economic development, social responsibility, and satisfaction of occupation. The results showed that the social performances of green and burnt sugarcane harvesting were generally similar except for the local community group. This is mainly due to the health impact of sugarcane burning on the local community. Different issues cause the farmers to harvest the burnt sugarcane; for example, labor shortage in the harvesting season and the difficult working conditions for green harvesting, causing the farm owners to bear higher costs. For these reasons, mechanized harvesting is suggested to help promote green harvesting to reduce local air pollution. However, technology development is in urgent need to make the harvesting machines more affordable and applicable to all geographical conditions.

Plant Growth Promoting Activities of Spore-Forming and Vegetative Cells of Salt-Tolerant Rhizobacteria under Salinity Condition

Tiptida Kidtook — 2022-04-05

Plant growth promoting rhizobacteria are able to enhance plant growth. This study isolated spore-forming rhizobacteria from vegetable rhizosphere soil samples. These isolates were tested for their abilities to promote plant growth and to be used in bio-fertilizers. Thirty-nine isolates with different characteristics were obtained. Three isolates, TYS1.1, TYS3.3, and TYS3.5, showed multifunctional activities on nitrogen fixation and potassium solubilization. They were tested for IAA production in liquid medium supplemented with tryptophan and NaCl, with the vegetative cells of isolate TYS3.5 showing the highest IAA production. The colonization of the three isolates on okra roots was checked by spread plate technique and scanning electron microscope. It was found that rhizobacteria could colonize plant roots with a concentration of 8.19 log CFU/g in the presence of 50 mM NaCl solution. Bio-fertilizer was produced by immobilizing the mixture of three isolates on carriers. The viable cells were enumerated during the storage at room temperature for 60 days. The results showed that the highest number of survival cells in the form of vegetative and spore-forming cells were obtained when using rice husk ash and vermiculite as a carrier. The concentration of viable cells was in a range of 8.14-8.44 log CFU/g. These isolates were Bacillus sp. according to the 16S rDNA sequencing analysis.

Use of Bayesian, Lasso Binary Quantile Regression to Identify Suitable Habitat for Tiger Prey Species in Thap Lan National Park, Eastern Thailand

Paanwaris Paansri — 2022-04-05

A Bayesian approach was used to develop binary quantile regression models featuring the lasso penalty. The models afford the advantages of all quantile regression models, such as robustness and detailed insights into covariate effects; they also handle issues associated with overfitting well. Thus, this model was used to investigate habitat suitability for the management of tiger prey species. Field data were collected from 150 sampling sites (2,416 sub-plots) in Thap Lan National Park of the Dong Phayayen-Khao Yai Forest Complex (DPKY) from August 2019 to March 2021. We focused on sambar deer (Rusa unicolor) and gaur (Bos gaurus) because they are the principal prey species of tigers. Vegetation was sampled for biomass and nutrient content to identify suitable habitat. The “bayesQR” package of R was used to identify habitats appropriate for these species. The correlation between forage crop biomass and the normalized difference vegetation index (NDVI) was significantly associated with tiger prey species presence. The habitat can be improved by increasing grass and forb biomasses as the prey species prefer open habitats, such as grassland and open areas of dry evergreen forest. Habitat management has ensured that the grass biomass of open forest is significantly higher than that of dense forest. In addition, the hemicellulose content of open forest was significantly greater than that of dense forest. We found that spatial modeling combined with Bayesian, lasso binary quantile regression could aid wildlife habitat management in a Thai National Park.

Environmental Factors Modulating Indole-3-Acetic Acid Biosynthesis by Four Nitrogen Fixing Bacteria in a Liquid Culture Medium

Le Thi Xa — 2022-04-05

This study evaluated the effects of some environmental conditions on IAA biosynthesizing capacity of four nitrogen fixing bacteria, namely Paenibacillus cineris TP-1.4, Bacillus megaterium MQ-2.5, Klebsiella pneumoniae OM-17.2, and Pseudomonas boreopolis CP-18.2. Carbon source, pH, NaCl, and tryptophan supplement treatments were set to investigate the effects of those environmental factors on IAA synthesis. The IAA synthesizing capacity of bacterial strains in liquid medium was measured spectroscopically following incubation by Salkowski's reagent method. The results showed that, under the sucrose amendment, the IAA concentrations produced by all four bacterial strains were significantly higher than those of the other four carbon source added treatments. Two of the four bacterial strains produced the highest yield of IAA in liquid medium at pH 7 (TP-1.4 and OM-17.2), whereas pH 8 was optimum for the other two strains (MQ-2.5 and CP-18.2). The MQ-2.5 strain could synthesize IAA fairly well in up to 5% NaCl and produced the highest amount of IAA with 1% NaCl. Furthermore, IAA synthesizing capability of tested bacterial strains increased sharply along with increasing tryptophan content in culture medium except for the TP-1.4 strain. From the current study, these isolates emerged as possible alternatives for future IAA production for plant growth and yield enhancement. Hence, they have a great potential to be used as bio-inoculants for plant growth promotion in eco-friendly and sustainable agriculture.

Adaptiveness to Enhance the Sustainability of Freshwater-Aquaculture Farmers to the Environmental Changes

Anawach Saithong — 2022-04-05

Two alternative physical adaptations of freshwater-aquaculture farmers were observed along the upstream Bangpakong Watershed, Thailand. First was the modification of aquaculture types: (1) completely changing former species to others; (2) mixing freshwater prawn with current cultured species; (3) mixing fish with L. vannamei, and second was the direct reaction to environmental changes, including adding freshwater into cultured ponds to reduce temperature and dilute salt concentration; modifying pond-depth; aeration application; and reducing the amount of food or net covering on the water surface during flooding. Principal component analysis revealed that four key components (Options, Learning, Competitiveness, and Plan) reflected the perceived adaptive capacity of farmers to environmental changes. However, culture types have no significant effect on these four components. Farmers with an alternative source of income and practicing monoculture fish farming tend to have a greater ability to change occupation. Old age and more extended experience in aquaculture indicated a low ability to change occupation. The well-educated farmers and farmers who preferred to pass on aquaculture occupation to their children showed higher ability to learn and adapt, but this is not the case for older farmers. Thus, understanding the adaptations of the farmers may assist in promoting appropriate development programs based on their contexts as well as helping decision-makers to have a better plan for strengthening their adaptive capacities based on their perceptions.

Water Turbidity Determination by a Satellite Imagery-Based Mathematical Equation for the Chao Phraya River

Wilaiporn Pimwiset — 2022-04-05

Turbidity is a standard water quality parameter that indicates its optical property in scattering light along the column containing suspended particles. The satellite imagery information of Sentinel-2 and the Chao Phraya River turbidity data from December 2016 to February 2021 was applied to develop a mathematical equation for turbidity determination. This practical and straightforward approach eliminates some constraints of traditional laboratory analysis, which is labour-intensive and time-consuming in monitoring the entire river. Four studied steps were implemented: data pre-processing, correlating analysis of numerical turbidity and satellite image reflectance, developing the mathematic equations for turbidity estimation, and its validation of use. Four different bands (B2, B3, B4, and B8) and three selection methods were investigated; single-band, combination band, and ratio band. The obtained results depicted that the reflectance of B4 in the single-band process promoted the highest correlation with turbidity compared to the others. The reflectance in visible wavelengths increased when the turbidity of river water increased, particularly B4. The mathematical power equation was a more suitable function for evaluating turbidity than linear regression, quadratic, and exponential functions. A similar concentration was obtained for measured and estimated turbidity in the validation. This finding demonstrated the potential application of remotely sensed data to estimate river water turbidity with high capability and accuracy that adequately supports spatial data continuity acquisition.

Dynamic Occupancy of Wild Asian Elephant: A Case Study Based On the SMART Database from the Western Forest Complex in Thailand

Peerawit Amorntiyangkul — 2022-04-05

Understanding distribution patterns is essential for the long-term conservation of megafauna, particularly the Asian elephant (Elephas maximus). We investigated the dynamic occupancy of Asian elephants in the Thung Yai Naresuan West Wildlife Sanctuary in Thailand. Asian elephant occurrences were recorded during patrol activities from 2012 to 2019. We applied a single-species dynamic occupancy model to examine the environmental factors influencing habitat occupancy of Asian elephant across multiple seasons. The best-supported model, based on the Akaike information criterion (AIC), indicated that the normalized difference vegetation index and elevation positively influenced the probability of colonization. In contrast, the distance to the nearest population source sites showed a negative association. The probability of local extinction was positively correlated with the distance to the nearest villages and population source sites. The predictive map indicated a higher probability of colonization in a remote mountainous region of the center of the protected area. Higher extinction probability was associated with areas of dense human activity and far from population source sites connecting the Asian elephant population to the east. This is the first study to utilize a patrol database for assessing the dynamic occupancy of Asian elephants across multiple years. Our model provides insight into the dynamic distribution patterns of Asian elephants within the wildlife sanctuary and the factors that most influence these patterns. Long-term ecological data provide crucial information for assessing biodiversity, population status, and the ecological processes of focal wildlife species and are valuable for both protected area management and conservation efforts.

Synthesis of Hydroxyapatite/Zinc Oxide Nanoparticles from Fish Scales for the Removal of Hydrogen Sulfide

Dan-Thuy Van-Pham — 2022-04-05

The presence of hydrogen sulfide (H₂S) is an issue for industrial processing, such as gasoline, natural gas, and biogas. In this study, hydroxyapatite (HA) nanoparticles with high purity were successfully extracted from red tilapia fish scales and used as supporting materials for zinc oxide (ZnO) to remove H₂S. Various amounts of ZnO decorated on HA nanoparticles were prepared from a zinc nitrate hexahydrate precursor. Powder X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) of the ZnO/HA samples demonstrated the successful synthesis of ZnO/HA with high purity. The scanning electron microscope (SEM) image analysis confirmed the uniform deposition of ZnO on HA nanoparticles which were smaller than 245 nm. The ZnO/HA samples with different ZnO loadings (i.e., 5, 10, and 15 wt%) were used to remove H₂S at room temperature. The specific surface area of HA and ZnO/HA determined by the Brunauer-Emmett-Teller (BET) method was 37.022 (m²/g) and 111.609 (m²/g), respectively. The experimental results demonstrated the highest breakthrough sulfur capacity of 26.3 mg S/g with the sorbent ZnO (15 wt%)/HA nanoparticles. This H₂S adsorption capacity was the highest capacity ever achieved for ZnO/HA.Therefore, there are great possibilities for effective removal of H₂S at the ambient conditions using the ZnO (15 wt%)/HA nanoparticles, where HA nanoparticles could be sustainably extracted from the abundant organic source of red tilapia fish scales.

Evaluation of Spontaneous DNA Damage Using the Alkaline Comet Assay in Lymphocyte Cells of Humans Living in the High Level Natural Radiation Area of Mamuju, Indonesia

Darlina Darlina — 2022-04-05

To evaluate the biological impacts of high background radiation exposures that are represented by spontaneous deoxyribonucleic acid (DNA) damage, an evaluation on lymphocyte cells from residents of Mamuju, West Sulawesi, Indonesia was tested. The mean annual dose received by individuals in this area is about 10.40 mSv. Of the 177 adult subjects studied, 102 were from high-level natural radiation areas of Mamuju and 75 subjects were from a nearby normal-level natural radiation area. Both areas are similar in living situations. DNA strand breaks and other parameters of study and control group were determined using a standardized comet assay. Our results showed that chronic low-level natural radiation had resulted in significantly higher (p<0.001) DNA damage based on the three parameters of the assay (tail length, tail DNA, and tail moment) compared to those of control. There was a positive correlation between the level of DNA damage and age, where people aged 40 years and older had a higher level of DNA damage than those under 40 year. The level of DNA damage was also found to be higher in females compared to that of males. It was concluded that chronic exposure to natural radiation in Mamuju had induced spontaneous DNA damage in human cells after long-term exposure which was dependent on age and sex.