Amicon ultra 10 000 nmwl

Isolation and characterization of thermophilic lipaseproducing bacteria. Samples were collected from a hightemperature aerobic fermentation reactor system. After enriching five times in 1¥nutrient broth medium (0.5% peptone and 0.3% yeast extract, Difco/BD Diagnostics, Sparks, MD, USA) at 50∞C with shaking at 200 r.p.m., clear halo-forming colonies were isolated by repeatedly streaking on 1.5% (w/v) agar plates containing 0.5% (v/ v) tributyrin at 50∞C. Genomic DNA was extracted using a DNA purification kit (Promega, Madison, WI, USA). 16S rRNA gene sequences were amplified and determined using universal primers for bacteria (27F, 515R, and 1562R) (Weisburg et al., 1991) . The 16S rRNA sequences of NB501 and NB502 were submitted to DDBJ with accession numbers LC144539 and LC144540, respectively.
Preparation of native extracellular lipase. NB501 was cultivated in 200 mL of 1¥nutrient broth medium (0.5% peptone and 0.3% yeast extract, Difco) supplemented with 2% (v/v) used cooking soybean oil at 50∞C with shaking at 200 r.p.m., The culture broth was collected and concentrated using an ultrafiltration membrane (Amicon Ultra 10,000 NMWL, Merck Millipore, Darmstadt, Germany).