Production of Biodegradable Polymer from Agro-Wastes in Alcaligenes sp. and Pseudomonas sp.

R Z Sayyed,S S Shaikh,Hesham Ali El Enshasy,Mohammad F Al Ajmi,Shafiul Haque,S J Wani,Md Tabish Rehman

doi:10.3390/molecules26092443

Abstract

The present study was aimed to evaluate the suitability of agro-wastes and crude vegetable oils for the cost-effective production of poly-β-hydroxybutyrate (PHB), to evaluate growth kinetics and PHB production in Alcaligenes faecalis RZS4 and Pseudomonas sp. RZS1 with these carbon substrates and to study the biodegradation of PHB accumulated by these cultures. Alcaligenes faecalis RZS4 and Pseudomonas sp. RZS1 accumulates higher amounts of PHB corn (79.90% of dry cell mass) and rice straw (66.22% of dry cell mass) medium respectively. The kinetic model suggests that the Pseudomonas sp. RZS1 follows the Monod model more closely than A. faecalis RZS4. Both the cultures degrade their PHB extract under the influence of PHB depolymerase. Corn waste and rice straw appear as the best and cost-effective substrates for the sustainable production of PHB from Alcaligenes faecalis RZS4 and Pseudomonas sp. RZS1. The biopolymer accumulated by these organisms is biodegradable in nature. The agro-wastes and crude vegetable oils are good and low-cost sources of nutrients for the growth and production of PHB and other metabolites. Their use would lower the production cost of PHB and the low-cost production will reduce the sailing price of PHB-based products. This would promote the large-scale commercialization and popularization of PHB as an ecofriendly bioplastic/biopolymer.

Highlights

The bountiful use of non-degradable synthetic polymers has created a frightening scenario for the environment [1]
PHB has been found as an ecofriendly biopolymer, the cost associated with carbon substrate (50% of the overall production) used in the fermentation, has been a major limiting factor in the commercialization of biodegradable polyesters [6,7]
Broths were centrifuged at 10,000 rpm for 10 min and the cell mass of these cultures were grown at 30 ◦C at 120 rpm for 48 h in the PHB accumulation nitrogen-deficient medium (NDM) containing (g/L), Na2HPO4, 3.8; KH2PO4, 2.65; NH4Cl, 2.0; MgSO4, 0.2; fructose, 2.0; EDTA, 5.0; ZnSO4. 7H2O, 2.2; CaCl2, 5.45; MnCl2. 6H2O, 5.06; H3BO3, 0.05; FeSO47H2O, 4.79; NH4Mo, 24.4; CoCl2.6H2O, 1.6; and CuSO45H2O, 1.57 [54]

Summary

Introduction

The bountiful use of non-degradable synthetic polymers has created a frightening scenario for the environment [1]. The environmental and health concerns brought poly-β-hydroxybutyrate (PHB) as sustainable and the best alternative to synthetic plastic and an ideal material for making biodegradable plastics [2,3]. It is completely biodegradable in a natural environment after disposal [4,5]. PHB production from low-cost and renewable carbon sources like industrial wastes such malt, soya, sesame, molasses, bagasse, coconut pulp, and pharmaceutical waste have reviewed and reported [13].

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Discussion

Conclusion