The recent paper in explicitly discusses the matter "The prepared tokoroten was frozen at −20C, then thawed at room temperature. The thawed tokoroten separated into agar and liquid parts naturally,... " https://www.tandfonline.com/doi/abs/10.1080/00318884.2026.26...

I've had cells growing fine in 20 L Cytiva wave bags and then fail to grow in 20 L Sartorius wave bags. Anyone that tells you they know how a cell grows is lying to themselves :)

Maybe there is something else in Gelidium amansii that it needs, if the tokoroten was produced in the traditional way?