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The objective of this study was to monitor the influence of Xanthomonas spp. and fermentation time on the production, properties, and composition of xanthan gum, verifying how these variables affect the biopolymer synthesis and properties. Three strains were monitored for 168 h of fermentation. Every 24 h, a sample was collected to determine cell growth, gum production, and substrate consumption. Fourier transform infrared, X‐ray diffraction, rheology, molecular characterization, thermogravimetric analysis, sugars, and acids analyzes were performed to characterize the gums produced and to identify possible differences in these properties and composition. The results showed the influence of strain and the fermentation time in production (Pr645 = 0.047 g L−1 h−1, Pr290 = 0.039 g L−1 h−1, Pr1155 = 0.149 g L−1 h−1) and gum quality, since the viscosity was highest in the first 48 h for strains 290 (148.71 MPa s−1) and 645 (135.28 MPa s−1), while for Strain 1155, the maximum value identified for this property was 90.48 MPa s−1. These results are of practical importance, since they allow obtaining better quality xanthan, enabling reduction of production costs. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48557.

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http://dx.doi.org/10.5007/1984-9222.2016v8n16p75Este artigo é uma versão adaptada de minha dissertação que analisa a trajetória de Lúcio José Maria de Souza, um africano liberto que enfrenta a resistência das autoridades policiais baianas, quando de seu desembarque no porto da cidade do Salvador, em 1871, após estada de onze meses na cidade de Lagos, Nigéria (África). Através da abordagem micro histórica e do método indiciário de investigação, analisam-se as estratégias e mecanismos utilizados por aquele africano em defesa de sua liberdade.