PROGRAMA DE PÓS-GRADUAÇÃO – MESTRADO EM ... - Unisc

ABSTRACT
MICROALGAE CULTIVE IN FOTOBIORREATOR AND JOINT REACTOR
OBJECTIVING THE BIOREMEDIATION AND PRODUCTION OF BIOFUELS
This paper aimed to improve the tubular fotobiorreator type bubble column bench
and produce a mixed system for cultivation of microalgae, aiming the bioremediation
and biofuels production. As a way of cultivate it was used the effluent coming from
the Wastewater Treatment Plant – UNISC. To monitor cell density and dry weight, it
was standardized a method using a spectrophotometer (ʎ=682 nm) with a correlation
coefficient R 2 >0,98. In the biomass recovery, it was evaluated the electroflotation
method and it was produced an electrode of iron plates. After improving the
fotobiorreator tubular bench there was an increase in cell density and dry biomass of
approximately 1.80 times. Using the method of enzymatic transesterification in situ, it
was possible to verify all the bioconversion of lipid extracted material that was
confirmed by analysis on HPLC and CG-MS. For the production of ethanol it was
used fungi filamentous concerning the microalgae biomass hydrolysis, followed by
fermentation of Saccharomyces cerevisiae. With the construction of a phototype
system for the mixed culture of microalgae, there has been the development of
various strains of microalgae, achieving maximum cell density of 25.48 x10 6 cells mL -
1
dry biomass of 0,62 g L -1 and lipid percentage of 1.36 % (without contribution of
CO 2 ). Already with CO 2 injection, in 15 days of cultivation, the maximum cell density
was obtained up to 26.97 x 10 6 cells mL -1 , dry biomass 0.72 g L -1 and lipid
percentage of 6.07 %. In assessing the bioremediation of effluent using mixed
system for the cultivation of microalgae without contribution of CO 2 , there was
significant reduction in the parameters of alkalinity, total phosphorus, ammonia
nitrogen and total Kjeldahl nitrogen, however, there was an increase in the DBO 5 and
DQO patterns. With the injection of CO 2 , the results were: alkalinity and DQO
increasing, ammonia nitrogen decreasing, total Kjeldahl nitrogen and DBO 5 In the
last experiment, the phosphorus concentration remained unchanged. Thus, it can be
concluded that the proposed systems are suitable for the production of microalgae,
the bioremediation of waste and the consequent production of biofuel.
KEYWORDS: Microalgae, in situ transesterification, bioethanol, biorremediation.