Characterizations of highly efficient moderately halophilic toluene degrading M7 strain isolated from Egyptian saline sediments
Toluene and other monoaromatic compounds are released into the environment particularly saline habitats due to the inappropriate disposal methods of petroleum products. Studying the bio-removal strategy is required to clean up these hazardous hydrocarbons that threaten all ecosystem life using halophilic bacteria with higher biodegradation efficiency of monoaromatic compounds as a sole carbon and energy source. Therefore, sixteen pure halophilic bacterial isolates were obtained from saline soil of Wadi An Natrun, Egypt, which have the ability to degrade toluene and consume it as the only source of carbon and energy. Amongst these isolates, isolate M7 exhibited the best growth with considerable properties. This isolate was selected as the most potent strain and identified based on phenotypic and genotypic characterizations. The strain M7 was belonging to genus and founded to be closely matched to the with a similarity of 99%. Using toluene as sole carbon source, strain M7 showed good growth at a wide range temperature degree (20-40ºC), pH (5-9), and salt concentrations (2.5-10%, ) with optimal growth conditions at 35ºC, pH 8, and 5%, respectively. The biodegradation ratio of toluene was estimated at above optimal conditions and analyzed using Purge-Trap GC-MS. The results showed that strain M7 has the potentiality to degraded 88.32% of toluene within greatly short time (48 h). The current study findings support the potential ability to use strain M7 as a biotechnological tool in many applications such as effluent treatment and toluene waste management.
Emerging and innovative technologies for water and wastewater treatment
A comprehensive review on nanobiotechnology for bioremediation of heavy metals from wastewater
Removal of contaminants from wastewater is a big concern for the scientific community. Heavy metals are one of the major contaminants present in wastewater. Heavy metals such as Cd , Pb , Mn , and so forth, are highly toxic and pose a serious threat to the environment due to their nonbiodegradable nature. With the advent of nanobiotechnology, heavy metal contaminants can be mitigated with the help of nanomaterials produced by eco-friendly methods. Specially designed bionanomaterials often exhibit properties such as increased shelf life, self-healing nature, adaptability in different environments, and cost-effectiveness, thus showing advantages over nanomaterials produced by physicochemical methods. Due to their high specificity and adsorption capacity, bionanomaterials can remove heavy metals present even in a very low concentration in wastewater. The use of bionanotechnology in their remediation paves a way for environmental sustainability and helps in cost reduction. This paper intends to discuss the nanobiotechnological approach for the remediation of heavy metals from wastewater. Furthermore, the paper also reviews some important nanomaterials and their potential applications in the depollution of heavy-metal contaminated wastewater.
Special issue: Emerging microbial technologies for wastewater treatment
Bioprospecting plant growth-promoting rhizobacteria from rice genotypes and their influence on growth under aerobic conditions
The bacteria that colonize plant roots and enhance plant growth by various mechanisms are known as plant growth-promoting rhizobacteria (PGPR). The functions of rhizobacteria stand substantially unexplored and detailed insights into the aerobic rice ecosystem are yet to be examined. In this study, we have isolated rhizobacteria from rice varieties grown under aerobic conditions. Seed germination test showed that strain Ekn 03 was significantly effective in stimulating germination, enhancing shoot and root length, and increasing dry matter accumulation in treated rice plants as compared to the uninoculated plants. Under greenhouse conditions, strain Ekn 03 treated rice varieties showed an overall increase in plant height by 7.63%, dry matter accumulation by 16.23%, and total chlorophyll content by 76.47%. Soil acetylene reduction assay (ARA) (4.17 nmole ethylene/g soil/h) and in-planta ARA (4.2 × 10 nmole ethylene/mg fresh weight of plant/h) was significantly higher in Ekn 03 treated rice variety PB 1509 under aerobic conditions. Other rice varieties showed comparable performance on inoculation with strain Ekn 03. The endophytic and rhizospheric population of antibiotic tagged Ekn 03 was higher in the roots of PB 1509 (1.02 × 10 cfu/g and 5.8 × 10 cfu/g soil, respectively) compared to other rice varieties. 16S rDNA sequence analysis revealed that strain Ekn 03 was having 100% similarity with Pseudomonas protegens. This study suggests that strain Ekn 03 can be used as a microbial inoculant in rice plants under aerobic system of cultivation. This is the first report on the application of P. protegens as PGPR in rice.
Projections Onto Super-Half-Spaces for Monotone Variational Inequality Problems in Finite-Dimensional Space
The variational inequality problem (VIP) is considered here. We present a general algorithmic scheme which employs projections onto hyperplanes that separate balls from the feasible set of the VIP instead of projections onto the feasible set itself. Our algorithmic scheme includes the classical projection method and Fukushima's subgradient projection method as special cases.