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International Journal of Polymer Science
Volume 2014, Article ID 895237, 6 pages
http://dx.doi.org/10.1155/2014/895237
Research Article

Bioprocess Engineering Aspects of Biopolymer Production by the Cyanobacterium Spirulina Strain LEB 18

Biochemical Engineering Laboratory, College of Chemistry and Food, Federal University of Rio Grande, Avenida Italia, Km 8, P.O. Box 474, 96203-000 Rio Grande, RS, Brazil

Received 19 August 2014; Revised 15 November 2014; Accepted 24 November 2014; Published 11 December 2014

Academic Editor: Saad Khan

Copyright © 2014 Roberta Guimarães Martins et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Microbial biopolymers can replace environmentally damaging plastics derived from petrochemicals. We investigated biopolymer synthesis by the cyanobacterium Spirulina strain LEB 18. Autotrophic culture used unmodified Zarrouk medium or modified Zarrouk medium in which the NaNO3 content was reduced to 0.25 g L−1 and the NaHCO3 content reduced to 8.4 g L−1 or increased to 25.2 g L−1. Heterotrophic culture used modified Zarrouk medium containing 0.25 g L−1 NaNO3 with the NaHCO3 replaced by 0.2 g L−1, 0.4 g L−1, or 0.6 g L−1 of glucose (C6H12O6) or sodium acetate (CH3COONa). Mixotrophic culture used modified Zarrouk medium containing 0.25 g L−1 NaNO3 plus 16.8 g L−1 NaHCO3 with the addition of 0.2 g L−1, 0.4 g L−1, or 0.6 g L−1 of glucose or sodium acetate. The highest biopolymer yield was 44% when LEB 18 was growing autotrophically in media containing 0.25 g L−1 NaNO3 and 8.4 g L−1 NaHCO3.