Biosurfactants were synthesized by Pseudomonas aeruginosa （P.A.）, using sugar cane molasses as carbon source. Assays were conducted in a shaker with agitation speed of 200 rpm, temperature of 38 ℃ and aeration rat...Biosurfactants were synthesized by Pseudomonas aeruginosa （P.A.）, using sugar cane molasses as carbon source. Assays were conducted in a shaker with agitation speed of 200 rpm, temperature of 38 ℃ and aeration ratio （Vm/Vf） of 0.4 and 0.6. A concentration of 3.0% was used for the carbon and energy source （molasses） and of 0.3% for the nitrogen source （NaNO3）. Samples were removed at regular times until 96 hours of cultivation. The reduction in surface tension was measured using the ring method; cell concentration was obtained by the dry mass and substrate consumption by the DNS method. The metabolite produced was extracted and quantified by the thioglycolic method. The results showed a maximum surface tension reduction of 46.57% after 60 h, 3.63 g/L of biomass after 8 h （μXmax =0.15 h^-1）, 79.60% of substrate consumption （μs= 0.67 h-1） and 4.47 g/L of rhamnolipid （μp=0.029 h^-1）.展开更多
每周的手工课总是让人充满期待,看着自己亲手制作出来的手工品,不管结果如何,心中总是充满成就感。还要记得把自己的作品拿回家,给家人展示一番哦。但是小朋友,你知道吗?在手工课上,有一些工具是很危险的,例如:刀片、剪刀等,常常一不小...每周的手工课总是让人充满期待,看着自己亲手制作出来的手工品,不管结果如何,心中总是充满成就感。还要记得把自己的作品拿回家,给家人展示一番哦。但是小朋友,你知道吗?在手工课上,有一些工具是很危险的,例如:刀片、剪刀等,常常一不小心就会“hurt the finger”。如果看见同学受伤,就可以用“What happened?”来询问状况并表示自己的关心,同时也别忘了说“Be careful!”来互相提醒,注意手工操作时的安全哟!展开更多
文摘Biosurfactants were synthesized by Pseudomonas aeruginosa （P.A.）, using sugar cane molasses as carbon source. Assays were conducted in a shaker with agitation speed of 200 rpm, temperature of 38 ℃ and aeration ratio （Vm/Vf） of 0.4 and 0.6. A concentration of 3.0% was used for the carbon and energy source （molasses） and of 0.3% for the nitrogen source （NaNO3）. Samples were removed at regular times until 96 hours of cultivation. The reduction in surface tension was measured using the ring method; cell concentration was obtained by the dry mass and substrate consumption by the DNS method. The metabolite produced was extracted and quantified by the thioglycolic method. The results showed a maximum surface tension reduction of 46.57% after 60 h, 3.63 g/L of biomass after 8 h （μXmax =0.15 h^-1）, 79.60% of substrate consumption （μs= 0.67 h-1） and 4.47 g/L of rhamnolipid （μp=0.029 h^-1）.
文摘每周的手工课总是让人充满期待,看着自己亲手制作出来的手工品,不管结果如何,心中总是充满成就感。还要记得把自己的作品拿回家,给家人展示一番哦。但是小朋友,你知道吗?在手工课上,有一些工具是很危险的,例如:刀片、剪刀等,常常一不小心就会“hurt the finger”。如果看见同学受伤,就可以用“What happened?”来询问状况并表示自己的关心,同时也别忘了说“Be careful!”来互相提醒,注意手工操作时的安全哟!
