The effect of fermentor temperatures and moisture content of substrate on the nutritive value of fermented palm oil sludge

English. A series of experiment was designed in order to improve the nutritive value of palm oil sludge (POS) through fermentation. POS was fermented in a fermentor chamber with different temperatures (28 and 32 deg. C) and initial moisture content of the substrate (50, 55 and 60 percent). The nutrient content (crude protein, true protein, in vitro-dry matter and protein digestibility and crude fibre) of the fermented products were evaluated at different stages of the fermentation, i.e.: before incubated (F0), 3 d after aerobic incubation (F3) and 2 d anaerobic incubation after F3 (EN). Cellulase and mannanase activity of the EN products were also measured before and after dried at 60 deg. C. Fermentation at 32 deg. C produced better product (higher nutritive values), although the in vitro dry matter digestibility was not affected by the temperatures. All parameters measured were not significantly influenced by the initial moisture content of the substrate value of unincubated POS (F0) was significantly poorer than the F3 and EN and there was not different in nutrient value between F3 and EN. Soluble nitrogen and in vitro dry matter digestibility were not significantly affected by the stages of the fermentation. Mannanase activity in the EN product was significantly higher when the fermentation was performed at 32 deg. C than those at 28 deg. C and the enzyme activity was reduced after dried (320.7 vs 201.8 U/g DM). The cellulase activity of the fresh/wet fermented product at 28 deg. C was significantly higher than those produced at 32 deg. C, but the reverse was occurred in the dry products. It is concluded that fermentation process of palm oil sludge at 32 deg. C and initial moisture content of 50-60 percent produced better (in vitro) nutritive value

Indonesian. Serangkaian penelitian dirancang untuk meningkatkan nilai gizi lumpur sawit melalui proses fermentasi. Lumpur sawit difermentasi pada suhu ruangan (28 dan 32 der. C) dan kadar air substrat yang berbeda (50, 55 dan 60 persen). Produk yang dihasilkan kemudian dianalisis nilai gizinya (kadar protein kasar, protein sejati, daya cerna in vitro bahan kering dan protein dan kadar serat kasar) pada berbagai tahapan proses fermentasi: saat sebelum inkubasi (F0), 3 hari setelah inkubasi aerobik (F3) dan 2 hari proses enzimatis anaerobik setelah F3 (EN). Aktivitas enzim selulase dan mananase produk fermentasi EN juga diukur sebelum dan setelah dikeringkan pada suhu 60 der. C. Proses fermentasi pada suhu 32 der. C menghasilkan kadar gizi yang lebih baik. Akan tetapi, daya cerna bahan kering in vitro tidak nyata dipengaruhi oleh suhu ruangan. Kadar air substrat ternyata tidak berpengaruh terhadap semua parameter yang diukur. Nilai gizi lumpur sawit yang belum diinkubasi (F0) nyata lebih rendah daripada F3 dan EN, sedangkan antara F3 dan EN tidak berbeda nyata. Kadar nitrogen terlarut dan daya cerna bahan kering in vitro tidak nyata dipengaruhi oleh tahapan proses fermentasi. Aktivitas enzim mananase produk fermentasi yang dihasilkan pada suhu ruangan 32 der. C nyata lebih tinggi daripada suhu ruangan 28 der. C dan aktivitas enzim mananase menurun setelah dikeringkan (320,7 vs 201,8 U/g BK). Aktivitas enzim selulase produk segar/basah yang dihasilkan pada suhu 29 der. C lebih tinggi daripada yang dihasilkan pada suhu ruangan 32 der. C, tetapi keadaan sebaliknya terjadi pada produk fermentasi setelah dikeringkan. Dari suhu penelitian ini disimpulkan bahwa proses fermentasi lumpur sawit akan menghasilkan produk dengan nilai gizi (in vitro) yang lebih baik bila dilakukan pada suhu 32 der. C, dengan kadar air substrat antara 50-60 persen