PRODUCTION OF MICROBIAL ALGINATE

Abstract

In view of its commercial importance, recent attempts are being made on various aspects for alginate production by bacteria. The aim of the present study is to optimize culture conditions of Azotobacter vine landii for maximum alginate production and isolate genetically improved mutant capable of producing high quantities of alginate. 1- The organism was grown on five different media to test their suitability for alginate production. Best yield was obtained with JARMAN medium of the following composition (g/l) Sucrose, 20; MgS0,.7H,0, 0.2; Nac1, 0.2; Cacl, .2H,0, 0.042; KH,PO,, 0.008; K,HPO,, 0.032; Fes0,.TH,0, 0.003; H,BO0,,0.0029; Zns0,.7H,0, 0.0012; Na,1Mo0.2H,0, 0.001; CuSO,.5H,0, 0.0001 and MnCl,. 4H,0, 0.0009 (Jarman et al, 1978), and of a reaction adjusted to give initial pH 7.

2- Sucrose was selected as the best carbon and energy source among six different carbon sources tested. Maximal value of alginate formed was achieved at sucrose level of 40 g/l. 3- The viscosity and alginate yield of the culture filtrate were also affected by the size of inoculum and age of seed culture. Best results were obtained using 5% inoculum size of a 36 h old seed culture. 4- The fermentation activities were tested using a medium of initially adjusted reaction. Best alginate yield was achieved with the fermentation medium initially adjusted to pH 8.0.