Microorganisms polylactides

Polylactides are made from lactic acid and are used for orthopedic repair materials. They can be absorbed by the body and are used for the treatment of porous bone fractures and joint reconstruction. Dextran is a substitute for blood plasma in medicine. It is produced by fermentation of saccharose by Leuconostoc mesenteroides microorganisms. After the fermentation is completed (about 24 h), the cell mass is separated and the dextran is precipitated by addition of ethanol to the liquid phase. 

Hakarainen, M., Karlsson, S. and Albertsson, A.C. (2000) Rapid (bio)degradation of polylactide by mixed culture of compost microorganisms-low molecular weight products and matrix changes. Polymer, 41,2331-2338. 

Biodegradable polymers are polymers that can be degraded by microorganisms such as bacteria, fungi, or algae. Polylactide (PLA), a biodegradable polymer of lactic acid, has found wide use. When lactic acid is polymerized, a molecule of water is lost that can hydrolyze the new ester bond. 

Polylactides are linear polymers obtained from lactic acid, CHjCHOHCOOH, commonly known as poly(lactic acid) or polylactide. Lactic acid occurs naturally in animals and microorganisms and is found in many natural foods especially in fermented foods such as yogurt, buttermilk, sourdough breads, and sauerkraut [90, 91]. Besides being biodegradable, bioresorbable, and biocompatible, PLAs can be easily conformed by conventional thermoplastic melt processing, which makes this class of biodegradable polymers very suitable for uses in bionanocomposites. 

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