Avaliação da produção de complexo celulásico por diferentes isolados bacterianos utilizando bagaço de cana como substrato indutor

Abstract

The searching for new fuel sources has motivated new studies which aim to produce the second-generation of ethanol, also called 2G . However, the costs to produce that fuel are still high because the sugarcane bagasse is not considered a residue any more, but a subproduct that can generate income to the industries that produce it, being a vapor energy form to the company or an electricity source to sell. The use of the sugar cane bagasse to produce 2G ethanol requires a significant amount of lignocellulolitic enzymes. The main aim of this study is to reduce the cost of the production of these enzymes by means of studying isolated lignocellulolitic bacterium from Stenochironomus larva. The goal is to evaluate its productivity in several submersed fermentation processes and surface fermentations. Submersed fermentations were conducted using sugar cane bagasse and soy meal as substrates and different concentrations were applied in culture media. A total of 11 isolated enzymes were evaluated initially, and re-selected at each new stage of the process. The enzyme cultures were conducted by the reduction sugars quantification and the results enabled us to demonstrate that the bacteria Sphingobium and Pseudomonas were the most productive when compared to the others. Our results have highlighted that those bacteria were strongly influenced by the addition of different organic nitrogen sources in the fermentation culture. From the introduction of those components, the enzyme activity became higher and this fact was corroborated by the index of 4.36 U/mg protein for Xilanase, 0.12 U/mg protein for FPase and 2.31 U/mg protein for CMCase.