BIO-SPECKLE FOR MICROALGAE GROWTH MONITORING IN LABORATORY SCALE PHOTOBIOREACTOR

Abstract

Microalgae are widely used in different industries – pharmaceutical, cosmetic, in those dealing with pollution
prevention, aquaculture and especially biofuels. Because of the wide range of use, there is an active interest in
microalgae large-scale cultivation. Standard techniques for algae biomass production requires cultivation in
nutritious culture media, and well-defined external parameters, such as controlled conditions of light intensity,
temperature and aeration gas. Commercial production of microalgae is expensive, and the addition of nutrients in
culture media contributes to its high cost. The evaluation of the quality of culture media using wastewater
effluents or agro-industrial waste can be a way to reduce algal cultures costs. This research aims to develop a
noninvasive method for the testing of effectiveness of agro-industrial waste, previously treated, as culture media
through daily monitoring of population increase microalgae. We found that it is possible to detect the growth of
the microorganisms by using statistical cumulants as numerical approaches for analyzing the dynamic speckle
patterns produced by samples of Chlrorella Vulgaris algae cultivated in bold basal culture medium and in
vinasse,(byproduct of the sugar industry) pre-treated to improve its effectiveness.