Rhamnolipid (Rh) is a biosurfactant produced by the
bacterial Pseudomonas aeruginosa. This present study investigates
rhizospheric strain C1501 of P. aeruginosa with an accession
number KF976394 with the best production of
rhamnolipid: a biosurfactant. The partially purified rhamnolipid
from strain C1501 and Tween 80 was tested on mycelial
growth of wild strain C1136. The enzyme activities involved
in biodegradation, as well as necrosis induction on the tested
weeds, were performed using scanning electron microscopy. It
was observed that the different concentrations of rhamnolipid
tested enhanced the dry mycelia weight yield of Lasiodiplodia
pseudotheobromae which has been established to be producing
a phytotoxic metabolite for killing weeds. It was observed that
strain C1136 had a high level of cellulase and xylanase enzyme
activities during this study. The scanning electron microscopy
showed that the mutant strain of C1136 combined with 0.003%
v/v of rhamnolipid enhances biodegradability and a high level
of necrosis on the tested weeds compared with that on the
untreated weeds. The highest CMCase activities and xylanase
activities were obtained on the fourth day from the phytotoxic
metabolite produced from the mutant strain of L. pseudo
theobromae when combined with 0.003% v/v of rhamnolipid.
This study has shown that rhamnolipid can serve as an adjuvant
in order to enhance the penetrability of bioherbicide active
ingredient for controlling weeds.