Investigating Cellular Responses During Photohydrogen Production by the Marine Microalga Tetraselmis subcordiformis by Quantitative Proteome Analysis

High-throughput proteomics and metabolomic studies guide re-engineering of metabolic pathways in eukaryotic microalgae: A review

Eukaryotic microalgae are a rich source of commercially important metabolites including lipids, pigments, sugars, amino acids and enzymes. However, their inherent genetic potential is usually not enough to support high level production of metabolites of interest. In order to move on from the traditional approach of improving product yields by modification of the cultivation conditions, understanding the metabolic pathways leading to the synthesis of the bioproducts of interest is crucial. Identification of new targets for strain engineering has been greatly facilitated by the rapid development of high-throughput sequencing and spectroscopic techniques discussed in this review. Despite the availability of high throughput analytical tools, examples of gathering and application of proteomic and metabolomic data for metabolic engineering of microalgae are few and mainly limited to lipid production. The present review highlights the application of contemporary proteomic and metabolomic techniques in eukaryotic microalgae for redesigning pathways for enhanced production of algal metabolites.

Omics-prediction of bioactive peptides from the edible cyanobacterium Arthrospira platensis proteome

BACKGROUND

Bioinformatics approaches are widely used to evaluate the prospects of novel protein sources in bioactive peptide research. Edible cyanobacteria are considered as potential protein precursors. However, the abundance of unicellular cyanobacterial proteins is largely unknown and highly dynamic according to the cultivation conditions, which need to be considered in this research field. The objective of this work was to evaluate the protein abundance of Arthrospira platensis, as well as to map the bioactive peptide sequences from the high-abundance proteins of the A. platensis proteome.

RESULTS

The high-abundance proteins of the A. platensis proteome were identified with a high-performance liquid chromatography-tandem mass spectrometry-based method. A total of 593 proteins were detected and quantified. The occurrence frequency of the bioactive peptides in A. platensis proteome was calculated according to the amino acid sequences via the bioinformatics approaches. Further in silico digested by trypsin, pepsin and chymotrypsin, these proteins liberated 78, 99, and 96 bioactive peptides, respectively. In each case, angiotensin-converting enzyme inhibitors and dipeptidyl peptidase IV inhibitors were enriched.

CONCLUSION

This work will help rationally design the protocols for cyanobacterial cultivation, protein pre-treatment and peptide separation, and further produce more peptides with specific functions. © 2017 Society of Chemical Industry.

Effect of Light/Dark Regimens on Hydrogen Production by Tetraselmis subcordiformis Coupled with an Alkaline Fuel Cell System

To improve the photoproduction of hydrogen (H₂) by a green algae-based system, the effect of light/dark regimens on H₂ photoproduction regulated by carbonyl cyanide m-chlorophenylhydrazone (CCCP) was investigated. A fuel cell was integrated into a photobioreactor to allow online monitoring of the H₂ evolution rate and decrease potential H₂ feedback inhibition by consuming the generated H₂ in situ. During the first 15 h of H₂ evolution, the system was subjected to dark treatment after initial light illumination (L/D = 6/9 h, 9/6 h, and 12/3 h). After the dark period, all systems were again exposed to light illumination until H₂ evolution stopped. Two peaks were observed in the H₂ evolution rate under all three light/dark regimens. Additionally, a high H₂ yield of 126 ± 10 mL L^-1 was achieved using a light/dark regimen of L 9 h/D 6 h/L until H₂ production ceased, which was 1.6 times higher than that obtained under continuous illumination. H₂ production was accompanied by some physiological and morphological changes in the cells. The results indicated that light/dark regimens improved the duration and yield of H₂ photoproduction by the CCCP-regulated process of Tetraselmis subcordiformis.