Experimental study and kinetic modelling of bioethanol production from industrial potato waste

International audienceThe potato wastes constitute a major environmental concern due to their significant production in the potato processing industry. Due to their high organic content, this waste can constitute a very interesting Algerian resource for biofuel production. The objective of this study is the energy recovery of an industrial agro-food waste to produce bioethanol. This waste is a solid residue of chips manufacturing and mainly consists of potato starch. The conversion of this biomass was achieved using a chemical pretreatment with hydrochloric acid. The acid hydrolysis of potato starch with a ratio of material to acid solution of 1:2 (w/v) was enough to liberate a high amount of fermentable reducing sugar (159.3 g/l) contained in the potato waste. The hydrolysate obtained at the end was fermented using Saccharomyces cerevisiae yeast under the following conditions (pH 5, 30 degrees C, 100 rpm). The maximum yield of bioethanol (54.12 g/l) was achieved after 116 h. Thus, operating conditions used for the sugar fermentation were favorable and did not exhibit any sort of process inhibition. The Gompertz model was applied to experimental data, and kinetic fermentation parameters such as maximum ethanol concentration (P-m = 49.81 g/l), production rate (r(pm) = 0.87 g/(l h)), and lag phase (t(L) = 5.29 h) were accurately estimated. Those parameters can be used to investigate the economical feasibility for such industry. The results demonstrate that potato starch (by-product of the potato industry) has a great potential for bioethanol production

Indigenous microalgae strains characterization for a sustainable biodiesel production

International audienceMicroalgae have been widely recognized as a promising feedstock for sustainable biofuels production to tackle global warming and pollution issues related to fossil fuels uses. This study identified and analyzed indigenous microalgae strains for biodiesel production, specifically Chlorella vulgaris and Coelastrella thermophila var. globulina, from two distinct locations in Algeria. Molecular identification confirmed their identity, and the microalgae exhibited notable growth characteristics. Local Chlorella vulgaris and Coelastrella thermophila var. globulina showed a good growth and high biomass yield, compared to Chlorella vulgaris CCAP211/11B reaching a weight of 1.48 g/L, 1.95g/L and 2.10 g/L, respectively. Lipids content of local Chlorella vulgaris, Coelastrella thermophila var. globulina, and Chlorella vulgaris CCAP211/11B, were found to be 31.39 ± 3.3%, 17 ± 2.26%, and 19 ± 0.64%, respectively. Chlorella vulgaris stood out as a candidate for biodiesel production due to its equilibrium between SFA and PUFA (43.24% and 45.27%). FAs are predominated by SFA and MUFA for Coelastrella thermophila var. globulina with value of 81.49% (SFA+MUFA). Predicted biodiesel qualities are complying with ASTM6751 and EN14214 standards. Studied microalgae have therefore a promising potential for biodiesel production. However, optimising cultivation conditions is necessary to enhance biomass and lipids yield at large scale. This article is protected by copyright. All rights reserved