Effects of Low-Shear Modeled Microgravity on the Characterization of Recombinant β-D-Glucuronidase Expressed in Pichia pastoris

Abstract

In this study, we used a high-aspect-ratio vessel (HARV), which could model environment of microgravity on ground to investigate for the first time the effects of low-shear modeled microgravity (LSMMG) on the characterization of recombinant β-D-glucuronidase expressed in Pichia pastoris. The β-D-glucuronidase gene (GenBank accession no. EU095019) derived from Penicillium purpurogenum Li-3 encoding β-D-glucuronidase (PGUS) was expressed in P. pastoris GS115 in two different environments of LSMMG and normal gravity (NG). Results manifested that both LSMMG and NG conditions had insignificant effects on temperature and pH activity (optimal temperature and pH were 55 and 5.0 °C, respectively) and characteristic stability of recombinant PGUS. However, the catalytic activity of recombinant PGUS expressed under LSMMG was less affected by metal ions and EDTA as compared with that of NG. Furthermore, K (m) value of the recombinant PGUS expressed under LSMMG was nearly one fifth of that under NG (1.72 vs. 7.72), whereas catalytic efficiency (k (cat)/K (m)) of PGUS expressed under LSMMG (13.55) was 3.7 times higher than that of NG (3.61). The results initially reveal the significant alterations in catalytic properties of recombinant enzyme in response to LSMMG environment and have potential application in bioprocessing and biocatalysis.

Enhancement of recombinant β‐D‐glucuronidase production under low‐shear modeled microgravity in Pichia pastoris

“…26 In this study, the reason for enhancement of PGUS expression may be related to genes transcription. A significant number of yeast genes were found to be up-or downregulated by more than one to seven-fold as a result of growth under LSMMG analyzed using the DNA microarray method.…”

Advances in engineered microorganisms for improving metabolic conversion via microgravity effects

“…These results suggested that microgravity effects could be used for efficient production of recombinant proteins from engineered microorganisms. Interestingly, the enzyme catalysis process was also changed under microgravity [25][26][27]. The activities of intracellular antioxidant enzymes, superoxide dismutase and catalase, were higher under space microgravity condition [25].…”

“…The activities of intracellular antioxidant enzymes, superoxide dismutase and catalase, were higher under space microgravity condition [25]. Qi et al revealed the significant alterations in catalytic properties of the recombinant β-glucuronidase in response to low-shear modeled microgravity effect [27]. The catalytic efficiency (kcat/Km) of this enzyme expressed by E. coli was 3.7 times higher under microgravity than under which of normal gravity ( Table 1).…”

Magnetic Field Is the Dominant Factor to Induce the Response of Streptomyces avermitilis in Altered Gravity Simulated by Diamagnetic Levitation

“…Spaceflight has been reported to affect microbial cellular processes, such as cell growth [1], gene expression [2], and so on, therefore potentially producing unexpected (and possibly dangerous) changes in the natural biota within the space craft. For earth based organisms, microgravity is a key factor of the space condition, since all earth based organisms have been evolving under a 1g field for millions of years.…”