<![CDATA[Abstract: Kepok banana peel is one of the organic wastes that can pollute the environment if not managed properly, yet it has the potential to be used as a raw material for biocatalysts. This study aimed to produce a biocatalyst from kepok banana peel waste and to analyze the effect of adding the biocatalyst and Bacillus subtilis bacteria in reducing the Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) of tofu wastewater. The biocatalyst was produced through 12 weeks of anaerobic fermentation using a molasses, banana peel, and water ratio of 1:3:10. Two treatments were applied, namely the addition of biocatalyst (P1) and the addition of biocatalyst and bacteria (P2), at doses of 10%, 15%, and 20% with three replications and a 48-hour contact time. Data were analyzed using the Shapiro-Wilk normality test, two-way ANOVA, and Tukey post hoc test. The results showed that the biocatalyst was not able to reduce the BOD and COD of tofu wastewater; both parameters actually increased as the dose increased. The dose factor had a significant effect on the increase in BOD and COD (Sig = 0.000), whereas the treatment factor and its interaction were not significant. Thus, the addition of the biocatalyst was not able to reduce the pollutant load and instead increased the organic load of the tofu wastewater. This finding indicates the need for biocatalyst purification prior to application in order to minimize free organic compounds, along with adjustment of dose and contact time so that the degradation process takes place optimally. Keywords: Biocatalyst, Kepok Banana Peel Waste, Tofu Wastewater, BOD, COD Abstrak: Limbah kulit pisang kepok merupakan limbah organik yang dapat mencemari lingkungan apabila tidak dikelola dengan baik, namun berpotensi dimanfaatkan sebagai bahan baku biokatalisator. Penelitian ini bertujuan membuat biokatalisator dari limbah kulit pisang kepok serta menganalisis pengaruh penambahan biokatalisator dan bakteri Bacillus subtilis dalam mereduksi kadar Biochemical Oxygen Demand (BOD) dan Chemical Oxygen Demand (COD) limbah cair tahu. Biokatalisator dibuat melalui fermentasi anaerob selama 12 minggu dengan perbandingan molase, kulit pisang kepok, dan air 1:3:10. Penelitian menggunakan dua perlakuan, yaitu penambahan biokatalisator (P1) serta penambahan biokatalisator dan bakteri (P2), dengan dosis 10%, 15%, dan 20% dan tiga kali ulangan pada waktu kontak 48 jam. Data dianalisis dengan uji normalitas Shapiro-Wilk, ANOVA dua arah, dan uji lanjut Tukey. Hasil penelitian menunjukkan biokatalisator yang dihasilkan belum mampu menurunkan kadar BOD dan COD limbah cair tahu; nilai kedua parameter justru meningkat seiring bertambahnya dosis. Faktor dosis berpengaruh signifikan terhadap peningkatan nilai BOD dan COD (Sig = 0,000), sedangkan faktor perlakuan dan interaksinya tidak signifikan. Dengan demikian, penambahan biokatalisator belum mampu mereduksi kadar pencemar dan justru meningkatkan beban organik limbah cair tahu. Temuan ini mengindikasikan perlunya pemurnian biokatalisator sebelum diaplikasikan untuk meminimalkan senyawa organik bebas, disertai penyesuaian dosis dan waktu kontak agar proses degradasi berlangsung optimal. Kata Kunci: Biokatalisator, Kulit Pisang Kepok, Limbah Cair Tahu, BOD, COD]]>
