Date of Award

9-7-2017

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biology

First Advisor

Qingfang He

Abstract

Cinnamic acid is the precursor for phenylpropanoids, which play important roles in plant growth, development, and stress responses. It is highly beneficial to human health for its anticancer, antitoxic and anti-inflammatory functions. Currently, the major methods of industrial production of cinnamic acid are chemical synthesis and extraction from plants. However, these methods are often associated with low production yields and high costs. Cyanobacterial platforms could be highly suitable for phenylpropanoid production due to potential high yields and eco- friendly, cost- effective production processes. The primary purpose of this study is to explore the possibility of using the cyanobacterium Synechocystis PCC 6803 for biosynthesis of cinnamic acid. In this thesis research, I genetically engineered a strain of Synechocystis PCC 6803 to functionally express the Ava_3988 gene encoding a phenylalanine ammonia lyase (PAL), which converts phenylalanine into cinnamic acid. This gene was successfully inserted into the genome of Synechocystis PCC 6803. A fully segregated strain was obtained as verified by polymerase chain reactions (PCR). The expression of the gene in the cyanobacterial cells was confirmed by reverse transcriptase PCR (RT-PCR), SDS-PAGE, and western blotting. The production of cinnamic acid in the cyanobacterial cells was analyzed by HPLC, and the final production yield was determined to be about 1.4 mg/L. This research paves the way for eco-friendly and cost-effective production of cinnamic acid using cyanobacteria as cell factories.

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