Production of lipopeptide biosurfactant by Kurthia gibsonii KH2 and their synergistic action in biodecolourisation of textile wastewater

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

Decolorization of Remazol Briliant Blue R by Laccase from White Rot Fungus Polyporus sp. S133

The decolourization of the recalcitrant dye RBBR by the culture filtrate of Polyporus sp. S133 and its isolatedlaccase was investigated. The laccase alone decolorized RBBR. A small molecular weight redox mediator (HBT) wasnecessary to increase the decolorization. The purified laccase totally decolorized the dye of 200 mg l-1 initialconcentration of RBBR when only 1.5 U ml-1 of laccase was used in the reaction mixture. The effects of differentphysicochemical parameters were tested and optimal decolorization rates occurred at pH 5 and at a temperature of 50°C. The effect of surfactants on the decolourization of RBBR was tested with Tween 80, Tween 20, and Brij 35. It wasdemonstrated that Tween 80 was inhibiting substrate for the decolorization while Tween 80 and Brij 35 was noinhibiting effect for the decolorization. Provided that all of the condition is included, it is suggested that laccase maybe suitable for the wastewater treatment of similar anthraquinone dyes.Keywords: Decolorization; Laccase; Remazol Brilliant Blue R (RBBR); Polyporus sp. S13

Identification of Metabolic Intermediates in Microbial Degradation of Chrysene by Armillaria sp. F022

To degrade chrysene, a polycyclic aromatic hydrocarbon (PAH), Armillaria sp. F022, a fungus collected from a soil, was used. Maximal degradation (77%) was obtained when Armillaria sp. F022 was incubated in cultures agitated at 120 rpm for 30 days, as compared to just 41% degradation in stationary culture. Furthermore, the degradation of chrysene was affected by the addition of surfactants. The mechanism of degradation was determined through identification of the intermediates. Several enzymes (manganese peroxidase, lignin peroxidase, laccase, 1,2-dioxygenase and 2,3-dioxygenase) produced by Armillaria sp. F022 were detected in the culture. The highest level of activity was shown by 1,2-dioxyg~ase after 20 days (143.6U 1.1).These ligninolytic and dioxygenase enzymes played an important role in the oxidation of chrysene. Chrysene was indeed degraded by Armillaria sp. F022 through several intermediates, chrysenequinone, 2-((IE,3E)-4-carboxy-3-hydroxybuta-l,3-dien-l-yl)-I-naphthoic acid, I-hydroxy-2- naphthoic acid, and gentisic acid

Seagrass Meadows under the Changing Climate: A Review of the Impacts of Climate Stressors

Seagrass meadows provide important ecological functions, particularly by serving as carbon sinks and breeding grounds for marine species. Climate change has threatened seagrass communities, causing their replacement, loss and increased vulnerability. This review examined scholarly articles published between 2010-2021 to comprehensively present the impacts of climate change on seagrass meadows. It shows that ocean warming negatively affects seagrass communities by favouring communities of lower structuring capacities, thus reducing the effectiveness of their ecological functions. Ocean warming also promotes the propagation and spread of invasive species, and changes the trophic structures leading to further loss of seagrasses of value. Higher seawater temperature is associated with shoot mortality and retarded growth of certain seagrasses. Sea level rise causes more wave energy to be received by coastal seagrass communities, thus, creating more damage to the communities. Deepening sea limits light penetration and alters distribution of seagrass meadows. Carbon dioxide enrichment of seawater increases photosynthetic rate of seagrasses but ocean warming and acidification counteract this beneficial effect. Carbon dioxide enrichment affects different seagrass species and different parts of a seagrass species differently, and, where beneficial to seagrass communities, could enhance their ecological services. Temperature extremes could kill seagrasses while marine heatwaves and flooding could act synergistically to increase carbon demand of certain seagrasses and unfavourably change their biomass. These impacts are often aggravated by anthropogenic activities. This review calls for more studies and conservation efforts to understand the impacts of climate change on seagrass communities and future-proof them against the changing climate

Adsorption of Basic Dyes Crystal Violet on Agricultural Biomass: Characterization, Isotherm, and Kinetic Studies

The removal of crystal violet (CV) dye from aqueous solution using agricultural waste-based adsorbent was investigated. Two adsorbents, lime peels (Citrus aurantifolia) and pineapple leaves (Ananas comosus) at different quantities (1, 3, 5, 7 and 10 g) were tested to 50 mL of CV solution (1,000 mg/L) at 3-hours interval incubation. The characterization of adsorbents was performed by FESEM and FTIR to explain adsorbent’s properties and structure. The results showed that lime peels and pineapple leaves removed 98% and 97% of CV dye, respectively. Under FESEM analysis, the surface structure of adsorbent that perforated and the presence of polymer were attributable to the adsorption ability. Indeed, FTIR analysis confirmed the attendance of carboxyl and carbonyl group that caused the enhancement of adsorption process. Keywords: crystal violet, basic dye removal, agricultural based-adsorben

Identification of Metabolic Intermediates in Microbial Degradation of Chrysene by Armillaria sp. F022

To degrade chrysene, a polycyclic aromatic hydrocarbon (PAH), Armillaria sp. F022, a fungus collected from a soil, was used. Maximal degradation (77%) was obtained when Armillaria sp. F022 was incubated in cultures agitated at 120 rpm for 30 days, as compared to just 41% degradation in stationary culture. Furthermore, the degradation of chrysene was affected by the addition of surfactants. The mechanism of degradation was determined through identification of the intermediates. Several enzymes (manganese peroxidase, lignin peroxidase, laccase, 1,2-dioxygenase and 2,3-dioxygenase) produced by Armillaria sp. F022 were detected in the culture. The highest level of activity was shown by 1,2-dioxygenase after 20 days (143.6 U l-1). These ligninolytic and dioxygenase enzymes played an important role in the oxidation of chrysene. Chrysene was indeed degraded by Armillaria sp. F022 through several intermediates, chrysenequinone, 2-((1E,3E)-4-carboxy-3-hydroxybuta-1,3-dien-1-yl)-1-naphthoic acid , 1-hydroxy-2-naphthoic acid, and gentisic acid. Keywords : Biodegradation, Chrysene, Metabolites, Armillaria sp. F02

Bioremediation of Diesel Oil Spill by Filamentous Fungus Trichoderma reesei H002 in Aquatic Environment

Bioremediation of aquatic environment could be a response to the oil spills threats. In this paper, Trichoderma reesei H002, a filamentous ascomycete fungus isolated from a polluted site in an orchard garden, Johor, Malaysia, was experimented for its biodegradation ability to degrade diesel oil. Varying nitrogen and carbon sources, pH, agitation on diesel oil by Trichoderma reesei H002 in liquid media were examined to find their impacts on TPHs, alkane, aromatic and NSO fractions of diesel oil degradation. Glucose and yeast extract were the most suitable nutrients for the development of T. reesei H002 and increased the degradation of total petroleum hydrocarbons (TPHs up to 94.78% at the end of the study (40 days) at 25 0C. The degradation of TPHs were performed by gravimetric analysis and degradation of alkane and aromatic fractions were confirmed by GC-FID analysis. Based on the findings of T. reesei H002 for the biodegradation of diesel oil, it can be proposed that T. reesei H002 can be applied to bioremediate diesel oil spill in aquatic environment, therefore protect the ecosystem

Challenges and Solutions for Sustainable Groundwater Usage: Pollution Control and Integrated Management

Purpose of Review This paper aims to critically reviewthe current status of groundwater usage fromthe point of viewof pollutant control and integrated management. Recent Findings This paper has shown that sustainable efforts must be encouraged to minimize the arsenic content from all the possible sources before entering the groundwater system. Excessive nitrate and pesticide utilization must be significantly reduced for a sustainable environment. Although various in situ remediation technologies are possible to remove some contaminants in the groundwater, the future concern is how it can be carried out in accordance with environmental sustainable goal such as the implementation of in situ bioremediation and bioelectroremediation which provide a cheaper and greener solution compared to physical and chemical approaches. To develop a successful integrated management for a sustainable groundwater usage in the future, conjunctive water management is recommended as it involves the management of ground and surface water resources to enhance security of water supply and environmental sustainability. Summary This paper critically reviews the current state of knowledge concerning groundwater usage from the point of view of pollutant control and integrated management. Information presented in this paper is highly useful for the management of groundwater not only in the quality point of view but also in the sustainable quantity for future development