title: Microbial cell disruption for improving lipid recovery using pressurized CO2: Role of CO2solubility in cell suspension, sugar broth, and spent media.
abstract: The study of in situ gas explosion to lyse the triglyceride-rich cells involves the solubilization of gas (e.g., carbon dioxide, CO2) in lipid-rich cells under pressure followed by a rapid decompression, which allows the gas inside the cell to rapidly expand and rupture the cell from inside out. The aim of this study was to perform the cell disruption using pressurized CO2as well as to determine the solubility of CO2in Rhodotorula glutinis cell suspension, sugar broth media, and spent media. Cell disruption of R. glutinis was performed at two pressures of 2,000 and 3,500 kPa, respectively, at 295.2 K, and it was found from both scanning electron microscopy (SEM) and plate count that a substantial amount of R. glutinis was disrupted due to the pressurized CO2. We also found a considerable portion of lipid present in the aqueous phase after the disruption at P = 3,500 kPa compared to control (no pressure) and P = 2,000 kPa, which implied that more intracellular lipid was released due to the pressurized CO2. Solubility of CO2in R. glutinis cell suspension was found to be higher than the solubility of CO2in both sugar broth media and spent media. Experimental solubility was correlated using the extended Henry's law, which showed a good agreement with the experimental data. Enthalpy and entropy of dissolution of CO2were found to be -14.22 kJ mol-1and 48.10 kJ mol-1K-1, 9.64 kJ mol-1and 32.52 kJ mol-1K-1, and 7.50 kJ mol-1and 25.22 kJ mol-1K-1in R. glutinis, spent media, and sugar broth media, respectively. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:737-748, 2017.
authors.affiliation: Dave C. Swalm School of Chemical Engineering, Mississippi State University, Mississippi State, MS, 39762.
authors.forename: Md Shamim
authors.identifier: http://orcid.org/0000-0002-8706-2647
authors.initials: MS
authors.lastname: Howlader
authors.affiliation: Dave C. Swalm School of Chemical Engineering, Mississippi State University, Mississippi State, MS, 39762.
authors.forename: William Todd
authors.initials: WT
authors.lastname: French
authors.affiliation: Dept. of Biological Sciences, Mississippi State University, Mississippi State, MS, 39762.
authors.forename: Sara A
authors.initials: SA
authors.lastname: Shields-Menard
authors.affiliation: Dave C. Swalm School of Chemical Engineering, Mississippi State University, Mississippi State, MS, 39762.
authors.forename: Marta
authors.initials: M
authors.lastname: Amirsadeghi
authors.affiliation: Mississippi State Chemical Laboratory, Mississippi State University, Mississippi State, MS, 39762.
authors.forename: Magan
authors.initials: M
authors.lastname: Green
authors.affiliation: Mississippi State Chemical Laboratory, Mississippi State University, Mississippi State, MS, 39762.|Center for Advanced Vehicular System, Mississippi State University, Mississippi State, MS, 39762.
authors.forename: Neeraj
authors.initials: N
authors.lastname: Rai
mesh_terms: D056804:Biofuels; D002245:Carbon Dioxide / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D011312:Pressure; D012995:Solubility; D000073893:Sugars; D013816:Thermodynamics
chemical_list: D056804:Biofuels; D000073893:Sugars; D002245:Carbon Dioxide
keywords: biofuel; cell disruption; scanning electron microscopy; solubility; thermodynamic modeling