解钾菌的分离筛选及其解钾能力测定

Isolation of Potassium Bacteria and Determination of Potassium Dissolving Ability

采集农作物、蔬菜、梨树等根际土样,采用以钾长石为唯一钾源的亚历山鲍罗夫培养基分离筛选解钾菌。根据解钾圈大小,从梨树、蚕豆、豌豆、黄豆根际土壤中初步筛选得到9株解钾菌,将这9株解钾菌接种解钾液体培养基,培养后,采用火焰光度计法测定速效钾含量。发酵液中有效钾含量最高为13.5 mg/L,比对照组增加了11.98 mg/L。通过单因素试验,确定菌株生长的最适碳源是蔗糖,最适氮源是蛋白胨,初始p H值6.5;最适的培养条件为摇床转速为160 r/min,培养温度为25℃,培养7 d,初始OD值为0.02,装液量为80 m L/250 m L。在这些适宜培养条件下,菌株的菌体密度提高了45%。

In order to isolate efficient potassium bacteria,rhizospher soil samples of the crop,pear trees and vegetables were collected. Potassium bacteria were isolated and screened out by Aleksandrov medium which uses potash feldspar as the sole potassium source. According to the yellow halo zones,nine potassium bacteria strains were separated from the soil samples of the pear,broad bean,pea and soybean root,respectively,Then,the bacteria were inoculated into Aleksandrov liquid medium and cultivated. The content of available potassium was determined by flame spectrophotometry. The available potassium content was the highest at 13. 50 mg/L which was 11. 98 mg/L higher than that in the control group. Single factor tests were adopted to determine the optimal medium for growth of the strain of JK-1. The optimal carbon source was sucrose,the optimal nitrogen source was peptone,and the initial p H was 6. 5. The optimal culture conditions were as follows： the rotational speed of the shaker was 160 r/min,the optimal temperature was 25 ℃,the initial OD value was 0. 02,the volume of liquid was 80 m L in 250 m L shake flask. Under these optimal conditions,cell density of JK-1 was increased by 45%.