In biotechnology, valuable products are produced by liquid cultures, where individual cells grow freely in a nutrient-rich medium. These cultures are called ‘cell suspensions’. In bioreactors, the suspensions are constantly shaken, creating certain hydrodynamics within the culture medium. This hydrodynamics affects the output quantity of the desired products, such as phytochemicals, proteins, enzymes and antibodies.

A problem before technologists is how to optimise the design of a bioreactor to maximise the production of useful products.

To address this, a team of scientists at IIT-Madras (Vidya Muthulakshmi Manickavasagam, Prof Nirav Bhatt and Prof Smita Srivastava) used computational fluid dynamics (CFD) to rationally design and select key features of a bioreactor, especially the impeller type, and the operating conditions, so that the hydrodynamic environment in the bioreactor would match the favourable conditions in shake flasks. By doing so, they addressed the drop in biomass productivity that usually occurs during scale-up from lab to industry.

Traditionally, bioreactor designs are selected through trial and error to match shake-flask productivity. This approach is inefficient for plant cells, which grow slowly and require long cultivation times. But the use of CFD enhanced efficiency.

Studying the medicinal plant Viola odorata, researchers modelled fluid flow in both shake flasks and bioreactors; they showed that maintaining “a constant shear environment” (forces created by one layer sliding over another) is crucial for preserving cell growth.

Overall, the study demonstrated that CFD offers a rational, time-saving way to design and scale up bioreactors for plant cell cultures, replacing inefficient trial-and-error methods.

Detox freshwater sponge

Freshwater sponges found in the Sundarban delta could play a significant role in monitoring and reducing toxic metal pollution, according to a new study by scientists at the Bose Institute, Kolkata. The research shows that these sponges can accumulate hazardous metals such as arsenic, lead and cadmium while hosting specialised microbial communities that help detoxify polluted water.

The study, published in Microbiology Spectrum of the American Society for Microbiology, examined freshwater sponges from the Sundarbans, a region facing increasing environmental stress from industrial and agricultural pollution. Freshwater sponges are among the earliest multicellular organisms and act as natural filters, processing large volumes of water and contributing to ecosystem health.

Led by Dr Abhrajyoti Ghosh of the Bose Institute’s Department of Biological Sciences, the research found that the microbial communities living within the sponges are distinct from those in the surrounding water. These microbes are shaped by sponge species and habitat, and enriched with genes linked to metal transport, metal resistance and antimicrobial resistance, indicating their role in surviving and detoxifying contaminated environments.

The study also represents the first detailed report on bacterial diversity in the freshwater sponges found in the Sundarbans. It was supported by a DST SERB national post-doctoral fellowship awarded to Dr Dhruba Bhattacharya.

Given the widespread heavy metal contamination across the Gangetic plain, the researchers say freshwater sponges could serve as effective bioindicators of water quality and natural tools for bioremediation. The findings open new possibilities for sustainable approaches to managing pollution in estuarine and freshwater ecosystems.

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Published on January 12, 2026