Use of response surface methodology to optimise the growth of the aquatic moss Taxiphyllum barbieri (Cardot & Copp.) Z.Iwats.

Taxiphyllum barbieri (Cardot & Copp.) Z.Iwats (Java moss) has significant commercial and scientific applications, and optimising its growth is crucial for maximising benefits. The aim of the present study was to investigate key factors influencing the growth of T. barbieri, including nutrient type, nutrient concentration (NC), photoperiod, and levels of dissolved inorganic carbon (DIC). We used response surface methodology (RSM) and Design-Expert software to analyse the complex interactions between these factors and both moss development and chlorophyll and carotenoid production. Maximum growth and pigment production were observed when the NPK (nitrogen, phosphorus, potassium) nutrient medium was used. Optimal conditions for NPK, yielding the maximum relative growth rate (23.8 mg × g−1 d−1), were NC, 82.86%; photoperiod, 6.40 h; and DIC concentration, 0.278 μM. For optimal pigment production in NPK (total chlorophyll and carotenoid content of 2.93 mg × g−1 and 0.199 mg × g−1, respectively), the conditions were NC, 74.29%; photoperiod, 6 h; and DIC concentration, 0.10 μM. These results suggest that higher NC and lower DIC concentration are favourable conditions for pigment production in the NPK medium. The resilience of T. barbieri to increased nutrient levels was also assessed. In the study, the growth parameters for Taxiphyllum barbieri were optimised using the RSM approach. Our findings provide insights into factors influencing moss development, particularly the critical role of NC, photoperiod and DIC in promoting optimal growth and pigment production. This knowledge could inform strategies for enhancing moss cultivation and water pollution mitigation.