Biotechnological Applications of Hemicellulosic Derived Sugars: State-of-the-Art - Sustainable Biotechnology: Sources of Renewable Energy - page 82

production yields of the desired titers on a commercial scale. Genetic engineering
may also improve microbial efficiency for the overproduction of industrial prod-
ucts using cheaper sources of carbohydrates in fermentation media, the hallmark
of commercial fermentation processes. The microbes will be more useful if they
have characteristics such as thermotolerance, alkalotolerance, or tolerance of other
extreme conditions.
Hemicellulose degradation into fermentable sugars is another area where the
scope of research seems enormous. Efforts are underway at our laboratory for the
production of ethanol and xylitol from lignocellulose feedstock. Multiple research
projects are being sponsored by government agencies to improve the pretreatment
process of lignocellulosics for their conversion into ethanol and xylitol [24, 63-69].
In the last five years, there has been comparatively less research into 2, 3-BD pro-
duction than into ethanol and xylitol production worldwide. New research insights,
such as the development of transgenic plants containing less lignin, may be help-
ful for the conversion of biomass into value-added products. Chen and Dixon [70]
developed antisense-mediated down-regulation of lignin biosynthesis in alfalfa to
reduce or eliminate the need for pretreatment. This may make the hemicellulosic
fraction more accessible due to the reduced presence of lignin, which in turn will
require a milder pretreatment and less enzymatic load to get the desired yield
of fermentable sugars. Releasing genetically engineered plants may raise ethical
issues among environmentalists; however, it can be assumed that the generation
of new products from hemicellulose will strengthen the economy by saving for-
eign exchange reserves and promoting energy independence, which will benefit the
environment.
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