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Master's Dissertation
DOI
Document
Author
Full name
Mireia Recio Mitter
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2019
Supervisor
Committee
Gomez, José Gregorio Cabrera (President)
Camargo, Lívia Seno Ferreira
Monteiro, Gisele
Tonso, Aldo
Title in Portuguese
Modificação da morfologia de células de Pseudomonas sp. LFM046 e avaliação do impacto no acúmulo de polihidroxialcanoato
Keywords in Portuguese
divisão celular
morfologia celular
polihidroxialcanoatos
Pseudomonas
sulA
Abstract in Portuguese
A morfologia celular tem sido apontada como um novo alvo na engenharia genética de bactérias na produção de compostos químicos de interesse industrial. Recentemente, uma série de trabalhos têm mostrado que a alteração da morfologia celular de bactérias pode levar a um maior acúmulo de polihidroxialcanoatos contendo monómeros de cadeia curta, um tipo de poliéster bacteriano. Neste trabalho, o efeito da alteração da morfologia celular é estudado em Pseudomonas sp. LFM046, uma cepa isolada de solo canavial que produz naturalmente polihidroxialcanoato contendo monómeros de cadeia média. A proteína SulA, inibidora da divisão celular, foi expressa de forma controlada na bactéria alvo para a obtenção de células filamentosas. O efeito da mudança morfológica no acúmulo do polímero foi determinado através de microscopia de fluorescência e análises químicas de amostras obtidas em cultivos em frascos agitados e em cultivos de batelada alimentada em biorreator. Além do estudo empírico, este trabalho propõe um modelo matemático para analisar a capacidade de acúmulo de polihidroxialcanoatos baseado na geometria da célula. Comprimentos celulares aumentados de Pseudomonas sp. LFM046 foram obtidos de forma controlada e a mudança morfológica resultou em um aumento de 10% no acúmulo de polihidroxialcanoato. Em cultivos de batelada alimentada a cepa modificada com indução apresentou um comprimento 10 vezes aumentado e acumulou 84% de polímero na massa seca celular, enquanto a cepa modificada sem indução ficou com o comprimento original e acumulou 76%.
Title in English
Modification of the morfology of Pseudomonas sp. LFM046 cells and analysis of the effect on polyhydroxyalkanoate accumulation.
Keywords in English
Pseudomonas
cell division
cell morphology
polyhydroxyalkanoates
sulA
Abstract in English
Modification of the morfology of Pseudomonas sp. LFM046 cells and analysis of the effect on polyhydroxyalkanoate accumulation. Cell morphology has been pointed out as a new target for genetic engineering of bacteria for bioproduction. Modifying the cell shape of bacteria has been reported to lead to increases in the accumulation of the short-chain-length type of the natural polyester polyhydroxyalkanoate. In this work, the impact of increasing cell length on the production of mediumchain-length polihidroxialcanoate by the natural producer Pseudomonas sp. LFM046 is studied. Therefore, the endogenous gene codifying the cell division inhibitor SulA was expressed in this cell strain and both the cell morphology and the polyhydroxyalkanoate accumulation were analyzed in shaken-flask and fed-batch bioreactor cultivations. Further, a mathematical model for predicting accumulation capacity based on cell morphology is proposed. The cell length was successfully increased in a controlled manner in the Brazilian sugarcane soil isolate and the polyhydroxyalkanoate accumulation resulted to be increased by 10% when cell length was increased 10 times. In bed-batch cultivations the modified strain acumulated 84% of polymer in cell dry weight when induced, and 76% without induction.
 
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Release Date
2021-10-07
Publishing Date
2019-11-19
 
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