Table 4 Bacillus-derived organic acids, exoenzymes and other metabolites that involved in bacteria to host interaction

Organic acids

Acetate

B. subtilis

B. coagulans

B. clausii

Pathogens inhibition and coordinate the formation of biofilm

[154,155,156]

Butyrate

B. clausii

B. subtilis

Host metabolic improvement

[157]

Indoleacetic acid

B. amyloliquefaciens

Growth promotion

[158]

Lactate

B. coagulans

B. subtilis

Intestinal barrier recovery and microbiota modulation

[137, 159]

Propionate

B. thermoamylovorans

B. clausii

Enhance the efficacy of antibiotic and host immunity modulation

[154, 160, 161]

Tryptophan

B. subtilis

Host immunity modulation

[162]

Exoenzymes

Amylases

B. lichenformis

B. cereus

Bacterial adaption, nutrient digestibility and intestinal health improvement

[163, 164]

Cellulases

Bacillus sp.

Improving digestive of cellulose-like nutrients

[165]

Chitinase, Chitosanase

B. subtilis

Antifungal activity and chitin degradation

[166]

Fibrinolytic enzymes

B. subtilis

Treatment of cardiovascular

[167]

Lipase

B. flexus

Inhibit pathogen’s biofilm formation

[168]

Lysozyme

B. pumilus

Antibacterial activity

[169]

Nattokinase

B. subtilis

Cardiovascular health improvement

[170, 171]

Phytase

B. licheniformis

Enhance nutrient availability

[172, 173]

Protease

B. licheniformis

B. proteolyticus

B. clausii

Nutrient digestibility improvement, antimicrobial activity, and toxin degradation

[174,175,176]

Other metabolites

CSF

B. megaterium

Controls competence and spore formation

[177]

ComX pheromone

B. licheniformis

Antifungal activity

[178]

ESP

B. subtilis

Suppress inflammatory response, maintain intestinal barrier, and reduce pathogen’s adhesion

[179, 180]

NAD

B. subtilis

Microbiota modulation and boost host NAD metabolism

[181, 182]

Spermidine

B. subtilis

Improve gut barrier integrity and gut microbiota function

[183, 184]

Vitamin B6

B. subtilis

Accelerate pathogen’s clearance

[185]

Vitamin B12

B. megaterium

Affecting DNA synthesis and regulation, fatty acid synthesis and energy production

[186, 187]

Vitamin K

B. subtilis

Prevention of osteoporosis and cardiovascular disease

[188,189,190]