Effects of abiotic factors on production of Levan by microorganisms: A review
Anu Bansal, Khushboo Singh, Arun Karnwal
Levan biopolymer is an exopolysaccharide (EPS) produced by several plant species and micro-organisms. Levan produced from the plant is of low molecular weight ranging from about 2000 to 33,000 Da and those produced from microorganisms is of high molecular weight ranging from 2 to 100 million Da. Levan produced from microorganisms is of high yield depending on the provided substrate. Therefore, levan produced from microorganisms is widely used in industrial applications. Levansucrase is the key enzyme catalyzing the production of levan from the sucrose. Many bacterial species of Bacillus, Pseudomonas, Rhizobium consists of Levansucrase. The synthesis of levansucrase is dependent on the culture media for the growth of microorganism. Thereby, levan production is affected by type and amount of carbon source, temperature and pH. Optimum temperature for levan production by microorganisms ranges from 37oC to 45oC while temperature above 47oC decreases the levan production and optimum pH is 6-7. The levan produced by microorganisms at optimum conditions have various applications in food, cosmetic, pharmaceutical industries.