An Investigation into the Suitability of Sulfate-Reducing Bacteria as Models for Martian Forward Contamination

The NASA Planetary Protection policy requires interplanetary space missions do not compromise the target body for a current or future scientific investigation and do not pose an unacceptable risk to Earth, including biologic materials. Robotic missions to Mars pose a risk to planetary protection in the forms of forward and reverse contamination. To reduce these risks, a firm understanding of microbial response to Mars conditions is required. Sulfate-reducing bacteria are prime candidates for potential forward contamination on Mars. Understanding the potential for forward-contamination of sulfate-reducers on Mars calls for the characterization of sulfate-reducers under Mars atmosphere, temperature, and sulfate-brines. This study investigated the response of several sulfate-reducing bacteria, including spore formers and psychrophiles. The psychrophile Desulfotalea psychrophila was found to inconsistently survive positive control lab conditions, attributed to an issue shipping pure cultures. Desulfotomaculum arcticum, a spore-forming mesophilic sulfate-reducer, and Desulfuromusa ferrireducens, an iron and sulfate-reducer, were metabolically active under positive control lab conditions with complex and minimal growth medium. A wastewater treatment sulfate-reducing bacteria (SRB) isolate was subjected to sulfate + growth-medium solutions of varied concentrations (0.44 & 0.55% wt. SO42-). The wastewater SRB displayed higher cellular light-absorbance levels at delayed rates in 0.55% sulfate solutions, suggesting a greater total culture reproduction, but with increased lag time. Additional SRB were isolated from marine sediments, subjected to a shock pressure of 8.73 GPa, and returned to ideal conditions. The sulfate-concentration patterns in the impacted SRB culture suggests a destruction of culture occurred somewhere during the preparation process. The response of SRB in this investigation to Ca and Na sulfate-brines suggests that Martian sulfate deposits offer a viable energy sink to terrestrial microorganisms, and the studied SRB are capable of replication at reduced water-activity. Further investigation (i.e. sulfate cations and concentrations, temperature, pressure, etc.) may identify Martian locations at risk to forward contamination

Biodegradation of textile dye effluent through Indigenous bacteria

The textile industry is considered as one of the major generators of toxic chemical wastewater in India. Dyes released by the textile industries pose a threat to environmental safety. Dye decolorization through biological means has gained momentum as these are cheap and can be applied to a wide range of dyes. The present study concentrates in the isolation, identification of indigenous bacteria namely D1, D2, D3 and D4 from textile dye effluent collected from the local textile dyeing shop located at Gurahakuan, Banda district, Uttar Pradesh, India, and evaluation of their ability to decolorize dyes sample. The isolated bacteria were identified through morphological and biochemical characteristics. Scanning electron microscope (SEM) analysis of isolated bacteria showed that all the bacteria appeared rod-shaped with size ranging from 1.33 to 2.84 µm. The physico-chemical analysis of dye effluent indicated the bluish-black color of the effluent having pH of about 8. The Biological Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) value of the raw sample was estimated to be 470 mg/l and 800 mg/l, respectively, for dye effluent sample. The value of Total Dissolved Solids (TDS) and Total Suspended Solids (TSS) was estimated to be 1760 mg/l and 560 mg/l, respectively, in our dye effluent sample. The study aims to isolate and optimize four bacterial isolates having the ability to degrade and decolorize azo dyes produced in the final dying effluent. The optimization results revealed that all the bacteria showed maximum growth at pH 8, temperature 35°C and declines further. All the isolated bacterial species showed significant potential for dye decolorization and degradation at varying wavelengths such as 420, 480, 506, 520, 620 and 668 nm but maximum removal of color (about 88%) was obtained at 668 nm after 48h by bacterial isolate D3. Thus, these selected native bacteria can be employed as a vital biological tool for developing decentralized wastewater treatment systems for decolorization of dye effluents through biosorption or biodegradation which is a cost-effective process

Nickel-Iron Alloy Nanoparticle Characteristics Pre- and Post-Reaction With Orange G

Bimetallic nanoparticles comprised of iron and nickel were synthesized, characterized, and evaluated to optimize the ideal metal ratio for azo dye removal from water systems. Results show that changing the molar ratio of nickel to iron caused different removal rates, as well as the extent of overall elimination of azo dye from water. Lower molar ratios, from Ni1Fe10 to Ni2.5Fe10, exhibited a higher removal efficiency of 80–99%. Higher concentrations of Ni in the catalyst, from Ni3Fe10 to Ni5Fe10 , resulted in 70–90% removal. The lower molar ratios of Ni exhibited a consistent removal rate of 0.11 g/L/min, while the higher molar ratios of Ni displayed varying removal rates of 0.1–0.05 g/L/min. A second order kinetic model was fit to the first twenty minutes of the reaction for all nickel to iron compositions, where there is a decrease in rate constant with an increase in molar ratio. During the last forty minutes of reaction, azo dye removal fit a zero order kinetic model. All as-synthesized nanoparticle samples were found to be structurally disordered based on the lack of distinct peaks in XRD spectra. Post-reaction samples were found to have Fe2O3 and FeOOH cubic peaks

Identification and evaluation of locally isolated fungi through rapid screening for potential mycelium-based biofoam application in Malaysia

Expanded polystyrene foam (EPS) contributes to environmental problems due to its inability to decompose in nature within a short period. In addition, petroleum as a core source for EPS is now depleting and new biological and environmentally friendly approaches are encouraged. As an alternative to EPS, mycelium-based biofoam (MBF) is a new foam technology formed of agricultural biomass and mycelium as a binding matrix is introduced. However, based on previous literature, the fungal strains used are mainly highlighted as one of the main factors which affect the final properties of MBF. Thus, this study aims to evaluate the most potential fungus used for MBF application using OPEFB, biomass from the palm oil industry as novel substrate using rapid screening. Twelve local fungi isolated from a local forest in Selangor, Malaysia were cultivated on Potato Dextrose Agar and OPEFB plate before being screened on agar containing four different types of dye indicators, which are methylene blue, guaiacol, Remazol Brilliant Blue R and azure B. As a result, Phanerochaete concrescens isolate LYN-UPM S1 and Perenniporia subtephropora isolate LYN-UPM S9 have shown the ability to produce ligninolytic enzymes and high content of chitin, which will be useful for the fabrication of mycelium-based biofoam

Microbial degradation of Organopolutants

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