Rambutan (Nephelium lappaceum) production is growing worldwide so the treatment and utilization of Rambutan by-products has become a concern of manufacturers. The objective of this study was to evaluate the potential application of rhizobacteria to decompose Rambutan peel for organic fertilizer production. After the rhizospheric soil samples were selectively proliferated and preadded on agar medium containing only Rambutan peel, the rhizobacterial colony isolates were screened based on their ability to grow on this agar medium and then to degrade cellulose in Rambutan peel. The LD7.3 isolate from the Rambutan rhizosphere showed the highest efficiency in degrading Rambutan peel with 5.6% degraded cellulose content and was identified by the MALDI-TOF technique as belonging to Klebsiella. Klebsiella sp. LD7.3 grew well and maintained the same degrading activity after three times of subculturing in liquid medium. Notably, the supplementation of grinded Rambutan fruit peel to the liquid medium had a positive effect on the growth and the degrading activity of Klebsiella sp. LD7.3. This was the primary report on the application of rhizobacteria to degrade Rambutan peel and the results showed that this was a potential approach to reuse this waste source.

Rhizobacteria have been proved to have potential for biocontrol of fungal phytopathogens and have been successfully applied in the field to a variety of crops. However, diseases caused by Phomopsis longicolla on soybean have been mainly controlled by agricultural or chemical techniques. The objective of this study was to evaluate the in vitro control of rhizobacteria on P. longicolla through their ability to inhibit the growth of P. longicolla on agar plates and disease caused by P. longicolla on soybean seeds. The results showed that the GTC 5.3.84 rhizobacterial isolate was able to inhibit 31% of the growth of P. longicolla GTC 2.5.1 on the agar plate. The GTC 5.3.84 isolate had no effect on germination rate and was able to completely inhibit the disease caused by P. longicolla GTC 2.5.1 on soybean seeds. This result was very clear evidence for the potential application of indigenous rhizobacteria in the control of diseases caused by P. longicolla in soybean. Further studies need to be continued to exploit the efficiency of the GTC 5.3.84 isolate as well as the potential of other indigenous rhizobacteria in the control of P. longicolla disease in soybean.