Leveraging artificial intelligence in bioelectrochemical systems.

Bioelectrochemical systems (BESs) are highly evolved and sophisticated systems that produce bioenergy via exoelectrogenic microbes. Artificial intelligence (AI) helps to understand, relate, model, and predict both process parameters and microbial diversity, resulting in higher performance. This approach has revolutionized BESs through highly advanced computational algorithms that best suit the systems' architecture.

The role of conductive nanoparticles in anaerobic digestion: Mechanism, current status and future perspectives.

In the current scenario, alternative energy sources are the need of the hour. Organic wastes having a larger fraction of biodegradable constituents present a sustainable bioenergy source. It has been reported that the calorific value of biogas generated by anaerobic digestion (AD) is 21-25 MJ/m3 with the treatment which makes it an excellent replacement of natural gas and fossil fuels and can reduce more than 80% greenhouse gas emission to the surroundings. However, there are some limitations associated with the AD process for instance ammonia build-up at the first stage reduces the rate of hydrolysis of biomass, whereas, in the last stage it interferes with methane formation. Owing to special physicochemical properties such as high activity, high reactive surface area, and high specificity, tailor-made conductive nanoparticles can improve the performance of the AD process. In the AD process, H2 is used as an electron carrier, referred as mediated interspecies electron transfer (MIET). Due to the diffusion limitation of these electron carriers, the MIET efficiency is relatively low that limits the methanogenesis. Direct interspecies electron transfer (DIET), which enables direct cell-to-cell electron transport between bacteria and methanogen, has been considered an alternative efficient approach to MIET that creates metabolically favorable conditions and results in faster conversion of organic acids and alcohols into methane. This paper discusses in detail the application of conductive nanoparticles to enhance the AD process efficiency. Interaction between microbes in anaerobic conditions for electron transfer with the help of CNPs is discussed. Application of a variety of conductive nanomaterials as an additive is discussed with their potential biogas production and treatment enhancement in the anaerobic digestion process.

Bioelectrofuel Synthesis by Nanoenzymes: Novel Alternatives to Conventional Enzymes.

Recent bioinspired efforts of designing novel nanoenzyme-based electrocatalysts are driven by the urgency of making bioelectrofuels more affordable and efficient. Unlike natural enzymes, nanoenzyme-modified electrodes with large surface areas enclose numerous biomimicking active sites to facilitate enhanced microbial growth followed by increased reactant-to-bioelectrofuel conversion.

Microbe-mediated sustainable bio-recovery of gold from low-grade precious solid waste: A microbiological overview.

In an era of electronics, recovering the precious metal such as gold from ever increasing piles of electronic-wastes and metal-ion infested soil has become one of the prime concerns for researchers worldwide. Biological mining is an attractive, economical and non-hazardous to recover gold from the low-grade auriferous ore containing waste or soil. This review represents the recent major biological gold retrieval methods used to bio-mine gold. The biomining methods discussed in this review include, bioleaching, bio-oxidation, bio-precipitation, bio-flotation, bio-flocculation, bio-sorption, bio-reduction, bio-electrometallurgical technologies and bioaccumulation. The mechanism of gold biorecovery by microbes is explained in detail to explore its intracellular mechanistic, which help it withstand high concentrations of gold without causing any fatal consequences. Major challenges and future opportunities associated with each method and how they will dictate the fate of gold bio-metallurgy from metal wastes or metal infested soil bioremediation in the coming future are also discussed. With the help of concurrent advancements in high-throughput technologies, the gold bio-exploratory methods will speed up our ways to ensure maximum gold retrieval out of such low-grade ores containing sources, while keeping the gold mining clean and more sustainable.

Cadmium-induced changes in vacuolar aspects of Arabidopsis thaliana.

We have examined the changes due to Cd treatment in the vacuolar form in root tip cortical cells in Arabidopsis thaliana employing a transformant with GFP fused to a tonoplast protein. A Cd-induced enhancement in complexity with general expansion of vacuolar system within 24 h was evident. The changes in the vacuolar form were dependent on the applied Cd concentrations. Concomitantly, as revealed through dithizone staining, Cd accumulated in the seedling roots exhibiting abundance of Cd-dithizone complexes in root tip, root hairs and vasculature. To get insight into the involvement of SNARE protein-mediated vesicle fusion in Cd detoxification, the magnitude of Cd toxicity in a couple of knock out mutants of the vacuolar Qa-SNARE protein VAM3/SYP22 was compared with that in the wild type. The Cd toxicity appeared to be comparable in the mutants and the wild type. In order to analyze the Cd effects at cellular level, we treated the Arabidopsis suspension-cultured cells with Cd. Cd, however, did not induce a change in the vacuolar form in suspension-cultured cells although Cd measured with ICP-MS was obviously taken up into the cell. The V-ATPase activity in the microsomal fractions from vacuoles isolated from A. thaliana suspension cultured cells remained unaffected by Cd. Changes in the levels of certain metabolites of Cd-treated cells were also not so distinct except for those of glutathione. The significance of findings is discussed.

Plant-driven removal of heavy metals from soil: uptake, translocation, tolerance mechanism, challenges, and future perspectives.

Increasing heavy metal (HM) concentrations in the soil have become a significant problem in the modern industrialized world due to several anthropogenic activities. Heavy metals (HMs) are non-biodegradable and have long biological half lives; thus, once entered in food chain, their concentrations keep on increasing through biomagnification. The increased concentrations of heavy metals ultimately pose threat on human life also. The one captivating solution for this problem is to use green plants for HM removal from soil and render it harmless and reusable. Although this green technology called phytoremediation has many advantages over conventional methods of HM removal from soils, there are also many challenges that need to be addressed before making this technique practically feasible and useful on a large scale. In this review, we discuss the mechanisms of HM uptake, transport, and plant tolerance mechanisms to cope with increased HM concentrations. This review article also comprehensively discusses the advantages, major challenges, and future perspectives of phytoremediation of heavy metals from the soil.

Characterization of seed germination, seedling growth, and associated metabolic responses of Brassica juncea L. cultivars to elevated nickel concentrations.

Seed germination and seedling growth responses of three Brassica juncea L. cultivars, namely Varuna, Kranti, and Pusa Jai Kisan, to nickel have been characterized. Ni suppressed the seed germination differentially, suppression being greater in cv. Kranti than in others. On the basis of seedling growth performance, cv. Varuna proved most tolerant to Ni. The Ni accumulation in seedlings differed strongly among the three cultivars. The lowest and highest Ni contents were observed in the seedlings of cvs. Kranti and Pusa Jai Kisan, respectively. Despite substantial Ni accumulation, cv. Varuna was most tolerant to Ni. Ni accumulation in seedlings was accompanied by differentially altered Fe and K contents and increased levels of non-protein thiols and free proline. The O2- and H2O2 contents and their respective scavenging enzymes in the seedlings responded differentially to the Ni treatment suggesting the involvement of redox imbalance in the development of Ni toxicity. Interestingly, the greater Ni tolerance of cv. Varuna coincided with the elevated constitutive activities of superoxide dismutase (SOD) and ascorbate peroxidase (APX). The data have implications for seedling establishment under Ni-rich conditions and in turn for phytoremediation.