Application of a series of biomarkers in Scallop Chlamys farreri to assess the toxic effects after exposure to a priority hazardous and noxious substance (HNS)-Acrylonitrile

Degradation of Nitriles by Mixed Biofilms of Nitrile-Hydrolyzing Bacteria in Submerged Packed-Bed Reactor

Degradation of nitriles by mixed biofilms of nitrile-hydrolyzing bacteria Alcaligenes faecalis 2 and Rhodococcus ruber gt 1 grown on basalt and carbon carriers, in a submerged packed-bed reactor was studied. It was shown the formation of a massive mixed biofilm of Al. faecalis 2 and R. ruber gt 1 and the effective removal of nitriles and products of their degradation from the reaction medium. After the accumulation of carboxylic acid and some of the unprocessed substrate, the system adapts to 600-1000 h of biofilter operation, which is expressed in a decrease in the content of substrate and reaction products in the medium. The rate of acetonitrile and acrylonitrile utilization was 0.072-0.086 and 0.039-0.215 g/h, respectively, and acrylonitrile utilization with maximum rate was realized by a mixed biofilm on carbon fibers. Biofilms grown on mixed fibers in a "sandwich"-type reactor had the best characteristics for the transformation of aceto- and acrylonitrile (removal capacity of 99.6-99.9%, nitrile utilization rate of 0.080-0.095 g/h). Biofilms grown on basalt fiber with a diameter of 4-12 μm are also well suited for the degradation of acetonitrile (removal capacity of 100%, nitrile utilization rate of 0.086 g/h). The results of metagenomic analysis showed the resistance of Al. faecalis 2 and R. ruber gt 1 mixed biofilms against leaching from a biofilter and to competitive growth in an open system, indicating the advantages of biofilms over homogeneous biomass for wastewater treatment from nitrile compounds. Biofilms of two species of nitrile hydrolyzing bacteria on basalt and carbon fibers effectively purify water from nitriles in a submerged packed-bed reactor.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12088-022-01030-z.

Acute toxic effect of typical chemicals and ecological risk assessment based on two marine microalgae, Phaeodactylum tricornutum and Platymonas subcordiformis

With the increasing demand for typical hazardous and noxious substances (HNS) in chemical industry, there is an increased leakage risk of these HNS during transportation by vessel and storage nearby seashore. In this study, the acute toxicity of nonylphenol, butyl acrylate and 1, 2-dichloroethane to Phaeodactylum tricornutum (P. tricornutum) and Platymonas subcordiformis (P. subcordiformis), was investigated to assess their ecological risk. The results showed that the three kinds of HNS showed significant time- and dose-dependent patterns on the growth inhibition of two marine microalgae. The 96 h-EC₅₀ of nonylphenol, butyl acrylate and 1, 2-dichloroethane on P. tricornutum was 1.088, 45.908 and 396 mg L^-1, respectively, and the 96 h-EC₅₀ of that on P. subcordiformis was 0.851, 52.621 and 389 mg L^-1, respectively. It was a common method to evaluate the harm of pollutants to organisms by calculating HC₅ value (the minimum pollutant concentration value harmful to 95 % of the studied species, which was no-effect concentration) with Species Sensitivity Distribution (SSD). On the basis of EC₅₀, the ecological risk assessment was further carried out, and HC₅ value of nonylphenol and 1, 2-dichloroethane to aquatic organism was 0.079 and 44 mg L^-1, respectively.

Extremophile Microbial Communities and Enzymes for Bioenergetic Application Based on Multi-Omics Tools

Abstract: Genomic and proteomic advances in extremophile microorganism studies are increasingly demonstrating their ability to produce a variety of enzymes capable of converting biomass into bioenergy. Such microorganisms are found in environments with nutritional restrictions, anaerobic environments, high salinity, varying pH conditions and extreme natural environments such as hydrothermal vents, soda lakes, and Antarctic sediments. As extremophile microorganisms and their enzymes are found in widely disparate locations, they generate new possibilities and opportunities to explore biotechnological prospecting, including biofuels (biogas, hydrogen and ethanol) with an aim toward using multi-omics tools that shed light on biotechnological breakthroughs.

Toxicity of ammonia, nitrite and nitrate to Litopenaeus vannamei juveniles in low-salinity water in single and ternary exposure experiments and their environmental implications

Information on toxicity of nitrogen compounds for Litopenaeus vannamei in coastal ecosystems and culture under low salinity is scarce. Acute toxicity trials were conducted in L. vannamei to determine the single and combined effects of ammonia, nitrite and nitrate at a salinity of 3 g/L. The 96 h-LC₅₀ was 29.0 mg/L for total ammonia nitrogen (TAN); 10.6 mg/L for nitrogen as nitrite (NO₂^--N); and 900 mg/L for nitrogen as nitrate (NO₃^--N). The joint effects of ammonia, nitrite and nitrate exposure were antagonistic at 24-72 h; and additive from 72 to 96 h. The proposed safety levels of single exposure to TAN, NO₂^--N and NO₃^--N for L. vannamei are 1.45, 0.53 and 45.0 mg/L, respectively. When in mixture, the proposed level of TAN/NO₂^--N/NO₃^--N is 0.05 TU (Toxicity Unit) corresponding to 0.48, 0.08 and 14.6 mg/L of TAN, NO₂^--N and NO₃^--N, respectively.

Thermophiles and the applications of their enzymes as new biocatalysts

Ecological and efficient alternatives to industrial processes have sparked interest for using microorganisms and enzymes as biocatalysts. One of the difficulties is finding candidates capable of resisting the harsh conditions in which industrial processes usually take place. Extremophiles, microorganisms naturally found in "extreme" ecological niches, produce robust enzymes for bioprocesses and product development. Thermophiles like Geobacillus, Alyciclobacillus, Anoxybacillus, Pyrococcus and Thermoccocus are some of the extremophiles containing enzymes showing special promise for biocatalysis. Glutamate dehydrogenase used in food processes, laccases and xylanases in pulp and paper processes, nitrilases and transaminases for pharmaceutical drug synthesis and lipases present in detergents, are examples of the increasing use of enzymes for biocatalytic synthesis from thermophilic microorganisms. Some of these enzymes from thermophiles have been expressed as recombinant enzymes and are already in the market. Here we will review recent discoveries of thermophilic enzymes and their current and potential applications in industry.