Benefits and Applications

The genome of Bacillus licheniformis DSM13 is very well studied consisting of a single
chromosome that has a size of 4,222,748 base pairs. The average G+C ratio is 46.2%.
4,286 open reading frames, 72 tRNA genes, 7 rRNA operons and 20 transposase genes
were identified. The genome contains defined inserted regions that can be identified at
the sequence as well as at the functional level. B. licheniformis DSM13 has a
well-conserved secretory system, no polyketide biosynthesis, but is able to form the
lipopeptide lichenysin. From the further analysis of the genome sequence, we identified
conserved regulatory DNA motives, the occurrence of the glyoxylate bypass and the
presence of anaerobic ribonucleotide reductase explaining that B. licheniformis is able to
grow on acetate and 2,3-butanediol as well as anaerobically on glucose. This makes
Bacillus licheniformis a key organism in industrial biotech for easy maintenance and
genetic manipulation.
Bacillus licheniformis is a Gram positive spore-forming bacterial species of high
biotechnological interest with numerous present and potential uses, including the
production of bioactive compounds that are applied in a wide range of fields, such as
aquaculture, agriculture, food, biomedicine, and pharmaceutical industries.
Cellulase enzymes are applied in juice extraction processes, pulp and paper, textile
industry, secondary metabolites, animal feed, extraction of vegetable dyes and in
obtaining fermentable sugars used in the production of biofuels, and the demand for this
enzyme is exponentially increasing
Its use as an expression vector for the production of enzymes and other bioproducts is
also gaining interest due to the availability of novel genetic manipulation tools with
applications in bioflocculation, biomineralization, biofuel production, bioremediation, and
anti-biofilm activity.
B. licheniformis is used as a probiotic in animal feed, where isolates have been shown to
prevent disease and promote growth.
It also has agricultural applications by preventing and controlling certain plant diseases,
soil improvement, and fertilizer efficiency.
Two main products directly associated with B. licheniformis are -
- Bacitracin -
  A mixture of peptides produced by Bacillus licheniformis. Bacitracin A is the
  major constituent of commercial preparations. It has been widely used as a
  growth promoter in animals, but has been banned for that purpose in the
  European Union.
  It is highly active against many Gram-positive bacteria and is mainly used as a
  component of topical preparations.
- Lichenysin -
  Lichenysin is a surfactin-like LP produced by Bacillus licheniformis. The molecule
  exhibits structural and functional similarities with the surfactin class of LPs.
  Stability over a wide pH range, temperature, and salt concentration. Hence B.
  licheniformis is used in laundry detergent formulations.

Maintenance

Bacterial isolates are also cultured in MBS medium (30 °C, 500 rpm, for up to five days)
to evaluate their ability to form spores. Fresh mounts are immobilized on agar pads (3%
aqueous agar solution) and prepared using an aliquot of the culture.
The strain is preserved in the form of spores impregnated in paper discs. Initially, the
microorganism is grown in MBS broth sporulation medium (composition, in g/L: meat
peptone 10.0; yeast extract 1.0; KH2PO4 1.0; MgSO4.7H2O 0.1; CaCl2.2H2O 0.1 ;
FeSO4.7H2O 0.01; MnSO4.H2O 0.01; ZnSO4.7H2O 0.01), pH 7.2, in a shaker at 200
rpm, 30 °C for 5 days.
A volume of 30 mL of the culture is centrifuged at 6000 rpm for 20 minutes and the
supernatant is discarded. Then, the sample is resuspended in 3 mL of a saline solution
(NaCl 0.85% w/v), incubated at 80 °C for 12 minutes, and subsequently immersed in an
ice bath for 5 minutes. For spore quantification, serial decimal dilutions of the cell
suspension in a saline solution (NaCl 0.85% w/v) are made, and a 100-μL aliquot is
evenly distributed over Petri dishes containing nutrient agar medium using a spreader.
Plates are incubated for 48 hours at 30 °C until bacterial colonies are visually observed,
and the results are expressed in spores mL−1.
Blotting paper weighing 250 g m−2 and a 7.0 mm hole punch are used to prepare the
discs. Twenty discs are distributed per Petri dish (90 × 15 mm), which are individually
packed, autoclaved at 121 °C in three 1-hour cycles with 24-hour intervals, and then
oven-dried at 60 °C.
After the sterilization and drying process, discs are impregnated with 20 μL aliquots of
the cell suspension (5.8 × 10^9 spores mL−1), dried in an oven at 35 °C for 24 hours,
and stored in a refrigerator at 4 °C.
The optimal conditions are determined to be a cultivation temperature of 50-60°C with 12
hours of cultivation time at an agitation speed of 100 rpm and an inoculum size of 1.7 ×
10^9 cells/ml. Enzyme production is maximum between 45-50°C.

Genome

Bacillus licheniformis - https://www.ncbi.nlm.nih.gov/datasets/taxonomy/1402/