Document Type : Original Article
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Abstract
Whey with a large amount of BOD(50000 PPM) is a dangerous environmental pollutant.this important source of lavtose(4-5%) is A USEFULL SUBSTRATE FOR A RANGE of fermentation processes.lacitic acid with swvwral applications in industries is one of these products.Specially L(+) isomer of this acid worthing 10 times as much as the mixture of L&D,is used in medical purposes such as absorbable surgical filaments and controlled release drugs.several strains of lactobacillus produce a mixture of L&D isomers but the strain employed in this research(lactobacillus casei)produces only L(+) form.the prodices lactic acid prevents acid production in fermentation,so that almost half of lactose (about 22 g/l lactic acid) is converted to lactic acid.therefore in order to increase the output the produced acid should be separated.in this research lactobacillus casei was used to produce L(+) lactic acid and due to strile conditions requirement in situe separation of acid using Ion-exchange resins at control automatic of Ph were employed.at the end,lactic acid yield in non extractive fermentation compared with extractive process showed an increase from 22g/l to 43.7g/l.the polarimetric analysis showed pure L(+) product.
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