Local microorganism solution (MOL) is a solution resulting from the fermentation of organic materials containing various microorganisms. MOL acts as a bioactivator for organic materials. This research aimed to evaluate the quality of fruit waste-based MOL solutions (papaya, banana, pineapple) and their potential as bioactivators in animal feed processing. The research used experimental methods with long fermentation treatments, namely: fermentation for 7 days, 14 days, 21 days, and 28 days. The variables observed include: color, aroma, pH, lactic acid, acetic acid, glucose, temperature, and microbial population. The research results showed that fermentation produced the color of the MOL solution from light brown to dark brown, and the aroma was slightly sour. The fermented MOL solution contains an average pH ranging from 4.67 to 6.83, lactic acid 2.33 to 3.23%, acetic acid 1.57 to 2.20%, glucose 5–6, temperature 29–31.3 oC, and total microbes of 1.11 x 106 to 2.13 x 106 cells/ml. Fermentation time can improve the quality of the MOL solution up to day 14, which is characterized by the highest total microbes, namely 2.13 x 106 cells/ml, and can be used as a bioactivator in fermentation. ABSTRAKLarutan mikroorganisme lokal (MOL) adalah larutan hasil fermentasi bahan organik yang mengandung beragam mikroorganisme. MOL berperan sebagai bioaktivator bahan-bahan organik. Tujuan dari penelitian ini adalah untuk mengevaluasi kualitas larutan MOL berbasis limbah buah (pepaya, pisang, nanas) dan potensi sebagai bioaktivator dalam pengolahan pakan ternak. Penelitian menggunakan metode eksperimen dengan perlakuan lama fermentasi yaitu: fermentasi selama 7 hari, 14 hari, 21 hari, dan 28 hari. Variabel yang diamati antara lain: warna, aroma, pH, asam laktat, asam asetat, glukosa, suhu, dan populasi mikroba. Hasil penelitian menunjukkan bahwa fermentasi menghasilkan warna larutan MOL dari coklat muda – coklat tua dan aroma dari sedikit asam - asam. Larutan MOL hasil fermentasi mengandung rataan pH berkisar 4.67 – 6.83, asam laktat 2.33 - 3.23%, asam asetat 1.57 - 2.20%, glukosa 5 – 6, suhu 29 – 31.3 oC, dan total mikroba 1.11 x 106 – 2.13 x 106 sel/ml. Lama fermentasi dapat meningkatkan kualitas larutan MOL sampai hari ke 14 ditandai dengan total mikroba tertinggi yaitu 2.13 x 106 sel/ml dan dapat digunakan sebagai bioactivator dalam fermentasi.