Page 76 - Refining Biomass Residues for Sustainable Energy and Bioproducts

Microbial-derived natural 3

bioproducts for a sustainable
environment: a bioprospective

for waste to wealth

Juhi Gupta, Rashmi Rathour*, Kristina Medhi*, Bhawna Tyagi*
and Indu Shekhar Thakur
School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India

3.1 Introduction

Microorganisms are never prominently available as single dispersed cells but as
polymicrobial aggregates. These microbial aggregates are termed as biopolymers,
which are formed by biological systems and can be in various forms like biofilms,
flocs, mats, etc. (Flemming and Wingender, 2010). The history of biopolymers
dates back to the middle of 19th century when dextran was discovered by Louis
Pasteur, which was soon followed by many others. They are environmentally effec-
tive and cost-friendly alternatives to provide sustainable solutions to the uprising
problems (More et al., 2014). Microbes produce two types of polymers:
Extracellular (secreted outside the cell) and intracellular (synthesized inside the
cell) polymers using different carbon sources. A large variety of ecological taxa
including bacteria, fungi, and algae are capable of producing biopolymers com-
posed of different monomeric units. They serve a varied range of functions and
important properties which makes them suitable enough for the industrial and bio-
medical sector. New research avenues are searched to perform rational engineering
on the present microbes which will open the possibility not only for the better pro-
duction of natural polymers but also the production for some unnatural and artificial
polymers with efficient applications (Rehm, 2010). The molecular and regulatory
processes governing the production should be known to efficiently alter it the
required way.
The broad classification of biopolymers groups them into four categories as
follows:

1. Polyesters: Polymers having ester functional group in their main chain. Example:
Polybutyrate, polyhydroxyalkanoate (PHA), and poly(β-malate).

These authors contributed equally.
Refining Biomass Residues for Sustainable Energy and Bioproducts. DOI: https://doi.org/10.1016/B978-0-12-818996-2.00003-X
© 2020 Elsevier Inc. All rights reserved.