Vermicomposting technology - A perspective on vermicompost production technologies, limitations and prospects.

The need for environmental sustainability while increasing the quantity, quality, and the rate of waste treatment to generate high-value environmental friendly fertilizer products is highly in demand. Vermicomposting is a good technology for the valorisation of industrial, domestic, municipal and agricultural wastes. Various vermicomposting technologies have been in use from time past to present. These technologies range from windrow, small - scale batch vermicomposting to large - scale continuous flow systems. Each of these processes has its own merits and demerits, necessitating advancement in the technology for efficient treatment of wastes. This work explores the hypothesis that the use of a continuous flow vermireactor system of a composite frame structure performs better than batch, windrow and other continuous systems operated in a single container. Following an in-depth review of the literature on vermicomposting technologies, treatment techniques, and reactor materials used, to explore the hypothesis, it was found that vermireactors operating in continuous flow fashion perform better in waste bioconversion than the batch and windrow techniques. Overall, the study concludes that batch techniques using plastic vermireactors predominate over the other reactor systems. However, the use of frame compartmentalized composite vermireactors performs considerably better in waste valorisation.

Green Synthesis of Bioplastics from Microalgae: A State-of-the-Art Review.

The synthesis of conventional plastics has increased tremendously in the last decades due to rapid industrialization, population growth, and advancement in the use of modern technologies. However, overuse of these fossil fuel-based plastics has resulted in serious environmental and health hazards by causing pollution, global warming, etc. Therefore, the use of microalgae as a feedstock is a promising, green, and sustainable approach for the production of biobased plastics. Various biopolymers, such as polyhydroxybutyrate, polyurethane, polylactic acid, cellulose-based polymers, starch-based polymers, and protein-based polymers, can be produced from different strains of microalgae under varying culture conditions. Different techniques, including genetic engineering, metabolic engineering, the use of photobioreactors, response surface methodology, and artificial intelligence, are used to alter and improve microalgae stocks for the commercial synthesis of bioplastics at lower costs. In comparison to conventional plastics, these biobased plastics are biodegradable, biocompatible, recyclable, non-toxic, eco-friendly, and sustainable, with robust mechanical and thermoplastic properties. In addition, the bioplastics are suitable for a plethora of applications in the agriculture, construction, healthcare, electrical and electronics, and packaging industries. Thus, this review focuses on techniques for the production of biopolymers and bioplastics from microalgae. In addition, it discusses innovative and efficient strategies for large-scale bioplastic production while also providing insights into the life cycle assessment, end-of-life, and applications of bioplastics. Furthermore, some challenges affecting industrial scale bioplastics production and recommendations for future research are provided.

Susceptibility and plant immune control-a case of mycorrhizal strategy for plant colonization, symbiosis, and plant immune suppression.

Plants and microbes (mycorrhizal fungi to be precise) have evolved together over the past millions of years into an association that is mutualist. The plants supply the fungi with photosynthates and shelter, while the fungi reciprocate by enhancing nutrient and water uptake by the plants as well as, in some cases, control of soil-borne pathogens, but this fungi-plant association is not always beneficial. We argue that mycorrhizal fungi, despite contributing to plant nutrition, equally increase plant susceptibility to pathogens and herbivorous pests' infestation. Understanding of mycorrhizal fungi strategies for suppressing plant immunity, the phytohormones involved and the signaling pathways that aid them will enable the harnessing of tripartite (consisting of three biological systems)-plant-mycorrhizal fungi-microbe interactions for promoting sustainable production of crops.

Aquatic Environment Exposure and Toxicity of Engineered Nanomaterials Released from Nano-Enabled Products: Current Status and Data Needs.

Rapid commercialisation of nano-enabled products (NEPs) elevates the potential environmental release of engineered nanomaterials (ENMs) along the product life cycle. The current review examined the state of the art literature on aquatic environment exposure and ecotoxicity of product released (PR) engineered nanomaterials (PR-ENMs). Additionally, the data obtained were applied to estimate the risk posed by PR-ENMs to various trophic levels of aquatic biota as a means of identifying priority NEPs cases that may require attention with regards to examining environmental implications. Overall, the PR-ENMs are predominantly associated with the matrix of the respective NEPs, a factor that often hinders proper isolation of nano-driven toxicity effects. Nevertheless, some studies have attributed the toxicity basis of observed adverse effects to a combination of the released ions, ENMs and other components of NEPs. Notwithstanding the limitation of current ecotoxicology data limitations, the risk estimated herein points to an elevated risk towards fish arising from fabrics' PR-nAg, and the considerable potential effects from sunscreens' PR-nZnO and PR-nTiO2 to algae, echinoderms, and crustaceans (PR-nZnO), whereas PR-nTiO2 poses no significant risk to echinoderms. Considering that the current data limitations will not be overcome immediately, we recommend the careful application of similar risk estimation to isolate/prioritise cases of NEPs for detailed characterisation of ENMs' release and effects in aquatic environments.

The genome of a subterrestrial nematode reveals adaptations to heat.

The nematode Halicephalobus mephisto was originally discovered inhabiting a deep terrestrial aquifer 1.3 km underground. H. mephisto can thrive under conditions of abiotic stress including heat and minimal oxygen, where it feeds on a community of both chemolithotrophic and heterotrophic prokaryotes in an unusual ecosystem isolated from the surface biosphere. Here we report the comprehensive genome and transcriptome of this organism, identifying a signature of adaptation: an expanded repertoire of 70 kilodalton heat-shock proteins (Hsp70) and avrRpt2 induced gene 1 (AIG1) proteins. The expanded Hsp70 genes are transcriptionally induced upon growth under heat stress, and we find that positive selection is detectable in several members of this family. We further show that AIG1 may have been acquired by horizontal gene transfer (HGT) from a rhizobial fungus. Over one-third of the genes of H. mephisto are novel, highlighting the divergence of this nematode from other sequenced organisms. This work sheds light on the genomic basis of heat tolerance in a complete subterrestrial eukaryotic genome.

Comparisons of the composition and biogeographic distribution of the bacterial communities occupying South African thermal springs with those inhabiting deep subsurface fracture water.

South Africa has numerous thermal springs that represent topographically driven meteoric water migrating along major fracture zones. The temperature (40-70°C) and pH (8-9) of the thermal springs in the Limpopo Province are very similar to those of the low salinity fracture water encountered in the South African mines at depths ranging from 1.0 to 3.1 km. The major cation and anion composition of these thermal springs are very similar to that of the deep fracture water with the exception of the dissolved inorganic carbon and dissolved O2, both of which are typically higher in the springs than in the deep fracture water. The in situ biological relatedness of such thermal springs and the subsurface fracture fluids that feed them has not previously been evaluated. In this study, we evaluated the microbial diversity of six thermal spring and six subsurface sites in South Africa using high-throughput sequencing of 16S rRNA gene hypervariable regions. Proteobacteria were identified as the dominant phylum within both subsurface and thermal spring environments, but only one genera, Rheinheimera, was identified among all samples. Using Morisita similarity indices as a metric for pairwise comparisons between sites, we found that the communities of thermal springs are highly distinct from subsurface datasets. Although the Limpopo thermal springs do not appear to provide a new window for viewing subsurface bacterial communities, we report that the taxonomic compositions of the subsurface sites studied are more similar than previous results would indicate and provide evidence that the microbial communities sampled at depth are more correlated to subsurface conditions than geographical distance.