Navegando por Autor "Reis, Cristiano Eduardo Rodrigues"

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    An unconventional two-stage cultivation strategy to increase the lipid content and enhance the fatty acid profile on Chlorella minutissima biomass cultivated in a novel internal light integrated photobioreactor aiming at biodiesel production.
    (2020) Amaral, Mateus de Souza; Loures, Carla Cristina Almeida; Pedro, Guilherme Arantes; Reis, Cristiano Eduardo Rodrigues; Castro, Heizir Ferreira de; Naves, Fabiano Luiz; Silva, Messias Borges; Prata, Arnaldo Márcio Ramalho
    Biodiesel quality is dependent upon the fatty acids distribution of the raw material used in the trans/ esterification reactions. While microalgae cells are regarded as potential oil suppliers for the biodiesel production chain, a common criticism is related to the low lipid productivities and often to a poor fatty acid distribution. In the present work we propose to submit microalgal cultivation to a second stage with nutritional stress by a simple addition of a 70% nitrate source depleted medium at the beginning of stationary phase, without harvesting cells, saving time and water. Chlorella minutissima was cultivated in a novel unconventional photobioreactor, named Internally Illuminated Integrated Photobioreactor (ILI- PBR), to verify the efficiency of the proposed strategy. Biomass concentration, lipid content and volu- metric lipids productivity increased 24.9%, 120.7% and 55.6%, respectively, from Stage 1 to Stage 2, when ILI-PBR was illuminated by constant blue LED and 0.5 vvm of aeration. The fatty acid profiles, evaluated in terms of LED illumination (white, red and blue), showed a predominance of palmitic acid in all cases (59.49%, 57.28% and 46.51%, respectively), which allowed to enhance some biodiesel properties such as cetane number, cold filter plugging point, density and kinematic viscosity, according to international specifications.
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    Highly wet Chlorella minutissima biomass for in situ biodiesel production and residual biomass rich in labile carbohydrates.
    (2022) Pedro, Guilherme Arantes; Amaral, Mateus de Souza; Pereira, Félix Monteiro; Flumignan, Danilo Luiz; Rós, Patrícia Caroline Molgero da; Reis, Cristiano Eduardo Rodrigues; Silva, Messias Borges
    This study evaluated the use of biomass of Chlorella minutissima grown in 40-L photobioreactors using a Guillard f/2 biomass at over 80% moisture content as feedstock to produce ethyl esters. The study design investigated the infuence of acid catalyst type (HCl or H2SO4) and concentration (0.3 or 0.6 mol L−1), co-solvent to ethanol ratio (1:10 or 1:5 v/v), and acyl acceptor to biomass ratio (25 mL g−1 or 50 mL g−1) on ester yield and conversion. An L8 Taguchi design was used to evaluate the infuence of the factors, demonstrating a range of conversion ranging from 37 to 98%. Furthermore, the efects of reaction conditions on the residual biomass were assessed by measuring the concentration of acid-labile carbohydrates, which could be utilized in integrated sugar- and lipid-based algal refneries. It was found that in situ transesterifcation using HCl can provide easily accessible and fermentable carbohydrates at concentrations of about 32 wt% in residual biomass. In this sense, the fndings of this study demonstrate a further step in the integration of microalgae biomass in the development of liquid-fuel biorefneries.