Biodegradation of Free Gossypol by Helicoverpa armigera Carboxylesterase Expressed in Pichia pastoris

Abstract

Gossypol is a polyphenolic toxic secondary metabolite derived from cotton. Free gossypol in cotton meal is remarkably harmful to animals. Furthermore, microbial degradation of gossypol produces metabolites that reduce feed quality. We adopted an enzymatic method to degrade free gossypol safely and effectively. We cloned the gene cce001a encoding carboxylesterase (CarE) into pPICZαA and transformed it into Pichia pastoris GS115. The target protein was successfully obtained, and CarE CCE001a could effectively degrade free gossypol with a degradation rate of 89%. When esterase was added, the exposed toxic groups of gossypol reacted with different amino acids and amines to form bound gossypol, generating substances with (M + H) m/z ratios of 560.15, 600.25, and 713.46. The molecular formula was C27H28O13, C34H36N2O6, and C47H59N3O3. The observed instability of the hydroxyl groups caused the substitution and shedding of the group, forming a substance with m/z of 488.26 and molecular formula C31H36O5. These properties render the CarE CCE001a a valid candidate for the detoxification of cotton meal. Furthermore, the findings help elucidate the degradation process of gossypol in vitro.

Evaluation of the Application Value of Cottonseed Protein Concentrate as a Feed Protein Source in Broiler Chickens

“…This result indicates that feeding a diet containing CPC may had adverse effects on liver health. The toxicity of free gossypol contained in CPC was primarily attributed to the aldehyde and hydroxyl groups within its structure [23]. This compound can accumulate within an animal liver and bind with metal ions and amino acid residues, resulting in damage to its original biological function and ultimately causing harm to liver function [24].…”

Effective Degradation of Free Gossypol in Defatted Cottonseed Meal by Bacterial Laccases: Performance and Toxicity Analysis

“…The generalist moth Helicoverpa armigera is an important pest on cotton plants and has evolved a strategy to detoxify gossypol. The carboxylesterase CarE and P450 cytochrome CYP9A12 are reported to participate in FG degradation by H. armigera [16,17].…”