Heterologous expression and characterization of glycoside hydrolase with its potential applications in hyperthermic environment.

With the progressive focus on renewable energy via biofuels production from lignocellulosic biomass, cellulases are the key enzymes that play a fundamental role in this regard. This study aims to unravel the characteristics of Thermotoga maritima MSB8 (Tma) (a hyperthermophile from hot springs) thermostable glycoside hydrolase enzyme. Here, a glycoside hydrolase gene of Thermotoga maritima (Tma) was heterologously expressed and characterized. The gene was placed in the pQE-30 expression vector under the T5 promotor, and the construct pQE-30-Gh was then successfully integrated into Escherichia coli BL21 (DH5α) genome by transformation. Sequence of the glycoside hydrolase contained an open reading frame of 2.124 kbp, encoded a polypeptide of 721 amino acid residues. The molecular weight of the recombinant protein estimated was 79 kDa. The glycoside hydrolase was purified by Ni+2-NTA affinity chromatography and its enzymatic activity was investigated. The recombinant enzyme is highly stable within an extreme pH range (2.0-7.0) and highly thermostable at 80 °C for 72 h indicating its viability in hyperthermic environment and acidic nature. Moreover, the Ca2+ and Mn2+ introduction stimulated the residual activity of recombinant enzyme. Conclusively, the thermostable glycoside hydrolase possesses potential to be exploited for industrial applications at hyperthermic environment.

Effective removal of the herbicide glyphosate by the kelp Saccharina japonica female gametophytes from saline waters and its mechanism elucidation.

Glyphosate has been widely and extensively used for weed control because of its excellent herbicidal profile and low costs. However, more than 750 glyphosate products are on the market and are increasingly regarded as water pollutants as they cause adverse effects on aquatic life. Dry cell weight and photosynthesis of Saccharina japonica female gametophytes increased when glyphosate was used as the sole phosphorus source at the concentration of less than 20 mg L-1. Nuclear magnetic resonance (NMR) analysis unambiguously confirmed that female gametophytes of the brown alga Saccharina japonica have the capability of breaking the C-P bond of glyphosate to orthophosphate, which finds the enormous potential of the most common seaweed to degrade the most widely used herbicide in the world. Furthermore, this is the first report on the use of glyphosate as the sole phosphorus source for the growth of eukaryotic cells. Because of the wide distribution and relatively easy cultivation of the fast-growing brown alga Saccharina japonica on the coast, our results set a promising stage for developing large macroalgae-based biotechnologies that can be applied for the remediation of contaminated seawater, which is greener and more cost-effective than conventional treatment methods.