Recycling of spent mushroom substrate biowaste as an Anti-UV agent for Bacillus thuringiensis

• Published in: Sustainable chemistry and pharmacy 2022-12, Vol.30, p.100811, Article 100811
• Main Authors: Rao, Wenhua, Zhang, Dingyang, Guan, Xiong, Pan, Xiaohong
• Format: Article
• Language: English
• Subjects: Anti-UV activity; Bacillus thuringiensis; carbohydrates; fermentation; green chemistry; lignin; Lignin-carbohydrate complex; molecular weight; reactive oxygen species; spent mushroom compost; Spent mushroom substrate; sugar content; thermal stability; toxicity; ultraviolet radiation; wastes
• ISSN: 2352-5541; 2352-5541
• DOI: 10.1016/j.scp.2022.100811

It is highly desirable to develop a Bacillus thuringiensis (Bt) formulation with high UV resistibility to increase its application duration in the field. In this work, we studied spent mushroom substrate extract (SMSE) for its anti-UV activity on Bt. The results demonstrated that SMSE could efficiently protect the active components of Bt from UV irradiation. After 96 h of UV exposure, the residual toxicity of Bt fermentation of the SMSE (0.6%, w/v) treatment was 17 times higher than that of the control treatment. SMSE was mainly composed of lignin (77.69%), carbohydrate (7.58%) and protein (4.18%). The anti-UV activity was shown by the lignin and carbohydrate fractions, but not the protein fractions. In addition, it was found that lignin and lignin-carbohydrate complex (LCC) in the SMSE were a type of lignin with low sugar content, low thermal stability, narrow molecular weight distribution and were typical gramineous plant lignin. Lignin and LCC possessed highly UV-screening effects and reactive oxygen species scavenging ability that could improve the UV stability of Bt formulation. Our study provides a green method for the utilization of SMS biowaste and increased the UV stability of Bt formulation. The application of spent mushroom substrate (SMS) in Bacillus thuringiensis (Bt) can improve the UV stability of Bt and promote the sustainable utilization of SMS. [Display omitted] •Spent mushroom substrate extract (SMSE) can efficiently protect Bt from UV radiation.•Lignin and carbohydrate of the SMSE can eliminate ROS produce from UV radiation.•The structure of the lignin and lignin-carbohydrate complex of the SMSE was analysed.