Ethanol and Levan production by sequential bath using Zymomonas mobilis immobilized on alginate and chitosan beads/Producao de etanol e levana por batelada sequencial utilizando Zymomonas mobilis imobilizadas em esferas de alginato e quitosana

• Published in: Acta scientiarum. Technology 2016-07, p.263
• Main Authors: Santos, Vidiany Aparecida Queiroz, Cruz, Crispin Humberto Garcia
• Format: Article
• Language: Spanish
• ISSN: 1806-2563
• DOI: 10.4025/actascitechnol.v38i3.27646

Current study evaluates ethanol and levan production using Zymomonas mobilis immobilized on alginate and chitosan beads and assesses the capacity of the beads for reuse in sequential fermentations. Two experiments were carried out: In the first experiment [2.sup.(5-2)] design evaluated the following independent variables: sucrose concentration; pH; incubation time; temperature and agitation. In the second experiment, based on the best conditions observed in [2.sup.(5-2)], the capacity of the immobilization support reuse in subsequent fermentations was evaluated for 12 days. In experiments using fractionated factorial experimental design [2.sup.(5-2)] the best results by immobilized biomass (2.6 g [L.sup.-1]) and immobilization efficiency was shown by alginate and chitosan beads showed only 0.22 g [L.sup.-1]. Chitosan support provided the best rates to levan production (8.90 g [L.sup.-1]). Alginate support showed the highest values by ethanol production (93.4 g [L.sup.-1]). In batch sequential fermentation, re-using immobilization support, alginate support was efficient by maintaining the cellular viability on immobilized support (0.94 g [L.sup.-1]), levan production (21.11 g [L.sup.-1]) and ethanol production (87.21 g [L.sup.-1]). Chitosan support was inadequate for sequential batches since the beads dissolved after the second cycle. Keywords: biofuel, microbial polysaccharide, entrapment, fractionated factorial experiment. O objetivo deste estudo foi avaliar a producao de etanol e levana por Zymomonas mobilis imobilizadas em esferas de alginato e quitosana e avaliar a capacidade de reutilizacao das esferas em fermentacoes sequenciais. Dois experimentos foram realizados: no primeiro, [2.sup.(5-2)] foram avaliadas as variaveis independentes: concentracao de sacarose; pH; tempo de incubacao; temperatura e agitacao. O segundo experimento foi realizado com base nas condicoes otimas do ensaio [2.sup.(5-2)], onde foi avaliada a capacidade de reutilizacao dos suportes durante 12 dias. Para o experimento [2.sup.(5-2)], o suporte mais eficiente para a imobilizacao foi o alginato, com 2,6 g [L.sup.-1] de biomassa imobilizada enquanto o suporte quitosana apresentou apenas 0,22 g [L.sup.-1]. A producao de levana foi maior nos experimentos realizados com o suporte quitosana (8,90 g [L.sup.-1]). Os maiores valores de etanol foram obtidos nos experimentos com o suporte alginato (93,4 g [L.sup.-1]) Nos experimentos por batelada sequencial, com reutilizacao dos suportes, o