Biological solubilization of untreated north dakota lignite by a mixed bacterial and a mixed bacterial/fungal culture

Biosolubilization of Polish brown coal by Gordonia alkanivorans S7 and Bacillus mycoides NS1020

“…In 1989 Maka et al [7] reported that a consortium of Bacillus strains partially solubilized crude brown coal within 2 weeks and this process was mediated by alkaline substances synthesized by these bacteria. The study of Machnikowska et al [10] revealed that P. putida solubilized crude lignite by 11% and oxidized brown coal by almost 90% within 14 days.…”

“…Their contribution to brown coal biosolubilization was documented for strains of Streptomyces, Bacillus subtilis, Bacillus cereus and Pseudomonas putida [6,7]. Freshly mined brown coal usually contains around 70% water.…”

“…However, lignite biotransformation by Gordonia species has not been reported yet. Bacteria of genus Bacillus have been used in biotechnology for years and are known to attack brown coal [7,11]. One of their attractive features is biosynthesis of biosurfactants, mainly lipopeptides.…”

Biotechnology of Coal

“…The alkaline solubilization of lignite was the first discovered mechanism of microbial coal conversion (QUIGLEY et al, 1987(QUIGLEY et al, ,1988b and later confirmed by several authors (MAKA et al, 1989;RUNNION and COMBIE, 1990a;TOR-ZILLI and ISBISTER, 1994). It is attributed to the high content of carboxylic and phenolic functionalities ( -COOH, -OH) in coal humic acids which can be deprotonated at higher pH (>8), resulting in the formation of watersoluble humates (typically dark-brown to black-colored).…”

Changes of Chemical Properties and Microbiological Succession of Lignites with Weathering.

“…and Aspergillus spp. were isolated as the lignite degraders by some resear-chers8, 11,16,19,24). In general, however, fungi were considered to be the dominant lignite degraders.…”