Selection and characterization of mutants of Phanerochaete chrysosporium exhibiting ligninolytic activity under nutrient-rich conditions

Journal Article · Wed Aug 01 04:00:00 EDT 1990 · Applied and Environmental Microbiology; (USA)

OSTI ID:5985606

Tien, Ming; Myer, S B ^[1]

---

1. Pennsylvania State Univ., University Park (USA)

Synthesis of the ligninolytic system of the wood-degrading fungus Phanerochaete chrysosporium is induced during secondary metabolism, brought about by nitrogen, carbon, or sulfur starvation. We describe here a strategy for selection of mutants which are ligninolytic (lignin{yields}CO{sub 2}) and overproduce lignin-degrading enzymes (ligninases) under nutrient-rich conditions (during primary metabolism). The strategy is based on using an adduct of lysine and a lignin model compound. Ligninase-dependent oxidation of this adduct releases free lysine, which complements the lysine requirements of a lysine auxotroph. Accordingly, a lysine auxotroph was mutagenized by UV irradiation and survivors were plated onto medium containing the adduct and high ammonia nitrogen. Four mutants which overproduce the ligninase isozymes were isolated by this procedure. Further characterization of one of the mutants, PSBL-1, indicated that the predominant isozymes produced are H1 (pI = 4.7) and H2 (pI = 4.4). The ligninase activity of PSBL-1, measured by veratryl alcohol oxidation, peaks on day 5 at over 1,000 U{center dot}liter{sup {minus}1}. The mutant PSBL-1 was also able to degrade ({sup 14}C)lignin to {sup 14}CO{sub 2}, indicating that the complete ligninolytic system is deregulated.

• OSTI ID: 5985606
• Journal Information: Applied and Environmental Microbiology; (USA), Journal Name: Applied and Environmental Microbiology; (USA) Vol. 56:8; ISSN 0099-2240; ISSN AEMID
• Country of Publication: United States
• Language: English

Related Subjects

09 BIOMASS FUELS
090900* -- Biomass Fuels-- Processing-- (1990-)
54 ENVIRONMENTAL SCIENCES
540211 -- Environment
Terrestrial-- Basic Studies-- Radiometric Techniques-- (1990-)
550501 -- Metabolism-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
BIODEGRADATION
BIOLOGICAL PATHWAYS
CARBOHYDRATES
CARBON 14 COMPOUNDS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CARBOXYLIC ACIDS
CHALCOGENIDES
CHEMICAL REACTIONS
DECOMPOSITION
ELECTROMAGNETIC RADIATION
ENZYME ACTIVITY
ENZYMES
EUMYCOTA
FUNGI
ISOENZYMES
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LIGNIN
LYSINE
MUTAGENESIS
MUTANTS
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXIDES
OXIDOREDUCTASES
OXYGEN COMPOUNDS
PEROXIDASES
PHANEROCHAETE
PLANTS
POLYSACCHARIDES
RADIATIONS
SACCHARIDES
TRACER TECHNIQUES
ULTRAVIOLET RADIATION