Study On Mytilus Sp.Shell Preparing Organic Calcium By Acetobacter Aceti Fermentation

Mytilus sp.shell as a valuable resource was abundant on the beach and polluted the coastal ecological environment.In order to make better use of this waste resource,shell powder was been fermented by acetic bacteria and been converted into organic calcium which can absorb more easily by human.In this thesis,the author studied optimal conditions of fermentation and fed-batch fermentation to enhance the conversion rate of the shell's calcium,and compared the characterize of calcium acetate both obtained by fermentation or reaction with acetic acid.1.Studied the optimal conditions of fermentation showed that:the synthetic medium has more strong capacity of production acid and conversion calcium,and the synthetic medium's composition was simple which can be easier to separate and purify for production;compared with different speeds found that the acetic bacteria has more strong capacity of production acid and conversion calcium when the speeds was 200 r/min;compared with different shell powder addition found that there was little affect,comprehensive consider chosen 20%of shell powder addition;compared with different initial alcohol concentrations found that the initial alcohol concentrations of 6%(v/v)gained the better rate of acetic acid synthesis and growth rate of acetic bacteria.2.Studied the different affect of batch fermentation and fed-batch fermentation on calcium biotransformation of mussel shell.The results showed that:inhibit of cell growth due by inadequate nutrition of substrate can been compensate by fed-batch fermentation.In addition,the fed-batch fermentation can make the maximum synthesis of the target product and promote the maximization of the transformation of calcium.Comparing with batch fermentation,the calcium concentration of fed-batch fermentation was increased from 16.96mg/mL to 33.99mg/mL.3.Studied the 5L fermenter tank batch fermentation,the results showed that the fermentation efficiency can been improved three times compared with shake flask fermentation,but the final calcium concentration was 19.91 mg/mL which lower than the shake flask's fed-batch fermentation.So finally the fermenter tank's fermentation process should been optimized.4.Two calcium acetate samples(obtained by fermentation or reaction with acetic acid)were been determined by scanning electron microscopy(SEM)and Fourier transform infrared spectrometer(FT-IR).The SEM's results showed that the calcium acetate sample obtained by fermentation has closer texture and more slender crystal.And the FT-IR also confirmed the SEM's results,while there was no difference of these two kinds of calcium acetate on the coordination mode between carboxylic acid and metal ions,both were bridge coordination way.Compared with the solubility of this two sample can found that the calcium acetate obtained from fermentation has better solubility.