PERTANIKA JOURNAL OF TROPICAL AGRICULTURAL SCIENCE

The increased demand for aquaculture has led to significant implications for fish feed supply since its cost contributes to most of the operational cost. The primary protein source in feed ingredients comes from fish meal (FM). However, increasing FM prices and overfishing concerns substantially challenge its sustainable production. Alternatively, single-cell protein (SCP) derived from microbial biomass has demonstrated efficacy as a protein substitute. This study enhanced microbial protein production of Aspergillus terreus UniMAP AA-1 cultivated on palm-pressed fiber (PPF) through the response surface methodology (RSM) approach. Screening of media compositions comprising potassium dihydrogen phosphate (KH₂PO₄), ammonium nitrate (NH₄NO₃), sodium chloride (NaCl), magnesium sulfate heptahydrate (MgSO₄.7H₂O), ferrous sulfate heptahydrate (FeSO₄.7H₂O), copper (II) sulfate pentahydrate (CuSO₄.5H₂O), and zinc sulfate heptahydrate (ZnSO₄.7H₂O) was conducted using the Plackett-Burman design (PBD). The Central Composite Rotatable Design (CCRD) approach was further used to optimize the significant parameters influencing SCP production. Screening by the PBD signifies that NH₄NO₃ and MgSO₄.7H₂O are significant factors enhancing SCP production, with the highest SCP produced of 551 mg/L. Subsequently, optimization by CCRD revealed that the optimum concentration for NH₄NO₃ and MgSO₄.7H₂O were 0.85% and 0.05% (w/v). This optimization strategy has increased the SCP production to 673 mg/L, 22% higher than those obtained earlier. The data gathered in this study may be used for scale-up production of SCP from PPF by A. terreus UniMAP AA-1.