Development and fabrication of disease resistance protein in recombinant Escherichia coli

High-level production and extraction of C-phycocyanin from cyanobacteria Synechococcus sp. PCC7002 for antioxidation, antibacterial and lead adsorption

Global warming and climate change because carbon dioxide (CO₂) release to atmosphere is the forecasting challenges to human being. We are facing how to overcome the dilemma on the balance between economic and environment, thus taking more efforts on green processes to meet agreement of sustainable society are urgent and crucial. The absorption of CO₂ by microalgae reduces the impact of CO₂ on the environment. In this study, the CO₂ removal efficiency was the highest in the culture of Cyanobacterium Synechococcus sp. PCC7002 (also called blue-green algae), at 2% CO₂ to reach a value of 0.86 g-CO₂/g-DCW. The main product of PCC7002 is C-phycocyanin (C-PC) which regarding to phycobilisome complex in all cyanobacterial species. A 160% increasing C-PC was achieved in the cultivation under 100 μmol/m²/s light intensity, 12:12 light-period with 2% CO₂ at 30 °C. The mix-culture of nitric and ammonia ions had positive effect on the cell growth and C-PC accumulation, thus realized the highest yield of 0.439 g-CPC/g-DCW. Additionally, the partial purified C-PC displayed 89% antioxidant activity of 2,2-diphenyl-1-picryhydrazyl (DPPH) and 11% of superoxide free radical scavenging activity, respectively. The production of C-PC from PCC7002 reduced the CO₂ emission and exhibited antibacterial activity against Escherichia coli and lead ion adsorption at room temperature, which has the great potential for eco-friendly application.

Production, isolation and characterization of C-phycocyanin from a new halo-tolerant Cyanobacterium aponinum using seawater

A halo-tolerant Cyanobacterium aponinum PCC 10605 was applied for the first time to produce high-level C-phycocyanin (C-PC). Combined with chemical extraction with sodium phosphate buffer and physical treatment using high pressure homogenization, a higher titer of C-PC was achieved. The culture conditions were optimized by mixing nitrate and ammonia ions, 2% carbon dioxide, and conditional light intensity. Thus, strain PCC10605 produced the highest titer C-PC of 0.652 g/g-DCW in the N1A2 medium with 10% light intensity and 16:8 light-period on day 7. PCC10605 accumulated 0.51 g-CPC/g-DCW at 20 g/L NaCl, while it grew normally in seawater with 30 g/L salinity, thus confirmed that PCC10605 was halo-tolerant strain. Besides, PCC10605 survived in 0.12 g/L phosphate medium that has never been reported. Finally, the purified C-PC exhibited DPPH, superoxide scavenging activity and antibacterial activity, which displayed 87.6%, and 18.7% removal of free radical, and 1.98 cm of inhibition zone for Escherichia coli.

Challenges and opportunities of bioprocessing 5-aminolevulinic acid using genetic and metabolic engineering: a critical review

5-Aminolevulinic acid (5-ALA), a non-proteinogenic five-carbon amino acid, has received intensive attentions in medicine due to its approval by the US Food and Drug Administration (FDA) for cancer diagnosis and treatment as photodynamic therapy. As chemical synthesis of 5-ALA performed low yield, complicated processes, and high cost, biosynthesis of 5-ALA via C4 (also called Shemin pathway) and C5 pathway related to heme biosynthesis in microorganism equipped more advantages. In C4 pathway, 5-ALA is derived from condensation of succinyl-CoA and glycine by 5-aminolevulic acid synthase (ALAS) with pyridoxal phosphate (PLP) as co-factor in one-step biotransformation. The C5 pathway involves three enzymes comprising glutamyl-tRNA synthetase (GltX), glutamyl-tRNA reductase (HemA), and glutamate-1-semialdehyde aminotransferase (HemL) from α-ketoglutarate in TCA cycle to 5-ALA and heme. In this review, we describe the recent results of 5-ALA production from different genes and microorganisms via genetic and metabolic engineering approaches. The regulation of different chassis is fine-tuned by applying synthetic biology and boosts 5-ALA production eventually. The purification process, challenges, and opportunities of 5-ALA for industrial applications are also summarized.