No abstract

Mikroalga berpotensi sebagai agen fikoremediasi air sisa dan metabolit yang terhasil dalam biojisim mikroalga mampu diaplikasikan dalam bidang bioteknologi. Pertumbuhan mikroalga dalam air sisa menjadi petunjuk bahawa mikroalga mampu hidup dalam persekitaran ekstrim dan menjadi agen fikoremediasi air sisa. Oleh itu, model matematik yang terbaik bagi kinetik pertumbuhan mikroalga yang dikultur dalam air sisa perlu dikaji bagi menentukan model yang tepat untuk digunakan pada masa akan datang. Dalam kajian ini, penilaian model matematik yang terbaik terhadap tiga mikroalga tempatan, Characium sp. UKM1, Chlorella sp. UKM2 dan Coelastrella sp. UKM4 yang dikultur dalam air larut resapan sintetik dianalisis dengan menggunakan tiga model matematik iaitu logistik, logistik terubah suai dan Gompertz terubah suai. Selain itu, analisis statistik dijalankan bagi penentuan model terbaik dengan mengambil kira nilai regressi terubah suai (adj R2), ralat tambah kuasa dua (SSE), punca min ralat kuasa dua (RMSE), faktor bias (BF), faktor kejituan (AF) dan peratus ramalan ralat piawai (%SEP). Hasil menunjukkan model yang terbaik bagi ketiga-tiga mikroalga dalam air larut resapan sintetik adalah model Gompertz terubah suai. Ini disebabkan oleh beberapa ciri antaranya plot residual yang mendekati model matematik, nilai BF yang mendekati nilai satu, serta nilai terendah %SEP berbanding model matematik yang lain. Kesimpulannya, model Gompertz terubah suai adalah model penyesuaian yang terbaik terhadap pertumbuhan mikroalga dalam air larut resapan sintetik.

Microalgae are extensively used in industry due to their potential in producing high-value metabolites. The good microalgae growth kinetics performance is essential owing to excellent microalgae biomass harvesting efficiency. Therefore, the best mathematical model for the growth kinetics of microalgae is required to predict the correct growth kinetics value and helps in the elucidation of downstream processes. This study embarks on the objective to determine the best mathematical models for three local microalgae which are Characium sp. UKM1, Chlorella sp. UKM2 and Coelastrella sp. UKM4 cultured in Bold Basal Media (BBM). The four mathematical models are used to evaluate the growth kinetics of microalgae which include logistic model (Lm), modified logistic model (MLm), modified Gompertz model (MGm) and Baranyi-Roberts model (BRm). The experimental data were compared to the predicted data through the residual plot. The comparison shows that BRm is the best model to fit UKM1, UKM2 and UKM4 due to the experimental data which is close to the x-axis of the residual plot indicating the data were fitted the best to the BRm. The statistical analysis confirmed that all microalgae growth patterns exhibited that the BRm is the best model owing to the lowest percentage of standard error prediction indicating the lowest error compared to the other models. In addition, accuracy and bias factors are near to one which assess the precision of these models. In conclusion, the growth of UKM1, UKM2 and UKM4 grown in BBM is best fitted to the Baranyi-Roberts model.