<![CDATA[Fermentation Using Tempe Starter as A Biological Method for Providing Buoyancy to Fish FeedABSTRACTRhizopus sp. is known as the fungus in the making of the soybean tempeh, Rhizopus sp. fermentation brought about chemical as well as physical changes on the substrate including the buoyancy and water stability. These features may be used to biologically prepare floating aquafeed. In this study, tempeh starter was used as the biological agent in the fermentation of commercial sinking fish feed in which fermentation period was varied at 0, 22, 24, 26, 28, 30, 32, and 34 hours. The resulting fermented feeds were oven-dried and their physical qualities were measured and compared to the commercial floating fish feed (positive control). Results showed that the fermented feed gained better water stability, absorption capacity, and floatability compared to those of the commercial sinking feed. These values were however still lower than those of the commercial floating feeds. Thus, fermentation process using tempeh mould has potential to be further improved as a biological method of producing floating fish feed. Keywords: fermentation, floatability, Rhizopus sp., water absorption,  water stability ABSTRAKRhizopus sp. dikenal sebagai jamur yang digunakan dalam pembuatan tempe kedelai. Fermentasi Rhizopus sp. menyebabkan perubahan kimia dan fisika pada substrat, termasuk daya apung dan stabilitas dalam air. Sifat ini bisa dimanfaatkan untuk membuat pakan ikan apung secara biologis. Dalam penelitian ini, ragi tempe digunakan sebagai agen hayati dalam fermentasi pakan ikan tenggelam komersial dimana periode fermentasi divariasi selama 0, 22, 24, 26, 28, 30, 32, dan 34 jam. Pakan fermentasi yang dihasilkan dikeringkan dengan oven, selanjutnya kualitas fisiknya diukur dan dibandingkan dengan pakan ikan apung komersial (kontrol positif). Hasil penelitian menunjukkan bahwa pakan fermentasi memiliki stabilitas dalam air, daya serap air, dan daya apung yang lebih baik dibandingkan dengan pakan tenggelam komersial. Namun nilai ini masih lebih rendah dibandingkan pakan apung komersial. Oleh karenanya, proses fermentasi menggunakan ragi tempe memiliki potensi untuk diperbaiki lebih lanjut sebagai metode biologis pembuatan pakan ikan apung. Received: 11 October 2017               Accepted: 07 November 2017             Published: 04 December 2017Kata Kunci: daya apung, daya serap air, fermentasi, Rhizopus sp., stabilitas dalam air]]>
