Methane fermentation of rubber (Hevea brasiliensis) latex effluent.

Four species of bacteria capable of CH4 fermentation of rubber latex effluent were isolated and identified as a Methanococcus, a strain of M. vannielii, a Methanobacterium and a strain of M. omelianskii. Auxanographic tests using the four strains showed growth and CH4 formation on a basal medium containing mineral salts or added H2 and Co2. Varied response was obtained when the basal medium was added to formate, acetate, butyrate, methanol, ethanol, and glucose. Previous work has established acid fermentation of Hevea latex arising from bacterial contamination and decomposition of the non-rubber constituents which consist of N-compounds, 2% quebrachitol, and smaller concentration of carbohydrates. This suggests that reduction of CO2 and fermentation of acids formed during metabolism of Hevea latex are possible pathways of CH4 production.     

Products of non-reductive CO2 assimilation in the halophilic archaebacterium Haloferax mediterranei.

The products of CO2 fixation by heterotrophically grown Haloferax mediterranei were analysed. The main 14C-labelled alpha-ketoacid detected following incubation with NaH14CO3 and pyruvate or propionate was pyruvate. In presence of these organic acids and NH4+, 14CO2 was incorporated into glutamic and aspartic acids and alanine.