The effect of oxygen on lipase production by Penicillium chrysogenum was studied under two operating modes, controlled aeration rate tested and controlled agitation at dissolved oxygen concentration (DO) 1.00 vvm. Lipase production and cell dry weight were tested in a stirred batch fermenter 5 L. Improvement in oxygen transfer rate (OTR) either by aeration or agitation resulted in an increase in lipase production. Growth curves and lipase activities of P.chrysogenum were examined at agitation rates (200,400,600 rpm), aeration rates (2,4 vvm) at different fermentation periods (24,48,72,96,120 h). Response Surface Methodology (RSM) using Design Expert software was used to study the effect of aeration, agitation, and fermentation time on lipase activity and cell dry weight. These factors were analyzed using 21. 32 level factorial design. An optimal set of conditions that maximize lipase production: (2 vvm aeration; 600 rpm agitation after 72 h) was obtained. The maximum lipase activity obtained was 240 U/mL. Beside lipase activity, this paper also studies the optimal combination of the controllable factors (aeration; agitation and fermentation time) that will maximize the cell dry weight.

PURPOSE: Revolutions have occurred over the last 3 decades in the management of patients with colorectal cancer. Most advances were in rectal cancer surgery, especially after the introduction of the total mesorectal excision (TME) by Heald. However, no parallel advances regarding colon cancer surgeries have occurred. In 2009, Hohenberger introduced a new concept trying to translate the survival advantages of TME to patients with colon cancer. This relatively new concept of a complete mesocolic excision (CME) with central vascular ligation (CVL) in the management of patients with colon cancer represents an evolution in operative technique. We performed a comparative study between CME with CVL and conventional surgery for patients with colon cancer at Italian and Egyptian cancer centers, considering surgical quality and clinical outcome. METHODS: Seventy-nine Egyptian patients underwent conventional surgery (non-CME group) while 52 Italian patients underwent CME with sharp dissection between the embryological planes and CVL of the supplying vessels (CME group). RESULTS: Significantly better results were observed in terms of lymph node yield (CME group: 22.5 vs. non-CME group: 12; P < 0.0001) and lymph node ratio (CME group: 0.03 vs. non-CME group: 0.22; P < 0.0001). Regarding surgical morbidity, no significant difference was noted (CME group: 2 vs. non-CME group: 5; P < 0.702). CONCLUSION: CME appears to be a safe procedure when performed by experienced hands through proper embryological planes. It also provides a superior specimen, with a higher lymph node yield, which consequently affects the lymph node ratio. Eventually, CME with CVL should be increasingly adopted and studied more deeply.
Colon* ; Colonic Neoplasms* ; Colorectal Neoplasms ; Hand ; Humans ; Ligation* ; Lymph Nodes ; Mesocolon ; Rectal Neoplasms