Biodegradation of shrimp processing bio-waste and concomitant production of chitinase enzyme and N-acetyl-D-glucosamine by marine bacteria: production and process optimization.

A total of 250 chitinolytic bacteria from 68
different marine samples were screened employing
enrichment method that utilized native chitin as the sole
carbon source. After thorough screening, five bacteria were
selected as potential cultures and identified as; Stenotrophomonas
sp. (CFR221 M), Vibrio sp. (CFR173 M),
Phyllobacteriaceae sp. (CFR16 M), Bacillus badius
(CFR198 M) and Bacillus sp. (CFR188 M). All five strains
produced extracellular chitinase and GlcNAc in SSF using
shrimp bio-waste. Scanning electron microscopy confirmed
the ability of these marine bacteria to adsorb onto solid
shrimp bio-waste and to degrade chitin microfibers. HPLC
analysis of the SSF extract also confirmed presence of
36–65 % GlcNAc as a product of the degradation. The
concomitant production of chitinase and GlcNAc by all
five strains under SSF using shrimp bio-waste as the solid
substrate was optimized by ‘one factor at a time’ approach.
Among the strains, Vibrio sp. CFR173 M produced significantly
higher yields of chitinase (4.8 U/g initial dry
substrate) and GlcNAc (4.7 lmol/g initial dry substrate) as
compared to other cultures tested. A statistically designed
experiment was applied to evaluate the interaction of
variables in the biodegradation of shrimp bio-waste and
concomitant production of chitinase and GlcNAc by Vibrio
sp. CFR173 M. Statistical optimization resulted in a twofold
increase of chitinase, and a 9.1 fold increase of
GlcNAc production. These results indicated the potential of
chitinolytic marine bacteria for the reclamation of shrimp
bio-waste, as well as the potential for economic production
of chitinase and GlcNAc employing SSF using shrimp biowaste
as an ideal substrate.