Ligninolytic enzymes profiling in association with the aggressiveness of Ganoderma boninense isolates

Aims@#This study was designed to examine the enzyme activity of selected virulent isolates of Ganoderma boninense against oil palm. In a separate in vitro assessment, the effect of macronutrients on the mycelial growth of four selected Ganoderma spp. was also tested.@*Methodology and results@#The study involved a comparison of ligninolytic enzymes; lignin peroxidase (LiP), manganese peroxidase (MnP) and laccase (Lac) profiling of eight isolates of G. boninense, categorized into three levels of aggressiveness, with two control isolates (G. boninense PER71 and G. tornatum NPG1) using solid-state fermentation (SSF). The Principal Component Analysis (PCA) revealed that the isolates had a significant production of ligninolytic enzymes on day 80. The most aggressive isolate, ET61 had the highest Lac production. As for the macronutrient test, mycelial growth for all the Ganoderma spp. was highly affected by potassium (K).@*Conclusion, significance and impact of study@#The findings of this study elucidated the characteristics of G. boninense in relation to enzyme production for the degradation of oil palm lignin and the identification of essential nutrients involved in the survival and growth of Ganoderma spp. The study provides vital information on the pathogenic characteristics of G. boninense isolates involved in biomass degradation along with the role of nutrient on the growth of Ganoderma spp. that may influence basal stem rot (BSR) management in the field.

A novel putative non-ligninolytic dehalogenase activity for 3-chloropropionic acid (3CP) utilization by Trichoderma asperellum strain SD1

Aims: Trichoderma asperellum strain SD1 grows on 3-chloropropionic acid (3CP), a β-haloalkanoic acid, and produces a putative extracellular dehalogenase that can degrade this acid. Here we further characterized the fungal enzyme system responsible for biodegradation of 3CP. Methodology and results: The primary qualification of the ligninolytic potential in T. asperellum strain SD1 was performed using guaiacol oxidation. When strain SD1 was grown in liquid minimal medium with the presence of 3CP as the sole carbon source, no lignin peroxidase, manganese peroxidase, or laccase activity was detected. The ligninolytic condition was achieved only in the presence of glucose or when guaiacol was present as an inducer. Under nonligninolytic conditions, 3CP was utilized by strain SD1. Therefore, 3CP was utilized under ligninolytic conditions as well as under non-ligninolytic conditions, suggesting that extracellular peroxidases and laccase are not involved in the degradation of 3CP by T. asperellum strain SD1. Conclusion, significance, and Impact of study: Very few studies have explained the degradation of β-chloro– substituted haloalkanoic acids such as 3CP by dehalogenases. This is the first report to identify a novel putative β- haloacid dehalogenase that degrades 3CP under ligninolytic and non-ligninolytic conditions. T. asperellum strain SD1, thus has the potential in the development of dehalogenating enzymes for industrial biocatalytic processes, in future.