Deslignificação do bagaço da casca do coco verde para aplicação em processos biotecnológicos.

Abstract

The production of enzymes by fermentative processes presents itself as a large area of study of biotechnology. The application of semi-solid fermentation for this purpose has received special attention, especially those involved in the degradation of complex plant macromolecules. Among these, the green coconut shell appears as a raw material that presents interesting characteristics, such as the low cost and the composition, which makes possible the use as a substrate for obtaining cellulolytic enzymes. One of the factors that can disrupt this process is the large amount of lignin present in coconut husk constitution that can cause a limitation in the growth of the microorganism used. The objective of this study was to evaluate the reduction of lignin content in the structure of this biomass by hydrothermal and alkaline pretreatment (NaOH - 3%), for later application in the production of enzymes. The operating temperature was 120°C and the incubation times were 60, 120 and 180 minutes. For characterization of coconut shell (or substrate) the lignin fractions, extractives and moisture of the natural biomass were determined and after pretreatment. The in natura and pre-treated materials were incubated at 30ºC for cellulase production (CMCase) by solid state fermentation using a fungal isolate, called F1C3, which was obtained in the thermophilic phase of a composting process. The application of the hydrothermal pretreatment did not cause major changes in the composition of the material, but the application of alkaline pretreatment with 3% sodium hydroxide promoted the reduction of the lignin content from 41.79 to 12.91% in time of 120 minutes and a temperature of 120 ° C. And although the coconut bagasse presented high concentrations of cellulose and the obtained lignin removal, the production of cellulase enzyme expressed in CMCase by Fungi F1C3 was not verified.