Since 2015 the SinoGerman research project SIGN supports water quality improvement in the Taihu region, China

The Taihu (Tai lake) region is one of the most economically prospering areas of China. Due to its location within this district of high anthropogenic activities, Taihu represents a drastic example of water pollution with nutrients (nitrogen, phosphate), organic contaminants and heavy metals. High nutrient levels combined with very shallow water create large eutrophication problems, threatening the drinking water supply of the surrounding cities. Within the international research project SIGN (SinoGerman Water Supply Network, www.water-sign.de), funded by the German Federal Ministry of Education and Research (BMBF), a powerful consortium of fifteen German partners is working on the overall aim of assuring good water quality from the source to the tap by taking the whole water cycle into account: The diverse research topics range from future proof strategies for urban catchment, innovative monitoring and early warning approaches for lake and drinking water, control and use of biological degradation processes, efficient water treatment technologies, adapted water distribution up to promoting sector policy by good governance. The implementation in China is warranted, since the leading Chinese research institutes as well as the most important local stakeholders, e.g. water suppliers, are involved

Unbound phycocyanin as an indicator of cell lysis and dissolved toxin release in cyanobacteria

Rapid cell lysis events during cyanobacterial blooms may result in the release of large amounts of dissolved toxins, which, if occurring near a drinking water plant intake, may pose serious treatment challenges for plant managers. Catastrophic cell lysis can occur naturally, through the activity of cyanophages – as documented in Lake Erie during the Toledo Water Crisis of 2014, or through the overapplication of algicides and water treatment chemicals. Cell lysis is indicated by the release of ‘unbound phycocyanin’ which can be detected fluorometrically by instruments recently developed by bbe-moldaenke. In the present study, unbound phycocyanin in laboratory cultures was continuously monitored following three chemical treatments. Microcystis aeruginosa UTEX 2385 (70 µg/L) was exposed to copper sulfate, PAK-27 (hydrogen peroxide-based algaecide), and potassium permanganate for 96 hours. In a separate experiment Synechococcus sp. cultures were infected with cyanophages and monitored for 144 hours. For PAK-27, copper sulfate, and the phage infection, decline in cell number was preceded by or coincided with the appearance of unbound phycocyanin, suggesting that this real-time fluorescent measurement may be a good indicator of cell wall condition. Results obtained from the other treatments will be further collected and discussed

La Patrie : journal quotidien, politique, commercial et littéraire

10 juillet 18801880/07/10 (A40)

Hunting for pigments in bacterial settlers of the Great Pacific Garbage Patch

Scales BS, Hassenrück C, Moldaenke L, et al. Hunting for pigments in bacterial settlers of the Great Pacific Garbage Patch. Environmental Microbiology. 2024;26(6).The Great Pacific Garbage Patch, a significant collection of plastic introduced by human activities, provides an ideal environment to study bacterial lifestyles on plastic substrates. We proposed that bacteria colonizing the floating plastic debris would develop strategies to deal with the ultraviolet‐exposed substrate, such as the production of antioxidant pigments. We observed a variety of pigmentation in 67 strains that were directly cultivated from plastic pieces sampled from the Garbage Patch. The genomic analysis of four representative strains, each distinct in taxonomy, revealed multiple pathways for carotenoid production. These pathways include those that produce less common carotenoids and a cluster of photosynthetic genes. This cluster appears to originate from a potentially new species of theRhodobacteraceaefamily. This represents the first report of an aerobic anoxygenic photoheterotrophic bacterium from plastic biofilms. Spectral analysis showed that the bacteria actively produce carotenoids, such as beta‐carotene and beta‐cryptoxanthin, and bacteriochlorophyll a. Furthermore, we discovered that the genetic ability to synthesize carotenoids is more common in plastic biofilms than in the surrounding water communities. Our findings suggest that plastic biofilms could be an overlooked source of bacteria‐produced carotenoids, including rare forms. It also suggests that photoreactive molecules might play a crucial role in bacterial biofilm communities in surface water