Rahul Kumar

The bacterial wilt disease caused by Ralstonia solanacearum is an ev er- in creasing threat to tropical as well as t emperat e reg ions of t he world. Though the disease has b een report ed fro m d iffe rent part s of I nd ia, appropriate id ent ificat ion of t he pathogen at molecular level is still inco mplete. In this study we report the isolatio n and molecula r characteriza tion of a R. solanacearum stra in F1C1 f rom wilt ed ch illi p lant collect ed fro m a field nea r Tezpur Un ivers ity, A ssam, I nd ia, u sing te chn iqu es su ch as m u ltiplex PCR, 16S rDNA s equ encing, mult ilocu s typ ing, pathogen i city test, t witching mot i lity and natural t ransformation. Our result s suggest that F1C1 is a phy lo type- I stra in of R. solanacearum s p e c ies comp lex. Add it iona l ly, we a l so r eport pr es enc e of oth er bact er ia l sp ec ie s in t h e oo ze co llected from wilted plants.

Efforts were made to utilize the waste/by-product of two agro-process industries namely pressmud from sugar processing industries and spent yeast from distilleries manufacturing ethanol from cane molasses, for the production of microbial invertase. Our experimentation indicated that these two sources could be ideally utilized for the production of invertase through solid substrate fermentation (SSF). SSF with spent yeast had given highest specific activity of 430 U/mg in 72 h of fermentation. Inoculum percentage of yeast cells on pressmud was optimized as 50% (w/w) with a combination inoculum of spent yeast and fresh cultured yeast at a ratio of 7:3. Crude enzyme was characterized for optimum pH and temperature and maximum activity was recorded at pH 5.0 and at a temperature of 40°C. Impacts of metal ions and detergents on invertase action were studied in which Mn(2+), Fe(3+), Al(3+) and detergents had enhanced the activity of the enzyme whereas Cu(2+) and Zn(2+) inhibited the enzym...