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.com
Volume 7, Issue 4 (Suppl)
J Biotechnol Biomater, an open access journal
ISSN: 2155-952X
Bio America 2017
October 19-20, 2017
October 19-20, 2017 | New York, USA
18
th
Biotechnology Congress
Inulin conversion towards fructose or lactic acid by Mn2+ mediated metabolic flux in
Lactobacillus
paracasei
Kaloyan K Petrov, Luiza G Popova, Petya V Velikova
and
Penka M Petrova
Institute of Microbiology, BAS, Bulgaria
P
resuming the important role of cations in carbohydrate metabolism, sugars transport, and potentially, in the regulation of genes
transcription levels, it may be expected that they would exert a significant influence on inulin conversion by
L. paracasei
. The aim
of this study was to obtain maximal amounts of two valuable bio-chemicals: lactic acid and fructose, by engagement of bivalent metal
ions as a new instrumentality to govern the process of inulin conversion. The kinetics of batch processes of direct inulin conversion
to LA showed that Mn2+addition accelerated the inulin hydrolysis and sugars consumption by allosteric activation of inulinase and
enhancement of the glycolytic flux. The highest LA concentration was reached by 15 mMMn2+ addition - 151 g/L, corresponding to
40% increase, with yield 0.83 g/g substrate. This LA amount is the highest ever obtained from inulin and discloses the role of Mn2+ as
a powerful tool for LA production intensification. On the other hand, the exclusion of bivalent metal ions led to elevated expression
of fosE gene, encoding fructan-ß-fructosidase - the key enzyme for inulin hydrolysis. Thus, if the process of inulin conversion is
conducted by fed-batch fermentation mode (providing substrate excess) and in medium devoid of salts and microelements, maximal
fructose concentrations could be achieved. During such process total amountof 675 g inulin was hydrolyzed, giving rise to formation
of359 g/L fructose, along with 55.2 g/L LA, 34.8 g/L glucose,17.9 g/L sucrose, and about 25 g/L oligo sugars. In conclusion, the present
study is the first that reveals the important role of bivalent cations on the overall process of inulin fermentation by
Lactobacilli.
The
obtained fructose concentration is the highest ever received during microbial process (36% solution), allowing the developmentof a
novel approach for fructose production via microbial fermentation of inulin.
Biography
Kaloyan K Petrov is the Head of the Department of Chemical and Biochemical Reactors in the Institute of Chemical Engineering, Bulgarian Academy of Sciences. His work
is devoted to optimization of downstream processes by the techniques of bioprocess and metabolic engineering. His team develops biotechnologies for microbial produc-
tion of platform chemicals and fuels by conversion of waste or renewable energy resources, including the cutting-edge biotechnologies for 2,3-Butanediol production from
glycerol and starch by the use of natural and recombinant strains, and novel bio-processes for lactic acid synthesis by utilization of starch and inulin. Other topics of his work
are the fermentative production of enzymes and valuable chemicals in respect of their industrial application, strain’s improvement by gene engineering, microbiological and
molecular biological tools, development and analysis of probiotics and prebiotics
kaloian04@yahoo.comKaloyan K Petrov et al., J Biotechnol Biomater 2017, 7:4 (Suppl)
DOI: 10.4172/2155-952X-C1-080