Phenol oxidase producing bacteria from shrimp

Abstract

Phenol oxidases are the group of enzymes with multifunctional abilities. The presence of bacteria with the extracellular phenol oxidase production in the melanised appendages of Litopenaeus vannamei was studied. Market drawn samples of Litopenaeus vannamei with melanisation were checked for possible intervention of bacteria with phenol oxidase production. Positive and negative screening with tyrosine yielded four types of bacteria with maximum phenol oxidase production. The bacteria were purified and named as TMA7, TMA9, TMA10 and TMA12. The sequencing of 16s rRNA fragment of the isolates revealed that TMA7 as Bacillus niabensis, TMA9 as Acinetobacter spp., TMA10 as Bacillus megaterium and TMA 12 as Providencia rustigans. Tyrosinase positive cultures were inoculated in the liquid medium and incubated at 37 degree celsius for 72 h at 170 rpm. After three days, the crude supernatant samples served as a source of enzyme for tyrosinase activity. The tyrosinase activity analyzed with dynamic reader in the presence of L-DOPA, L tyrosine for Diphenolase and mono phenolase respectively. TMA12 has shown 3.36 units of enzyme production in 3 days. TMA 10 has shown 2.99 units of enzyme production in 3 days. This study asks for further investigations on role of tyrosinase producing bacteria in shrimp