Xylitol is a high value sugar alcohol with anticariogenic properties that is used as an ideal sweetener for diabetic patients. Industrially, xylitol is manufactured by catalytic reduction of pure xylose, which has
some disadvantages. The fermentation process has been studied as an alternative, but its viability is dependent on the optimization of several variables. This fermentation process on an industrial-scale is not feasible due to decreased productivity. Compared to the fermentation process, enzymatic method is expected to make a substantial increase in productivity. Enzymatic xylitol production from xylose exist in lignocellulosics is an attractive and promising alternative method to the chemical process. The enzymatic method might be able to overcome the disadvantages of the chemical process. This article reviews the literature on the processes for xylitol production and identifies further ways for improved xylitol production to compete with the current chemical process.
The increase in the price of commercial succinic acid has necessitated the need for its
synthesis from waste materials such as glycerol. Glycerol residue is a waste product of
Oleochemical production which is cheaply available and a very good source of carbon.
The use of immobilized cells can further reduce the overall cost of the production process.
This study primarily aims to produce succinic acid from glycerol residue through the use
of immobilized Escherichia coli in a batch fermentation process. The parameters which
affect bacterial fermentation process such as the mass substrate, temperature, inoculum
size and duration of fermentation were screened using One-Factor-At-a-Time (OFAT)
method. The result of the screening process shows that a substrate (glycerol) concentration
of 30 g, inoculum size 20% v/v, and time 4 h produced the maximum succinic acid
concentration of 117.99 g/L. The immobilized cells were found to be stable as well as
retain their fermentative ability up to the 6th cycle of recycling, thereby presenting as an
advantage over the free cell system. Therefore, conclude that using immobilized cells can
contribute immensely to the cost-effective production of succinic acid from glycerol
residue.