High-concentration nitrogen removal coupling with bioelectric power generation by a self-sustaining algal-bacterial biocathode photo-bioelectrochemical system under daily light/dark cycle.

High-concentration nitrogen removal coupled with bioelectric power generation in an algal-bacterial biocathode photo-bioelectrochemical system (PBES) was investigated. The PBES can self-sustaining operation with continuous power output under day/night cycle by alternately using photosynthetic dissolved oxygen and nitrate/nitrite as cathodic electron acceptors. The PBES generated a high maximum power of 110mw/m2 under illumination and relatively lower power of 40mw/m2 under dark. The bioelectricity generation was accompanied by high-concentration nitrogen removal in the algal-bacterial biocathode. The NH4N was removed completely within 120 h while maximum NO3N removal efficiency of 86% and maximum total nitrogen removal efficiency of 83% can be reached after 192 h at initial NH4N concentration of 314 mg/L and NO3N concentration of 330 mg/L. Combined processes of bioelectrochemical reduction and algal-bacterial interactions provided multiple approaches for nitrogen removal in the biocathode, including nitrifying using photosynthetic oxygen, bioelectrochemical denitrification using the cathode as electron donor, heterotrophic denitrification using photosynthetically produced dissolved organic matters as carbon source and algal-bacterial uptake. Accelerated nitrogen removal with simultaneously improved cathode performance was observed at high concentration of nitrogen and phosphate buffer due to enhanced algal activities for photosynthetic oxygen release and enhanced algal-bacterial interactions for nitrogen transformation. Addition of external organic carbon negatively affected nitrification and decreased cathode potential due to oxygen consumption by aerobic carbon oxidation but enhanced denitrification due to continuous release of high concentration of photosynthetically produced dissolved organic matters by alga. The PBEC was demonstrated as an energy-saving approach for high-strengthen nitrogenous wastewater treatment.

Eriocitrin from lemon suppresses the proliferation of human hepatocellular carcinoma cells through inducing apoptosis and arresting cell cycle.

Hepatocellular carcinoma is a lethal cancer with high recurrence ratio and lacks effective therapeutics. In the past few years, it has been reported that increased intake of vegetables and fruits could reduce the cancer incidence, which suggests dietary agents might possess anticancer effects. Eriocitrin is a flavonoid isolated from lemon, which is known as a strong antioxidant agent. We here for the first time demonstrated that eriocitrin could inhibit the proliferation of hepatocellular carcinoma cell lines by arresting cell cycle in S phase through up-regulation of p53, cyclin A, cyclin D3 and CDK6. Furthermore, we found that eriocitrin could trigger apoptosis by activating mitochondria-involved intrinsic signaling pathway. Thus, eriocitrin might be regarded as a potential chemopreventive natural product to inhibit the early malignant transformation of hepatocellular carcinoma.