Development of aquafeed ingredient by solid state fermentation of the crinklegrass , Rhizoclonium riparium on a laboratory scale 1

Solid state fermentation (SSF) of the crinkle grass Rhizoclonium riparium var. implexum was done to develop it as an aquafeed ingredient. A bacterial strain, Micrococcus flavus (L11) or a fungal strain Kluyveromyces sp. (F2) or their combination (LF) were inoculated on the seaweed base material for 14 days. During the fermentation period, changes in pH, lactic acid, ethanol and total protein content were determined. Results showed that the bioconversion of crinklegrass into a fermented Rhizoclonium meal (FRM) was best processed by an enzyme pre-treatment using 375 U cellulase and α-amylase followed by inoculation with Kluyveromyces sp. (F2) and supplementation of 10% substrate under SSF conditions. At the end of the 14-day incubation, protein content significantly (p < 0.05) increased from 15% to 22%, accounting for 41% protein improvement. Results of the present study show that SSF of crinkle grass Rhizoclonium implexum can increase its protein content thus making it a potential protein supplement for aquafeeds.