Contributions of thermotolerant bacteria to organic matter degradation under a hyperthermophilic pretreatment process during chicken manure composting

Composting technology comprising hyperthermophilic pretreatment (at ≥85 °C for 2 to 4 h, HTPRT) and aerobic composting was adopted to accelerate organic matter transformation and enhance nitrogen retention in chicken manure composting. The differences in physio-chemical parameters, successions, and metabolism functions of the bacterial community between HTPRT (85 °C, 4 h) and conventional composting (CK) were compared. The HTPRT composting system reached maturity 18 days in advance of CK. The HTPRT piles showed a lower maximum N loss (27.1% vs. 39.0%). The bacterial structure in the HTPRT system differed remarkably from that in CK. Ureibacillus (22.7%) and Ammoniibacillus (14.1%) were the most predominant species in the thermophilic phase of HTPRT pile, while the curing phase was dominated by Thermobifida (12.8%) and Saccharomonospora (11.8%). The authors’ results suggest that HTPRT improved the physical properties of the feedstock by reducing the bulk density, which favored microbiological activity, and thus improving composting efficiency.

ISOLATION OF THERMOTOLERANT BACTERIA PRODUCING FIBRINOLYTIC ENZYME

Fibrinolytic enzymes were widely used in the treatment of cardiovascular diseases. However, the efficiency of the commercial enzymes are still lack of perfection because there are many side effects as well as not tolerant to downstream processing such as heat sensitive during spray drying process. Therefore, this study presents newly isolated thermophiles bacteria producing fibrinolytic enzyme. Sample was collected from Hot Spring Selayang at Selayang Selangor. Spread plate agar containing skim milk powder growth at pH 7, 53 for 24 hours was utilized to isolate thermotolerant bacteria producing protease. Further isolation on bacteria producing fibrinolytic enzyme was carried out using fibrin plate. 16S rDNA gene sequence analysis was used to identify the genotype of the isolates. 27 colonies of thermotolerant bacteria were isolated, however, only 19 of them showing proteolytic activity. All of the 19 isolates are motile and cocci in shapes, with 4 types of arrangement, which are single, diplo (pair), strepto (chain) and staphylo (cluster). HSP04 and HSP11 are gram positive bacteria and others are gram negative. From 19 isolates only 6 were chosen for further analysis. HSP23 showed the highest fibrinolytic activity compared with others. HSP23 was identified as Bacillus licheniformis with 98 % similarity to Bacillus licheniformis DCM 13 and Bacillus licheniformis strain ATCC 14580.

SKRINING DAN IDENTIFIKASI BAKTERI PENDEGRADASI INULIN DARI SUMBER AIR PANAS PADANG BALIMBIANG DI SOLOK

ABSTRACT Thermophilic bacteria and thermotolerant bacteria are potential sources of thermostable of inulin degradating enzyme, an enzyme which converts inulin into fructose and FOS prebiotics. Isolation and identification of 16S rDNA gene inulin degradation bacteria from hot springs of Padang Balimbiang in Solok have been undertaken. Screening of inulin degradation bacteria was done using direct and undirect methods on medium with inulin or inulin-RBB as a sole carbon source. One inulin degradation bacteria have been obtained from 21 isolates. The isolate was designated as UBCT-030. The isolate is able to grow at temperature 23 °C to 60 °C. According to 16S rDNA gene analysis, phisiology and morphology bacteria on UBCT-030 isolate was identified as Bacillus subtilis. Keywords: inulinase bacteria, hot springs, Bacillus subtilis, inulin, 16S rDNA gene