Microbial Technologies Employed for Biodegradation of Neonicotinoids in the Agroecosystem

Abstract

Neonicotinoids are synthetic pesticides widely used for the control of various pests in agriculture throughout the world. They mainly attack the nicotinic acetylcholine receptors, generate nervous stimulation, receptor clot, paralysis and finally cause death. They are low volatile, highly soluble and have a long half-life in soil and water. Due to their extensive use, the environmental residues have immensely increased in the last two decades and caused many hazardous effects on non-target organisms, including humans. Hence, for the protection of the environment and diversity of living organism’s the degradation of neonicotinoids has received widespread attention. Compared to the other methods, biological methods are considered cost-effective, eco-friendly and most efficient. In particular, the use of microbial species makes the degradation of xenobiotics more accessible fast and active due to their smaller size. Since this degradation also converts xenobiotics into less toxic substances, the various metabolic pathways for the microbial degradation of neonicotinoids have been systematically discussed. Additionally, different enzymes, genes, plasmids and proteins are also investigated here. At last, this review highlights the implementation of innovative tools, databases, multi-omics strategies and immobilization techniques of microbial cells to detect and degrade neonicotinoids in the environment.

Contribution of insect gut microbiota and their associated enzymes in insect physiology and biodegradation of pesticides

“…The other major pesticide-consuming countries are the United States, Argentina, Thailand, Brazil, Italy, France, Canada, Japan, and India ( Olisah et al, 2019 ). These agrochemicals are extensively introduced into modern agriculture and urban ecosystems during their production, transportation, improper storage and unwise applications, which cause severe environmental threats ( Ahmad et al, 2021 ). Local governments and environmental protection agencies regulate the production of pesticides and their applications.…”

Phytochemicals, Probiotics, Recombinant Proteins: Enzymatic Remedies to Pesticide Poisonings in Bees

“…Bees biosynthesize limited types of enzymes endogenously that can be enhanced by phytochemicals, but a large pool of candidate bacteria could generate more types of enzymes to efficiently detoxify various pesticides that bees cannot. Bees obtain exogenous bacteria from natural food (namely, horizontal transmission) or endogenous bacteria mainly from former generations (vertical transmission), with the latter being dominant in eusocial bees (honey bees and bumble bees) in nature. ,, In addition, more exogenous bacteria may be used for probiotic formulations that are (1) found in the environment (soil, water, or sediment) and selected for bioremediation of pesticide-contaminated environments, (2) found in plants, animals, and insects that evolved to be capable of detoxifying pesticides, or (3) currently used in probiotics for humans, animals, and bees. ,− A series of bacteria have demonstrated the capacity to detoxify pyrethroids, − organophosphates, ,, neonicotinoids, − a combination of several insecticides, and herbicides and fungicides (Supporting Information Table 2). More bacterial candidates can be discovered by genomic and omic technology as well as microbe databases. ,,− …”

“…Detoxification genes from the above candidate bacteria as well as any other prokaryotes (e.g., fungi) or eukaryotes (e.g., algae, plants, insects, animals, human beings) can be used to manufacture enzymatic r-proteins when expressed via vectors (either bacteria, fungi, insect, or animal cells) (Supporting Information Table 2). Different enzymes have been tested to efficiently detoxify pyrethroids, , organophosphates, , neonicotinoids, ,, or a combination of multiple insecticides. ,, The detoxification of fungicides and herbicides needs more investigation as widespread chronic toxicity caused by fungicides and herbicides is becoming a concern for bee health. , Finally, research into nanoenzymes could create alternatives to r-proteins and simplify complex manufacturing processes …”

“…The microbial ecology of bee guts should be taken into consideration when selecting appropriate microbe species/strains or enzymes, since the detoxification capability of both microbes and enzymes are affected by factors such as pH, temperature, and oxygen. , Most microbes and enzymes prefer slightly acidic environments over slightly basic environments to achieve optimal detoxification. − In contrast, honey bees have highly acid guts which may reduce the pool of candidate bacteria and enzymes for 3P. ,, For enzymes, however, a series of techniques can stabilize the enzymatic function, allowing for more flexibility when selecting candidate enzymes. This can be achieved by various immobilization techniques that protect enzymatic structure, such as encapsulation or cross-linking by microparticles. , Food passes through bee guts in about 3 days so candidate 3P should react to pesticides rapidly to avoid pesticide absorption and consequential toxicity.…”

Integrated Electrochemical Oxidation and Biodegradation for Remediation of a Neonicotinoid Insecticide Pollutant

“…The quantity of pesticide consumption, direct or indirect, by target pests is an effective outcome for pest control. , But they are toxic to the environment and human health, leading to various types of pollution such as air, soil, water, etc . Global pesticide consumption, estimated at approximately 0.002 billion tonnes annually, underscores the extensive reliance on these chemicals worldwide. − Due to the extensive usage of insecticides in both agricultural and nonagricultural sectors, several pesticide formulations were developed and brought onto the market. , Notably, nicotinoids, constituting nearly 25% of the global pesticide market, contribute significantly to the universal dilemma posed by pesticides. The ubiquity of nicotinoids exacerbates environmental degradation and poses hazards to ecosystems. , …”