Study On The Biodegradation Of O-Nitrophenol By Lactobacillus Brevis LT-3

A strain of Lactobacillus brevis that can grow with o-Nitrophenol as the sole source of carbon and nitrogen was isolated from the activated sludge in the Chengdu waste water treat factory. The color of the strain's clone is creamy,the edge is smooth .The shape of the single Cells is pole ,about 0.5x 1 .Ojim large,without flagellum when inspected by light microscope and Electron Microscope. The cells of the strain were Gram-positive. The hydrogen peroxide reaction of the strain is negative.The strain can use ribose,glucose ,arabinose ,raffinose ,etc. According to the shape,physiological and biochemic character,it is identified as Lactobacillus brevis.According to the growth of the strain in the MMY biodegrading culture medium,it is able to bear about 0.15mM o-Nitrophenol,and able to grow in a wide range of temperature,the optimal temperature is about 30-3 7 ,above 40 ,there are floccule or grain appearing ,for some cells died. In different pH MMY biodegrading culture medium,the strain is able to grow at the rang of 6.0-8.0 ,the optimal pH is about 7.0.Using Rliodococcus erythropolis HL PM-1 as a positive control,the strainLbrevis LT-3 can degrade the o-Nitrophenol with a high efficiency. In laboratorial condition,Lbrevis LT-3 can degrade 86.7% of the o-Nitrophenol in the MMY biodegrading culture medium. But there is no -NO2 inspected by Griss reagent,both in the MMY biodegrading culture medium of the Rhodococcus erythropolis and the Lbrevis.After the MMY biodegrading culture medium of the Lbrevis has been cultured for 6> 8x 10 hours,it was inspected using UV-visible light spectrometer,scaned by ultraviolet light The results of the UV-spectra indicated that the absorb of the MMY biodegrading culture medium decreased in the range of the 205-220 run and 260-300 nm. The MMY biodegrading culture medium of the Lbrevis has been cultured for 10 hours,then was extracted by aceticethanol and analyzed by Mass spectra,me analytical results indicated there is new mass produced about bigger 74D than the o-Nitrophenol.This experiment is a benefit explore in the study of biodegradation of the nitroaryl compound. The Strain Lbrevis is a new bacteria strain which is able to biodegrade o-Nitrophenol. But the metabolize route of this strain degrading o-Nitrophenol is need to be study more.