Neotropical Biodiversity as Microbial Frontline for Obtaining Bioactive Compounds with Potential Insecticidal Action

Abstract

The occurrence of insect pests in crops directly affects the yield of plants and grains. This scenario led to the mass investigation of chemical products that overcome these adversities and provide control potential. Nonetheless, over the years, this strategy resulted in high production costs, generation of waste harmful to the environment, and resistance of target insects. The adoption of alternative practices, such as the formulation and production of products of microbial origin, emerges as an encouraging tool compared to control alternatives, indicating a sustainability bias, and allowing a reduction in the risks of human and animal contamination. The purpose of this study was to perform bioprospecting for microbial agents with potential insecticidal effects. The isolated microorganisms were submitted to submerged fermentation, at 28 °C and 120 rpm, for seven days. The fermented broth was filtered using a vacuum pump and centrifuged at 3200× g and 10 °C for 10 min. Initially, 163 microbial agents were collected. Subsequently, a pre-selection of the 50 most promising bioagents was conducted, based on the mortality rates (%) of the applied isolates to target pests. Furthermore, a global mathematical modeling design was created, indicating the best potential microorganisms. Moreover, to stipulate the difference between treatments, dilutions of the fermented broths of each microorganism were conducted (n × 10−5–n × 10−8). Mortality was maximum (100%) for Helicoverpa zea and Euschistus heros. Other encouraging results were indicated in the control of Anticarsia gemmatalis and Chrysodeixis includens (up to 87.5%) and Elasmopalpus lignosellus (up to approximately 83.5%). Fungal isolates were identified as Talaromyces piceae. Among the bacteria, based on sequencing of the 16S ribosomal gene, the isolates were identified as Lysinibacillus fusiformis, Paenibacillus ottowii, and Clostridium sphenoides. The results obtained are relevant to the scientific community and, especially, are interesting for companies that are operating in this field in the agricultural sector.