Spring In Malaysia Research Articles

A new thermostable lipase byAneurinibacillus thermoaerophilus strain HZ: nutritional studies

A thermophilicAneurinibacillus thermoaerophilus strain HZ producing a thermostable lipase was isolated from hot spring in Malaysia. Maximum lipase production byA. thermoaerophilus strain HZ was obtained at pH 7.5 when grown under shaking condition (150 rpm) at 60 °C for 48 h. In order to increase the lipase production, optimization of nutritional factors was studied. Maximum lipase production was obtained in the presence of peptone as the best nitrogen source. Among the various natural and synthetic triglycerides used, olive oil served as the best substrate for production of extracellular lipase. Additional carbon sources added in this study did not significantly increase the lipase production while metal ions, Mg2+, Na+, Ca2+ and K+ were found to enhance lipase production. In addition, lipase production was stimulated by Tween 85 as a surfactant.

Screening and identification of extracellular lipase-producing thermophilic bacteria from a Malaysian hot spring

Seven lipase-producing thermophilic bacteria (ST 1, ST 4, ST 6, ST 7, ST 8, ST 9 and ST 10) were isolated from the Setapak hot spring in Malaysia. The crude extracellular lipases recovered by ultrafiltration of cell-free culture supernatant were reacted in an olive oil mixture and their lipolytic activities were compared. Identification of the bacteria was carried out using the Biolog system and biochemical tests. Strain ST 7 that exhibited the highest lipolytic activity of 4.58 U/ml was identified as belonging to the Bacillus genus. Strain ST 6 with an activity of 3.51 U/ml, was identified as Ralstonia paucula. The lipolytic activities of strains ST 1, ST 4, ST 8, ST 9 and ST 10 were 2.39, 1.84, 2.38, 1.80 and 2.62 U/ml respectively. Strains ST 1, ST 4, and ST 10 were identified as Ralstonia paucula while strains ST 8 and ST 9 were Bacillus spp. Strains ST 7 and ST 9 were tentatively identified as Bacillus thermoglucosidasius, Bacillus stearothermophilus or Bacillus coagulans, whereas strain ST 8 was tentatively identified as Bacillus subtilis.