Bacterial assemblages structure in intensive cultivations of the microalga Tetradesmus obliquus

The present study shows the characterization of the bacterial communities associated with different systems during the cultivation of the microalga Tetradesmus obliquus. For that, sequential cultivation was performed in three different systems: (1) Photobioreactor bench-scale; (2) flat-panel photobioreactor; and (3) thin-layer cascade. Cultures were monitored daily for growth parameters and biomass samples were collected for characterization of bacterial communities using metagenomic. A total of 195,177 reads were produced, resulting in the identification of 72 OTUs. In the grouping of bacterial communities, 3 phyla, 6 classes, 28 families, and 35 taxa were found. The bacteria Brevundimonas and Porphyrobacter had a higher relative abundance compared with other taxa found. These taxa were present in all cultivation systems forming a possible core community. Bacterial communities associated with different cultivation systems of the microalga T. obliquus showed an increase in taxa richness and diversity in the super-intensive and intensive systems.

An overview on microalgae as renewable resources for meeting sustainable development goals

The increased demands and dependence on depleted oil reserves, accompanied by global warming and climate change have driven the world to explore and develop new strategies for global sustainable development. Among sustainable biomass sources, microalgae represent a promising alternative to fossil fuel and can contribute to the achievement of important Sustainable Development Goals (SDGs). This article has reviewed the various applications of microalgal biomass that includes (i) the use in aquaculture and its sustainability; (ii) commercial value and emerging extraction strategies of carotenoids; (iii) biofuels from microalgae and their application in internal combustion engines; (iv) the use and reuse of water in microalgae cultivation; and (v) microalgae biotechnology as a key factor to assist SDGs. The future prospects and challenges on the microalgae circular bio economy, issues with regard to the scale-up and water demand in microalgae cultivation are also highlighted.

Noise-induced hearing loss and stress-prone behavior

Previous research found a relationship between stress-prone personality (pattern A) and noise-induced vasoconstriction in normal-hearing adult subjects. The present research sought evidence for a possible relationship between susceptibility to high-frequency noise-induced permanent threshold shift (NIPTS) found among industrial workers and the vasoconstrictive behavior of the same workers when they were exposed to high-intensity noise. It was hypothesized that pattern A workers would show more vasoconstriction in the presence of high-intensity noise, and hence more susceptibility to NIPTS, than pattern B (non-stress-prone) workers. The 35 male subjects tested were divided into two groups. Group 1 contained 16 subjects who showed significant vasoconstriction in noise; group I subjects were clearly pattern A types. Group II contained 19 subjects who did not show significant vasoconstriction in noise; Group II contained mostly pattern B but a few pattern A subjects. Unexpectedly, it was the group II subjects who showed the most susceptibility to NIPTS; the difference between the means of the two groups was statistically significant (p greater than or equal to 0.001). The explanation for this unexpected finding is obscure.