Banca de DEFESA: JEINNY CHRISTINE GOMES DOS SANTOS

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : JEINNY CHRISTINE GOMES DOS SANTOS
DATE: 23/03/2022
TIME: 13:00
LOCAL: Remoto
TITLE:

Evaluation of new release materials for volatile compounds attractive to fruit flies

KEY WORDS:

: natural biopolymers, release devices, tephritid

PAGES: 106
BIG AREA: Outra
AREA: Multidisciplinar
SUMMARY:

The lignocellulosic fibrous biomass found in sugarcane bagasse can be the raw material to produce cellulosic ethanol, through delignification processes to obtain fermentative sugars. The residue from this process is called black liquor, which is rich in lignin, an amorphous biopolymer with high energy value used mainly as fuel in the cogeneration of energy in bio-industries. As lignin is a biodegradable and therefore recyclable by-product, it has been attracting interest in areas such as medicine, pharmaceuticals, and agriculture. In agriculture, lignin is being studied as a coating for fertilizers and as a biopolymer carrying active compounds (pesticides and semiochemicals) for pest control. As the object of this study, lignin was used as a biopolymeric matrix carrying substances attractive to fruit flies of the species Ceratitis capitata and Anastrepha fraterculus. The attractive substances studied were: ethyl octanoate, an attractive semiochemical for fruit fly species; a mixture of synthetic compounds common to guava host volatiles and volatiles released by males of Ceratitis capitata, composed of (R)-(+)-limonene, (S)-(-)-limonene, ethyl octanoate, αcopaene and β-caryophyllene; and hexane extracts of volatiles obtained by the host fruit guava (Psidium guajava, L.). Release substrates based on crude lignin (BL) were prepared, namely: acid lignin (LA) and a hybrid (LQ), lignin and chitosan in a 1:1 mass ratio. Chitosan (Q) was used as a control treatment. All substrates were subjected to thermogravimetric techniques, infrared spectroscopy and scanning electron microscopy to investigate the adsorbent potential when impregnated with semiochemicals. Thermogravimetric isotherms at 30°C, together with solid phase microextractions were also performed, aiming to know the release kinetics of substrate+semiochemical systems. The extracts obtained were analyzed by gas chromatography coupled with mass spectrometry. Attractiveness bioassays with mated females of C. capitata and A. fraterculus were carried out to evaluate which system elicits attraction behavior in females of these species. Thermogravimetric tests (TG, DTG and DSC) with pure substrates, containing lignin, LB, LP and LQ, demonstrated greater thermal stability than substrate Q, and when impregnated with semiochemicals, all showed a mass loss around 70 %. The FTIR analysis showed characteristic bands of polymers and substances incorporated in the substrates. The images obtained by SEM revealed porous agglomerates on substrates containing lignin and a smooth and homogeneous surface on chitosan, which has already been described in the literature. The release isotherms showed mass losses around 30% (±1%). In the extracts of substrates impregnated with ethyl octanoate, evaluated by GCEM, a larger relative area of the ester in the LA substrate is observed, like the LQ hybrid, at the end of the release period. Behavioral bioassays revealed that the substrate formulations with LA, elicited greater attractiveness in mated females of the studied species. From the above, it is possible to conclude that lignin-based polymeric matrices can be used as attractive semiochemical carriers for fruit flies.

BANKING MEMBERS:
Presidente - 1294906 - RUTH RUFINO DO NASCIMENTO
Interna - 426640 - FABIANE CAXICO DE ABREU GALDINO
Externo ao Programa - 287.291.704-78 - JOÃO GOMES DA COSTA - EMBRAPA
Externa à Instituição - IARA SORDI JOACHIM BRAVO - UFBA
Externo à Instituição - JOHNNATAN DUARTE DE FREITAS