Lactococcus lactis (MG1363)
Food-grade, GRAS lactic acid bacterium used for centuries in dairy fermentation. Non-colonizing and ideal for ingestible / clinical biosensors where a food-safe, gut-transient host is wanted.
Identity
- Species
- Lactococcus lactis
- Strain
- MG1363
- NCBI taxid
- 416870
- Genome
- NC_009004.1
Safety
- Biosafety level
- BSL-1
- Pathogenic
- No
- GRAS
- Yes — FDA GRAS for food use; EFSA QPS; centuries of safe use in dairy.
- Probiotic
- Yes — Food fermentation; engineered L. lactis trialed clinically (e.g. mucosal delivery).
- Biocontainment
- thyA-based biological containment demonstrated in clinical trials (transient survival).
- BSL-1 basis
- ABSA Risk Group 1; FDA GRAS; EFSA QPS.
Gram-positive, no LPS endotoxin; transient gut passage (does not colonize).
Traits
- Gram
- positive
- Oxygen
- facultative
- Optimal temp
- 30 °C
- Doubling time
- ~60 min
- Spore-forming
- No
- Transformable
- Yes
Engineering
- CRISPR tooling
- dCas9/CRISPRi demonstrated in lactic acid bacteria.
- Common promoters
- PnisA (nisin-inducible, NICE system), P32 (constitutive)
- Selection markers
- ErmR, CmR
- Toolkits
- NICE (nisin-controlled expression), SEVA-compatible vectors
Biosensors using this chassis
Fluoride sensor (riboswitch + CRISPRa)
Detects fluoride in drinking water using a natural fluoride riboswitch as the sensor, gating a CRISPRa circuit driving a fluorescent reporter, in the food-grade GRAS chassis Lactococcus lactis.
Gut acid/pH sensor (GadE + CRISPRa)
Reports gut acidity / low pH (linked to short-chain-fatty-acid load and dysbiosis). The acid-responsive Gad system gates a CRISPRa circuit driving a fluorescent reporter, in the food-grade acid-tolerant chassis Lactococcus lactis.
Lactate sensor (LldR + CRISPRi)
Detects L-lactate, a fermentation and clinical metabolite. The LldR lactate-responsive regulator gates a CRISPRa circuit driving a fluorescent reporter, in the food-grade GRAS chassis Lactococcus lactis.
Naringenin/flavonoid sensor (FdeR + CRISPRa)
Detects naringenin and related flavonoids (dietary and nutraceutical compounds). The Marionette FdeR sensor gates a CRISPRa circuit driving a fluorescent reporter, in the food-grade GRAS chassis Lactococcus lactis.
Streptococcus sensor (CSP/ComD + CRISPRa)
Detects Streptococcus via its competence-stimulating peptide (CSP). The ComD/ComE quorum system gates a CRISPRa circuit driving a fluorescent reporter, in the food-grade Gram-positive chassis Lactococcus lactis.
Tryptophan sensor (TrpR + CRISPRi)
Detects tryptophan, a dietary amino acid and precursor of gut-microbial indole/serotonin metabolites. The classic TrpR repressor gates a CRISPRi circuit driving a fluorescent reporter, in the food-grade GRAS chassis Lactococcus lactis.
Zinc sensor (ZitR + CRISPRi)
Detects zinc, a nutritional and water-quality marker. The native L. lactis ZitR zinc regulator gates a CRISPRi circuit driving a fluorescent reporter, in the food-grade GRAS chassis Lactococcus lactis.