Enzyme activities of aerobic lignocellulolytic bacteria isolated from wet tropical forest soils.
Lignocellulolytic bacteria have promised to be a fruitful source of new enzymes for next-generation lignocellulosic biofuel production. Puerto Rican tropical forest soils were targeted because the resident microbes decompose biomass quickly and to near-completion. Isolates were initially screened based on growth on cellulose or lignin in minimal media. 75 Isolates were further tested for the following lignocellulolytic enzyme activities: phenol oxidase, peroxidase, β-d-glucosidase, cellobiohydrolase, β-xylopyranosidase, chitinase, CMCase, and xylanase. Cellulose-derived isolates possessed elevated β-d-glucosidase, CMCase, and cellobiohydrolase activity but depressed phenol oxidase and peroxidase activity, while the contrary was true of lignin isolates, suggesting that these bacteria are specialized to subsist on cellulose or lignin. Cellobiohydrolase and phenol oxidase activity rates could classify lignin and cellulose isolates with 61% accuracy, which demonstrates the utility of model degradation assays. Based on 16S rRNA gene sequencing, all isolates belonged to phyla dominant in the Puerto Rican soils, Proteobacteria, Firmicutes, and Actinobacteria, suggesting that many dominant taxa are capable of the rapid lignocellulose degradation characteristic of these soils. The isolated genera Aquitalea, Bacillus, Burkholderia, Cupriavidus, Gordonia, and Paenibacillus represent rarely or never before studied lignolytic or cellulolytic species and were undetected by metagenomic analysis of the soils. The study revealed a relationship between phylogeny and lignocellulose-degrading potential, supported by Kruskal-Wallis statistics which showed that enzyme activities of cultivated phyla and genera were different enough to be considered representatives of distinct populations. This can better inform future experiments and enzyme discovery efforts.
Microbial Communities Group, Deconstruction Division, Joint BioEnergy Institute, United States; Physical Biosciences Division, Lawrence Berkeley National Laboratory, United States; Department of Civil & Environmental Engineering, The University of Tennessee, United States.
Hannah L
HL
Woo
Microbial Communities Group, Deconstruction Division, Joint BioEnergy Institute, United States; Earth Sciences Division, Ecology Department, Lawrence Berkeley National Laboratory, United States; Department of Civil & Environmental Engineering, The University of Tennessee, United States; Department of Microbiology, The University of Tennessee, United States; Department of Earth & Planetary Sciences, The University of Tennessee, United States; Biosciences Division, Oak Ridge National Laboratory, United States.
Terry C
TC
Hazen
Microbial Communities Group, Deconstruction Division, Joint BioEnergy Institute, United States; Biomass Science and Conversion Technology Department, Sandia National Laboratories, United States.
Blake A
BA
Simmons
Microbial Communities Group, Deconstruction Division, Joint BioEnergy Institute, United States; Earth Sciences Division, Ecology Department, Lawrence Berkeley National Laboratory, United States; Microbiology Department, University of Massachusetts Amherst, United States. Electronic address: kristen@post.harvard.edu.
Kristen M
KM
DeAngelis
D000332:Aerobiosis; D001419:Bacteria / Q000145:classification / Q000201:enzymology* / Q000302:isolation & purification / Q000378:metabolism*; D044822:Biodiversity; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D004798:Enzymes / Q000032:analysis*; D008031:Lignin / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D011647:Puerto Rico; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology; D014197:Trees
D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D004798:Enzymes; D012336:RNA, Ribosomal, 16S; C036909:lignocellulose; D008031:Lignin
Biofuels; Biomass degradation; Cellulose; Lignin; Soil lignocellulolytic bacteria; Tropical forest