Optimization Of Fermentation Conditions For Sugar Cane Molasses As Raw Material, Synthesis Of New Biomaterials Pha

Polyhydroxyalkanoates(PHAs) are introcellular polymers in bacteria. They can be classified into three categories'.﹕hort chain length (scl) PHAs, containing 4~5 carbon atoms in the monmers, especially PHB(polyhydroxybutyrate) ﹎edium chain length (mcl) PHAs, containing 6-16 carbon atoms in the monomers (3)PHAs containing monomer of sclHAs(hydroxyalkanoates) and mclHAs(hydroxyalka-noates).As one of the most interesting biodegradable materials, PHAs have a lot of promising applications in medicine, food science and agriculture.Concentration of cane molasses was found to be below 200g/L feasible for Pseudomonas pseudoalcaligenes YS1 to grow and produce PHAs.Three sections of one-way experiment were carried out to optimize concentration range of cane molasses, sodium octanoate and (NH^SO,, primarily. UC&*} orthogonal test was designed to optimize fermentation conditions including correlative carbon source (sodium octanoate,A), carbon source(cane molasses,B),nitrogen source ((NH<)2S04, C), and quantity of inoculation(D). Statistical analysis showed that PHA yield (g/L), cell dry weight (g/L) and PHA content (w/w%) suffered different effect from the four factors. To PHA yield (g/L), D>C>B>A, D3CiB2Aawas the optimal condition. To cell dry weight (g/L), D>A>C>B, D3A,C|B2was the optimal condition. To PHA content (w/w%), A>D>OB, AaDjCaBa was the optimal condition.Glucose was mixed with cane molasses to increase C/N molar ration to 50:1 and 100:1. It was found that maximum PHA yield (g/L), cell dry weight (g/L) and PHA content (w/w%) were 2.7249, 3.661 and 89.47%respectively.After all these optimization meassures, mixture of sclPHA& mclPHA yield was increased from 0. 0238g/L to 2.5724g/L, cell dry weight was increased from 1.6415g/L to 3.485g/L , PHA content was increased from 1. 446% to 73. 81%, whlie fermentation was changed from using cane molasses as sole carbon source to cane molasses80g/L, sodium octanoate 4g/L, glucose 9g/L.