Solid state culture of Streptomyces lydicus to produce antimicrobial substance

• Main Authors: Hao-yu Lin, 林皓羽
• Other Authors: Kow-Jen Duan
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/gmk4bf

碩士 === 大同大學 === 生物工程學系(所) === 102 === Actinomycetes, particularly Streptomyces spp. are a group of microorganisms that have been widely exploited in the production of secondary metabolites (antibiotics) and enzymes of commercial importance in medical and agricultural applications. It is estimated 50 % of antibiotics in the market are made from Streptomyces sps. They can be used in healthcare for human beings or animals, feed additives, biocontrol agents in vegetable or fruit cultivation. Solid state fermentation of Streptomyces sps is particularly useful in agriculture. The fixed cost is low, and many agriculture wastes can be used as medium. Furthermore, nutrient residue in the medium is fertile to the plant. After fermentation by Streptomyces sps, the solid medium with antibiotics, spores and chitinase can be mixed with soil to protect plant against pathogens of plants. In this investigation, we employed a newly isolated S. lydicus to produce antibiotics using solid state fermentation. The bacteria showed antifungal activity against several plant pathogens. We found out that oat flake was the best medium for solid state fermentation to produce antibiotic activity compared with oat, barley flake, barley, or brown rice. Furthermore, the oat flake supplemented with chitin achieved the best antibiotic activity after cultivation. There was no positive effect in antibiotic activity for the oat flake supplemented with nitrogen IV source such as yeast extract, peptone, or defatted soybean meal, cotton seed. Sporulation of the solid state culture started from the 3rd day after inoculation. Oat flake supplemented with 1% glucose achieved the most spore production, 3.6 x109 CFU/g-medium after cultivation of 16 days from 4.3 x106 CFU/g-medium at inoculation. There was no positive effect of nitrogen source to increase spore formation of the solid state cultivation of S. lydicus.