Bacillus subtilis Biosensor Engineered To Assess Meat Spoilage

Abstract

Here, we developed a cell-based biosensor that can assess meat freshness using the Gram-positive model bacterium Bacillus subtilis as a chassis. Using transcriptome analysis, we identified promoters that are specifically activated by volatiles released from spoiled meat. The most strongly activated promoter was PsboA, which drives expression of the genes required for the bacteriocin subtilosin. Next, we created a novel BioBrick compatible integration plasmid for B. subtilis and cloned PsboA as a BioBrick in front of the gene encoding the chromoprotein amilGFP inside this vector. We show that the newly identified promoter could efficiently drive fluorescent protein production in B. subtilis in response to spoiled meat and thus can be used as a biosensor to detect meat spoilage.

Engineering a palette of eukaryotic chromoproteins for bacterial synthetic biology

“…Current methods for detecting environmental, agricultural and food contaminants, landmines and biowarfare agents, and medically-relevant targets can be improved by synthetic biology [ 10 ]. For example, bacteriophage have been engineered to cause bioluminescence of pathogenic bacteria in food, and bacteria have been engineered to fluoresce upon detection of spoiled meat gas [ 11 ], trinitrotoluene (TNT) products [ 12 ] or arsenic [ 13 ]. Adaptation of these biosensors to non-fluorescent detection for use in supermarkets or the field beckons, but it is unclear which CP genes might be suitable or how best to assay them quantitatively.…”

Time‐Temperature Indicator Based on Enzymatic Degradation of Dye‐Loaded Polyhydroxybutyrate

“…Among these, bio‐chemical TTIs have the most suitable kinetics for monitoring fresh food products, as both bacterial and enzymatic activity are good markers of microbial growth, food degradation processes, and, thus, of the resulting loss in quality. The literature shows interesting implementations of bacterial TTIs, where a bacterial culture is grown inside the TTI, and the changes in the pH/chemical composition are used to indicate the loss of quality. However, bacterial TTIs have practical difficulties in manufacturing, handling and safety that make them unsuitable for food products.…”

In-vivo identification and control of aerotaxis in Bacillus subtilis

“…as biosensor for food spoilage detection [4]. Given these characteristics (a strong aerotactic response combined with adaptability to heterogeneous environmental conditions) and the potential uses of this microorganism in industrial biotechnology and synthetic biology, we have selected it as model system for our experiments.…”