tryptophan auxotroph isolated after X-ray mutagenesis of B. subtilis Marburg strain and is widely used in research due to its high transformation efficiency. Bacillus globigii, a closely related but phylogenetically distinct species now known as Bacillus atrophaeus was used as a biowarfare simulant during Project SHAD (aka Project 112). Subsequent genomic analysis showed that the strains used in those studies were products of deliberate enrichment for strains that exhibited abnormally high rates of sporulation. A strain of B. subtilis formerly known as Bacillus natto is used in the commercial production of the Japanese food nattō, as well as the similar Korean food cheonggukjang. 21st century As a model organism, B. subtilis is commonly used in laboratory studies directed at discovering the fundamental properties and characteristics of Gram-positive spore-forming bacteria. In particular, the basic principles and mechanisms underlying formation of the durable endospore have been deduced from studies of spore formation in B. subtilis. Its surface-binding properties play a role in safe radionuclide waste [e.g. thorium (IV) and plutonium (IV)] disposal. Due to its excellent fermentation properties, with high product yields (20 to 25 gram per litre) it is used to produce various enzymes, such as amylase and proteases. B. subtilis is used as a soil inoculant in horticulture and agriculture. It may provide some benefit to saffron growers by speeding corm growth and increasing stigma biomass yield. It is used as an "indicator organism" during gas sterilization procedures, to ensure a sterilization cycle has completed successfully. This is due to the difficulty in sterilizing endospores. B. subtilis has been found to act as a useful bioproduct fungicide that prevents the growth of Monilinia vaccinii-corymbosi, a.k.a. the mummy berry fungus, without interfering with pollination or fruit qualities. Both metabolically active and non-metabolically active B. subtilis cells have been shown to reduce gold (III) to gold (I) and gold (0) when oxygen is present. This biotic reduction plays a role in gold cycling in geological systems and could potentially be used to recover solid gold from said systems. Novel and artificial substrains Novel strains of B. subtilis that could use 4-fluorotryptophan (4FTrp) but not canonical tryptophan (Trp) for propagation were isolated. As Trp is only coded by a single codon, there is evidence that Trp can be displaced by 4FTrp in the genetic code. The experiments showed that the canonical genetic code can be mutable. Recombinant strains pBE2C1 and pBE2C1AB were used