Nimisha R. Nair

Bio: Nimisha R. Nair is an academic researcher from National Institute for Interdisciplinary Science and Technology. The author has contributed to research in topics: Biodegradation & Polylactic acid. The author has an hindex of 7, co-authored 8 publications receiving 1866 citations.

Biodegradation of Biopolymers

Abstract: The concept of biodegradable plastics is receiving significant attention with respect to solid waste accumulation. Enormous efforts have been made in revolutionizing degradable biological materials without any environmental pollution to substitute for oil-based traditional plastics. With the overuse of plastics and increasing pressure being placed on capacities available for plastic waste disposal, the requirement for biodegradable plastics and biodegradation of plastic wastes has obtained immense importance in recent years. Awareness of the impact on the environmental waste problem has awakened research in the area of degradable polymers. Considering the emerging environmental issues, the demand to develop a material that does not burden nature has increased. It is essential to study the microbial degradation of biopolymers to understand what is necessary for biodegradation and the mechanisms involved. Widespread investigations on the biodegradation of plastics have been carried out to overcome the environmental problems associated with synthetic plastic waste. This chapter provides an overview of the degradation mechanisms of biodegradable polymers with particular emphasis on the main parameters affecting the degradation of polymeric biomaterials.

Augmentation of a Microbial Consortium for Enhanced Polylactide (PLA) Degradation

Abstract: Bioplastics are eco-friendly and derived from renewable biomass sources. Innovation in recycling methods will tackle some of the critical issues facing the acceptance of bioplastics. Polylactic acid (PLA) is the commonly used and well-studied bioplastic that is presumed to be biodegradable. Considering their demand and use in near future, exploration for microbes capable of bioplastic degradation has high potential. Four PLA degrading strains were isolated and identified as Penicillium chrysogenum, Cladosporium sphaerospermum, Serratia marcescens and Rhodotorula mucilaginosa. A consortium of above strains degraded 44 % (w/w) PLA in 30 days time in laboratory conditions. Subsequently, the microbial consortium employed effectively for PLA composting.

Conversion of biomass to selected chemical products

Abstract: This critical review provides a survey illustrated by recent references of different strategies to achieve a sustainable conversion of biomass to bioproducts. Because of the huge number of chemical products that can be potentially manufactured, a selection of starting materials and targeted chemicals has been done. Also, thermochemical conversion processes such as biomass pyrolysis or gasification as well as the synthesis of biofuels were not considered. The synthesis of chemicals by conversion of platform molecules obtained by depolymerisation and fermentation of biopolymers is presently the most widely envisioned approach. Successful catalytic conversion of these building blocks into intermediates, specialties and fine chemicals will be examined. However, the platform molecule value chain is in competition with well-optimised, cost-effective synthesis routes from fossil resources to produce chemicals that have already a market. The literature covering alternative value chains whereby biopolymers are converted in one or few steps to functional materials will be analysed. This approach which does not require the use of isolated, pure chemicals is well adapted to produce high tonnage products, such as paper additives, paints, resins, foams, surfactants, lubricants, and plasticisers. Another objective of the review was to examine critically the green character of conversion processes because using renewables as raw materials does not exempt from abiding by green chemistry principles (368 references).

Physical and mechanical properties of PLA, and their functions in widespread applications — A comprehensive review

Abstract: Poly(lactic acid) (PLA), so far, is the most extensively researched and utilized biodegradable aliphatic polyester in human history. Due to its merits, PLA is a leading biomaterial for numerous applications in medicine as well as in industry replacing conventional petrochemical-based polymers. The main purpose of this review is to elaborate the mechanical and physical properties that affect its stability, processability, degradation, PLA-other polymers immiscibility, aging and recyclability, and therefore its potential suitability to fulfill specific application requirements. This review also summarizes variations in these properties during PLA processing (i.e. thermal degradation and recyclability), biodegradation, packaging and sterilization, and aging (i.e. weathering and hygrothermal). In addition, we discuss up-to-date strategies for PLA properties improvements including components and plasticizer blending, nucleation agent addition, and PLA modifications and nanoformulations. Incorporating better understanding of the role of these properties with available improvement strategies is the key for successful utilization of PLA and its copolymers/composites/blends to maximize their fit with worldwide application needs.