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Increasing Productivity and Recovery of Paenibacillin from Producing Strains Through Biotechnology Approaches

Campbell, Emily Pauline
http://rave.ohiolink.edu/etdc/view?acc_num=osu1593952118064502

Abstract Details

2020, Doctor of Philosophy, Ohio State University, Food Science and Technology.
Uncontrolled microbial populations in food can cause product spoilage and foodborne illness. Discovery and development of novel methods to combat harmful microorganisms are needed. One way to combat harmful microorganisms is through production of antimicrobials from beneficial bacteria. Paenibacillin is a promising lantibiotic, produced by Paenibacillus polymyxa OSY-DF, with potency against Gram positive bacteria. Paenibacillin has the potential, as food additive, to protect against spoilage and pathogenic organisms. Further studies on paenibacillin (and similar peptides) are ordinarily limited due to low productivity of the producing organisms and lack of efficient methods to recover these antimicrobials from end products. The objective of this work was to improve the production and recovery of antimicrobials from the producer strain and utilize an inexpensive food byproduct for production of antimicrobials. Paenibacillin titer and production consistency was improved in the wildtype strain through ribosome engineering. A spontaneous mutant, Paenibacillus polymyxa OSY-EC, was able to produce high paenibacillin titer reliably so it was selected for further improvement studies. Additionally, a successfully scale-up of the production of paenibacillin from flask to 2-L bioreactor was completed. The production and recovery of paenibacillin in bioreactors was further improved by maximizing the partitioning of paenibacillin in the collected foam. This was completed through harvesting foam continuously throughout antimicrobial production and optimizing bioreactor conditions through response surface methodology. The optimal conditions increased paenibacillin concentration 48-fold, from 16 µg/ml, in bioreactions without foam collection, to 768 µg/ml collected in foamate. The optimized conditions also almost doubled the total mass yield of paenibacillin collected in foam (12,674 µg) when compared to the yield obtained using original bioreaction parameters (6,400 µg). This was a solvent-free method to concentrate peptides from a dilute solution. It allowed for scale-up of antimicrobial peptide production. A food byproduct, acid whey, was modified to support production of antimicrobials by novel antimicrobial producer strains. Four strains were screened for production of antimicrobials in acid whey: P. polymyxa OSY-EC, Bacillus velezensis CE2, B. velezensis GF610, and B. velezensis S3. Modifications were made to the acid whey to enhance its ability to support the growth and production of antimicrobials by tested strains; these include pH adjustment and fortification with yeast extract. Production of antimicrobials was highest when acid whey was adjusted to pH 7 with the addition of 1% w/v yeast extract. Compared to the other strains, P. polymyxa OSY-EC produced the highest levels of antimicrobials and the most diverse inhibition spectrum. Combination of these discoveries and methods could allow for even greater antimicrobial yield improvements. Foam separation combined with utilization of modified acid whey could produce a concentrated antimicrobial rich cultured whey. This could reduce concentrations steps required before addition to a product. The reported outcomes and methods improved the feasibility of commercial production and downstream processing of this novel antimicrobial peptide.
Ahmed Yousef (Advisor)
V.M. Balasubramaniam (Committee Member)
Rafael Jimenez-Flores (Committee Member)
Jiyoung Lee (Committee Member)
167 p.
Food Science
Paenibacillin; Bacteriocin; Strain improvement; Bioreaction; Foam separation; Purification; Acid whey

Recommended Citations

Citations

  • Campbell, E. P. (2020). Increasing Productivity and Recovery of Paenibacillin from Producing Strains Through Biotechnology Approaches [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1593952118064502

    APA Style (7th edition)

  • Campbell, Emily. Increasing Productivity and Recovery of Paenibacillin from Producing Strains Through Biotechnology Approaches. 2020. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1593952118064502.

    MLA Style (8th edition)

  • Campbell, Emily. "Increasing Productivity and Recovery of Paenibacillin from Producing Strains Through Biotechnology Approaches." Doctoral dissertation, Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1593952118064502

    Chicago Manual of Style (17th edition)

osu1593952118064502
110
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