| Summary: | Submitted in complete fulfilment for the Degree of Master of Technology: Biotechnology, Durban University of Technology, 2013. === The continual growth of the global biodiesel industry has resulted in a
proportional increase in crude glycerol production. The by-production of
glycerol waste during the manufacture of biodiesel has, with recent research,
proven to hold use as a feedstock for the production of several commodity
chemicals. The conversion of glycerol may be carried out by both chemical as
well as biological means. The biological conversion of glycerol surpasses
chemical conversion with respect to higher yield and selectivity, normal
reaction conditions and the use of cheaper biological catalysts. Many
microorganisms are known to convert glycerol to different value added
products. This study involved the isolation of bacteria from soil and crude
glycerol from a local biodiesel plant. Isolates were then used to convert crude
glycerol supplemented with salts and a nitrogen source into commercially
viable products. Isolates which successfully degraded glycerol were then
identified via 16S PCR. A strain of Klebsiella pneumoniae, which is a known
producer of 1,3-propanediol (1,3-PDO), was isolated from soil and two strains
of Sphingomonas sp., which is a known gellan producer, was isolated from
biodiesel waste. Gellan is an exopolysaccharide used in the food, cosmetic
and pharmaceutical industries sold commercially as a product known as
Gelrite or Gelzan while 1,3-PDO is an important component of fuels and
polyesters (used widely in the petroleum industry) and is currently chemically
produced. Using crude glycerol for producing 1,3-PDO is a good solution from
an economic as well as ecological point of view. K. pneumoniae,
Sphingomonas psueudosanguinis and Sphingomonas yabuuchiae were
subjected to a series of shake flask fermentations in order to determine
optimal growth conditions. This microoganism was able to successfully
produce significant amounts of 1,3-PDO and lactic acid using crude glycerol
(80
g/l),
without
pre-treatment
(37
and
6.8
g/l
respectively).
S
psueudosanguinis and S. yabuuchiae were both able to produce two of the
highest amounts of gellan gum than that reported by other studies using crude
glycerol (80 g/l) as a sole carbon source in a minimal medium (50.9 and 52.6
g/l respectively).
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