Microbial biotechnology as an emerging industrial wastewater treatment process for arsenic mitigation: a critical review

Industrial wastewater pollution has become more grievous in the third world countries, where treatment and administration of industrial effluents are not being properly handled. About 80% of wastewater having arsenic (As) contamination are due to impurities in pesticides, chromated copper arsenate (CCA) wood preservatives, municipal solid waste incineration; leather industry; and consumption in the industry. Arsenic is a toxic metalloid, which is considered as a severe menace to the life of plants, animals and humans. Some As species such as As(III) and As(V) cause harmful effects on plants and animals. In order to treat As in industrial wastewater, various conventional methods are being employed. However, these methods face limitations in form of missing technical expertise and low effectiveness. Recently, microbial As remediation of industrial water has been evolved as a promising technology due to its public acceptance and cost effectiveness. The current review, for the first time, comprehensively summarizes the role of microbial remediation of As in industrial wastewater. In contrast to phytoremediation, the goal of using microbes is that dissolved arsenic species are converted microbially to arsine gas which is released into the atmosphere at non-toxic levels (dilution effect). In contrast to phytoremediation where arsenic is accumulated in plant material (waste production), this will not produce any solid or liquid waste - and this is just a key benefit of themicrobial approach as the management of solid/liquid arsenic rich waste is a global concern and economic burden; however, it was so far only tested on laboratory scale with exception of biofilms that have been tested on pilot scale. Our review also indicated the huge undervalued potential and environmental friendly solution of microbial remediation of As contaminated industrial wastewater without solid/liquid waste production as conventional technologies do

Insights into effects of salt stress on the oil-degradation capacity, cell response, and key metabolic pathways of Bacillus sp. YM1 isolated from oily food waste compost

A novel bacterial strain, Bacillus sp. YM1, was isolated from compost for the efficient degradation of oily food waste under salt stress. The strain\u27s lipase activity, oil degradation ability, and tolerance to salt stress were evaluated in a liquid medium. Additionally, the molecular mechanisms (including key genes and functional processes) underlying the strain\u27s salt-resistant degradation of oil were investigated based on RNA-Seq technology. The results showed that after 24 h of microbial degradation, the degradation rate of triglycerides in soybean oil was 80.23% by Bacillus sp. YM1 at a 30 g L−1 NaCl concentration. The metabolizing mechanism of long-chain triglycerides (C50–C58) by the YM1 strain, especially the biodegradation rate of triglycerides (C18:3/C18:3/C18:3), could reach 98.65%. The most substantial activity of lipase was up to 325.77 U·L−1 at a salinity of 30 g L−1 NaCl. During salt-induced stress, triacylglycerol lipase was identified as the crucial enzyme involved in oil degradation in Bacillus sp. YM1, and its synthesis was regulated by the lip gene (M5E02_13495). Bacillus sp. YM1 underwent adaptation to salt stress through various mechanisms, including the accumulation of free amino acids, betaine synthesis, regulation of intracellular Na+/K+ balance, the antioxidative response, spore formation, and germination. The key genes involved in Bacillus sp. YM1\u27s adaptation to salt stress were responsible for the synthesis of glutamate 5-kinase, superoxide dismutase, catalase, Na+/H+ antiporter, general stress protein, and sporogenic proteins belonging to the YjcZ family. Results indicated that the isolated strain of Bacillus sp. YM1 could significantly degrade oil in a short time under salt stress. This study would introduce new salt-tolerant strains for coping with the biodegradation of oily food waste and provide gene targets for use in genetic engineering

Combating soil salinity with combining saline agriculture and phytomanagement with salt-accumulating plants

Salinity poses serious threats to landscapes across the globe, decreasing the capacity of all types of terrestrial ecosystems in providing services by threatening our biodiversity, lowering agricultural productivity, deteriorating the environment, contaminating groundwater below standard level, enhancing flood risks, food security issues and restricting the economic growth of a community. Reclamation measures are required to reverse the process of land degradation caused by salinization; otherwise, the trend towards salinization is expected to grow beyond control in developing countries. The scientific community and the policy-makers around the globe have been testing long-term technologies including physicochemical, conventional breeding and genetic engineering involving state of the art molecular tools for more than three decades. Nevertheless, they have failed due to reasons like non-technical feasibility reports, reliability and affordability issues coupled with sustainability constraints at field level. This review discusses the potential prospects of Pennisetum genus (Poaceae) for integrated, sustainable, robust and profitable saline agriculture based on phytoremediation agro-technique. Our approach is the first ever record, providing a novel insight into a cost-effective biotech agro-technique. Pennisetum species are environment-friendly future candidates with prospects for all stakeholders to materialize higher average productivity at the field level, posing lesser competition for resources with standard conventional crops