Bacillus thuringiensis production

Commercial Prospects. From the point of view of commercial exploitation, biopesticide sales in 1990 were estimated at 120 million, representing less than 0.5% of tlie world agrochemical market. Over 90% of sales are accounted for by Bacillus thuringiensis products. However, sales are estimated to be increasing at 10-25% per annum while the world agrochemical market remains static (Rodgers unpublished data, presented at Society of Chemical Industry Symposium, London, UK, December 1992). 

Mackowiack P.A. (1979) Clinical uses of microorganisms and their products, JMed, 67,293-306. Priest EG. (1992) Biological control of mosquitoes and other biting flies hy Bacillus sphaericus and Bacillus thuringiensis. J Appl Bacterial, 72, 357-369. 

The key insect-specific bacterium is Bacillus thuringiensis and this is through the production of delta-endotoxins. It has been shown that if the endotoxins are applied to crops together with living spores of the bacterium, insect control is improved. It is common for living formulations to be sold. 

L.F. Adams, C.-L. Liu, S.C. Macintosh and R.L. Starnes, Diversity and Biological Activity of Bacillus thuringiensis, in Crop Protection Agents from Nature natural products and analogues , ed. L.G. Copping, Royal Society of Chemistry, Cambridge UK, 1996, pp. 360-389. 

Grafting a microbial oxidation of L-Srb into 2KLG on the Reichstein process, which is an obvious improvement to the latter, results in a two-stage fermentative process (Fig. 8.30a). China was the first country to develop [155] and universally adopt such a process [156]. Its production costs are said to be 30% lower that those of the traditional process [157]. Cerestar has claimed an 89% yield (100 g I.1 STY 78 g IT1 d ) of 2KLG from L-Srb in a mixed culture of G. oxy-dans and Bacillus thuringiensis [151]. Such processes have now been introduced in Europe, for example by KGS (Krefeld, Germany) and DSM (Dairy, Scotland). 

Figure 1. SDS-PAGG analysis of alkaline-dissolved Bacillus thuringiensis subspecies kurstaki (BTK) and israelensis (BTI) -endotoxin at 25 yg per track (1) BTK -endotoxin from Biochem Products - US Division (Salsbury Labs., Inc.), (2) BTI 6-endotoxin from Sandoz Inc., (3) BTI (Sandoz) -endotoxin purified by DEAE-anion exchange chromatography, (4) percipitate formed after dialysis of BTI (Sandoz) -endotoxin into pH 4.5 sodium acetate buffer, (5) soluble fraction after dialysis of BTI (Sandoz) -endotoxin into pH 4.5 sodium acetate buffer, (6) BTI (Sandoz) -endotoxin purified by Sephadex G-75 gel filtration chromatography at Rf 1.35, (7) at Rf 1.58, and (8) BTI strain IFC-1 -endotoxin from Biochem Products - US Division (Salsbury Labs., Inc.). S, molecular weights as indicated X1000 for bovine serum albumin (BSA), ovalbumin (OA), trypsin, and myoglobin. Reproduced with permission from Ref. 29. Copyright 1984, Academic Press, Inc.

Bacillus thuringiensis Berliner (commonly known as Bt) is an insecticidal bacterium discovered in the early 20th century. The commercial Bt products are powders containing a mixture of dried spores and crystalline 8-endotoxin, but some contain only the toxin component. Both spores and toxin crystals are produced within the bacterial vegetative cell by Bt (Figure 4.12). Currently, there are six strains that possess specific activity against different insect species as follows ... 

Several strains of the Bacillus thuringiensis are pathogenic to some insects. The bacterial organisms are cultured, then harvested in spore form for use as insecticide. Production methods vary widely. Proteinaceous and nu-cleotide-like toxins generated by the vegetative forms (which infect insects) are responsible for the insecticidal effect. The spores are formulated as wettable powders, flowable concentrates and granules for application to field crops and for control of mosquitoes and black flies. 

Table 5.6 Commercial Products containing Bacillus thuringiensis.

Strains isolated from commercial products (supposed to containing Bacillus thuringiensis and used as organic pesticides by farmers) in the Laboratory of Bacteriology (Toulouse, France), and identified on the basis of parasporal crystal ceU inlusions presenceisolates from commercial preparations of biopesticides... 

Fig. 2 PCR products digested by Hinfl endonuclease. Lane 1 B. thuringiensis DSMZ 2046 Lane 2 B. thuringiensis from coffee Lane 3 Bacillus thuringiensis DSMZ 350 Lane 4 Bacillus cereus DSMZ 4282 Lane 5 B. cereus from licotta Lane 6 B. cereus DSMZ 2301 Lane 7 uncut PCR product B. cereus DSMZ 2301 Lane 8 Molecular Weight Marker, (Sigma, Milan, Italy)...

Biological insecticides Bacillus thuringiensis kurstakii, 1902 (products 1938) 10-40 (5 - 20 x 109 IU) III Narrow... 

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