Alkali lignin-degrading Bacillus were isolated from forest soils in China and were identified as Bacillus subtilis TR-03 and Bacillus cereus TR-25 by 16S rDNA sequence analysis. Wherein TR-03 displayed optimal 26.72% alkali lignin (2 g/L) degradation at 7 days and 71.23% of Azure-B (0.01%) decolorization at 36 h of cultivation at 37°C. Ligninolytic enzyme analysis revealed that TR-03 was capable of depolymerizing alkali lignin effectively by the producing of lignin peroxidase and laccase, wherein higher laccase activity was cell-associated. At last, the physical and chemical changes of lignin via SEM and FTIR analysis was further observed to prove the lignin degradation by Bacillus subtilis TR-03.
Cucumber fusarium wilt is a soil-borne disease which causes serious production decrease in cucumber cultivation world widely. Extensive using of chemical pesticides has caused serious environmental pollution and economic losses, therefore, it is particularly urgent to develop efficient, safe and pollution-free biopesticide. In this study, a mutant strain of Trichoderma harzianum cultivated in moso bamboo medium was proved to be an efficient bio-inhibitor of the disease. The mutant strain T. harzianum T334, was obtained by three microwave mutagenesis cycles with an irradiation power of 600 W and irradiation time of 40 s. In contrast to the original strain, the inhibition rate on cucumber fusarium wilt of the strain T334 increased from 63 to 78%. In this work, disk milling pretreatment of moso bamboo has shown significant beneficial effects on both biotransformation and sporulation of T334. Its sporulation reached 3.7 × 109 cfu/g in mushroom bags with 90% bamboo stem powder (pretreated by disk milli), 9.5% bamboo leaf powder and 0.5% wheat bran when the ratio of solid to liquid was 4:6, the inoculum amount was 10%, and the culture temperature was 28°C. These results provide an alternative bioinhibitor for the control of cucumber fusarium wilt, and a potential usage of moso bamboo in the production of microbial pesticide.