Induction, purification, and characterization of a thermo and pH stable laccase from Abortiporus biennis J2 and its application on the clarification of litchi juice

Figures & data

Fig. 1. The time course of laccase secretion by Abortiporus biennis J2 in basal laccase production medium at 30 °C on a rotary shaker at 150 rpm.

Fig. 2. Effect of different inducers on laccase production of Abortiporus biennis. Cu²⁺ 0.1 mM, ethanol 0.5 M, tannic acid, vanillin, guaiacol, ferulic acid, and catechol 0.1 mM, respectively.

Table 1. Purification of Laccase from Abortiporus biennis J2.

Purification steps	Protein (mg)	Enzyme activity (U)	Special activity (U/mg)	Purification (fold)	Yield (%)
Crude enzyme	292.3	25360	86.8	1	100
Ammonium sulfate precipitation	139.1	19485	140.1	1.6	76.8
DEAE-Sepharose-FF	45.8	15536	339.2	3.9	61.2
Sephadex-100	25.4	12738	501.5	5.8	46.3

Fig. 3. SDS-PAGE of purified laccase from Abortiporus biennis J2. 1 Standard molecular weight markers, 2 Purified laccase.

Table 2. Comparison of the N-terminal amino acid sequences of Abortiporus biennis laccase with other fungal laccases.

Microorganism	N-terminal amino acid sequences	Accession number	Identity (%)
Abortiporus biennis	1 AIGPTADLNISNADI 15	This work	100
Coriolopsis trogii	24 AIGPTADLTISNADI 38	AMJ39539.1	93
Polyporus brumalis	24 AIGPVADLTISNADI 38	ABN13592.1	87
Trametes hirsuta	22 AIGPTADLTISNAEV 36	AOX15702.1	80
Rigidoporus microporus	22 AIGPVADLHISNANI 36	AAQ82021.1	80
Coriolopsis gallica	1 AIGPVADLTISNANI 15	AAW65485.1	80
Flammulina velutipes	21 AIGPVADLVIANADV 35	AIW01082.1	73
Ganoderma tsugae	22 AIGPVANLTISDADI 36	ABK59825.1	73
Ganoderma fornicatum	22 AIGPVANLTISDAEI 36	ABK59827.1	67
Trametes gibbosa	22 AIGPVADLTITNAEV 36	ADK13091.1	67

Notes: Data from Blast, the NCBI sequence similarity search tool.

Fig. 4. Effect of temperature on laccase activity (a) and stability of purified laccase (b) Relative activity on laccase activity was defined as the percentage of activity measured with respect to the maximum enzyme activity. Original enzyme activity on stability of laccase was defined as 100%.

Fig. 5. Effect of pH on laccase activity (a) and stability of purified laccase (b) Relative activity on laccase activity was defined as the percentage of activity measured with respect to the maximum enzyme activity. Original activity on stability of laccase was defined as 100%.

Fig. 6. Effects of heavy metal ion on the laccase activity. The enzyme activity assayed in the absence of heavy metal ions was recorded as 100%.

Fig. 7. Effect of various enzyme concentration on the reduction of phenol content in litchi juice after laccase treatment. Standard deviations derive from three independent replicates.

Fig. 8. Effect of various enzyme concentration on the clarity (OD₆₅₀) and color (OD₄₂₀) in litchi juice after laccase treatment. Standard deviations derive from three independent replicates.