NZY Auto-Induction LB medium (powder)

Description: NZY Auto-Induction LB medium (powder) is an innovative culture medium for growing Escherichia coli to high cell densities while obtaining high-levels of recombinant protein expression with IPTG-inducible bacterial expression systems. This medium does not require the addition of isopropyl β-D-1-thiogalactopyranoside (IPTG) and consequently to monitor cell growth. The method is based on the presence of medium components that are metabolized differentially to promote culture growth to high cell densities and subsequently induce protein expression from lac-based promoters. NZY Auto-Induction LB medium (powder) offers great convenience allowing high cell densities and spontaneous gene induction without monitoring cell grow, saving you more time to perform other tasks. NZY Auto-Induction LB medium (powder) is ideal for high-throughput (HTP) methods, when you have to grow multiple cultures expressing different proteins simultaneously

Features:
– No need to monitor cell growth
– No need for IPTG induction
– High cell densities (OD600 nm up to 14-20) and protein expression levels

Applications:
– Growing E. coli cells transformed with a IPTG-inducible bacterial vector
– Ideal for high-throughput (HTP) methods, when you have to grow multiple cultures expressing different proteins simultaneously

High levels of recombinant proteins produced using BL21(DE3) and BL21(DE3)pLysS E. coli strains as hosts
NZY Auto-Induction LB medium was tested for the production of 24 recombinant proteins from the anaerobic ruminal bacterium Ruminococcus flavefaciens in two expression E. coli strains, BL21(DE3) and BL21(DE3)pLysS, in parallel. For comparison, a competitor auto-induction medium was used following the manufacturer recommendations. Recombinant proteins were purified through Immobilized Methal Affinity Chromatography (IMAC) and separated by SDS-PAGE

For BL21(DE3) cells, in general the data revealed that NZYTech medium shows similar or higher levels of pure protein when compared with the competitor product. A detailed analysis of data collected shows that for 12 proteins in test, NZYTech auto-induction medium performed better than the competitor. Only one protein was shown to be produced at higher levels using the competitor auto-induction medium. For the remaining 10 proteins, the differences observed between media were not significant.

Figure 1. Levels of purified protein obtained from 24 different recombinant E. coli BL21(DE3) strains grown in NZY Auto-Induction LB medium (powder) or in a Competitor Auto-Induction medium. The 24 recombinant Ruminococcus flavefaciens proteins were purified through IMAC and levels of protein obtained evaluated (A) while the degree of purification was confirmed through SDS-PAGE (B). M: Protein Marker.

For BL21(DE3)pLysS cells, the tighter control of gene expression provided by the combination of the T7 lysozyme expressed by the pLysS plasmid ⁽¹⁾ and the lac repressor, encoded by lacI present in the protein expression system, ⁽²⁾ could explain the significant reduced protein expression upon induction for both the medium ^(3,4). Nevertheless, NZY Auto-Induction LB medium performed better for 15 proteins when compared with the competitor product.

Figure 2. Levels of purified protein obtained from 24 different recombinant E. coli BL21(DE3)pLysS strains grown in NZY Auto-Induction LB medium (powder) or in a Competitor Auto-Induction medium. The 24 recombinant Ruminococcus flavefaciens proteins were purified through IMAC and levels of protein obtained evaluated (A) while the degree of purification was confirmed through SDS-PAGE (B). M: Protein Marker.

Storage: Store dry at room temperature

^References:
⁽¹⁾ ^{Moffatt, B. A., &, & Studier, F. W. (1987). Cell, 49(2), 221–227}
⁽²⁾ ^{Dubendorf, J. W., & Studier, F. W. (1991). Journal of Molecular Biology, 219(1), 45–59}
⁽³⁾ ^{Studier, M. F. (1991). Journal of Molecular Biology, 219(1), 37–44}
⁽⁴⁾ ^{Pan, S. H., and Malcolm, B. A. (2000). BioTechniques, 29(6), 1–4}