Date of Award

2016

Document Type

Open Access Master's Thesis

Degree Name

Master of Science in Chemical Engineering (MS)

Administrative Home Department

Department of Chemical Engineering

Advisor 1

Caryn Heldt

Committee Member 1

Ebenezer Tumban

Committee Member 2

Timothy Eisele

Abstract

Viral infectious diseases cause millions of deaths and severe illness all around the world affecting public health and economics. Viral vaccines are helping to fight against viral diseases, but current vaccines are expensive and unavailable, especially in poor and developing countries. When measuring the entire manufacturing processing, the downstream processing of vaccines is the major cost of production. Our goal for this research is to develop a low-cost alternative downstream processing platform for new vaccine manufacturing infrastructures. We have developed a novel osmolyte flocculation method for viral particles. To create a platform purification for several types of viral particles, we used two model viruses: porcine parvovirus (PPV) and Sindbis virus (SINV). PPV is a non-enveloped virus, one of smallest known mammalian viruses with a diameter of approximately 20 nm. The enveloped virus, SINV, has a size of 48-52 nm. Using mannitol osmolyte flocculation we demonstrated recovery for both viruses by diafiltration using a micropore membrane. This will allow easy scale-up to production scale and creates a low-cost platform. Our lab’s previous study showed that osmolyte flocculation was specific to viruses as compared to proteins which are present as the contaminants in the process. This preferential flocculation is due to the active hydrophobic surface differences on viruses and protein surfaces. We studied the effect of membrane pore size on the recovery of viruses and were able to achieve 60% recovery of infectious PPV using a 0.1 μm and 500 kDa pore size filters. Recovery of infectious SINV was 79% using 0.1 μm and 96% using 500 kDa pore size membrane filter. Increasing the concentration of virus results in enhanced recovery of infectious particles, but at high concentration, membrane pores can get blocked, causing membrane fouling. We also examined the purity of the recovered virus samples for DNA and protein contaminants. In conclusion, we have developed a novel purification process that was able to purify and recover infectious viral particles using large pore size filters, which can decrease overall processing costs.

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