scholarly journals Upcycling chitin-containing waste into organonitrogen chemicals via an integrated process

2020 ◽  
Vol 117 (14) ◽  
pp. 7719-7728 ◽  
Author(s):  
Xiaoqiang Ma ◽  
Gökalp Gözaydın ◽  
Huiying Yang ◽  
Wenbo Ning ◽  
Xi Han ◽  
...  

Chitin is the most abundant renewable nitrogenous material on earth and is accessible to humans in the form of crustacean shell waste. Such waste has been severely underutilized, resulting in both resource wastage and disposal issues. Upcycling chitin-containing waste into value-added products is an attractive solution. However, the direct conversion of crustacean shell waste-derived chitin into a wide spectrum of nitrogen-containing chemicals (NCCs) is challenging via conventional catalytic processes. To address this challenge, in this study, we developed an integrated biorefinery process to upgrade shell waste-derived chitin into two aromatic NCCs that currently cannot be synthesized from chitin via any chemical process (tyrosine andl-DOPA). The process involves a pretreatment of chitin-containing shell waste and an enzymatic/fermentative bioprocess using metabolically engineeredEscherichia coli. The pretreatment step achieved an almost 100% recovery and partial depolymerization of chitin from shrimp shell waste (SSW), thereby offering water-soluble chitin hydrolysates for the downstream microbial process under mild conditions. The engineeredE. colistrains produced 0.91 g/L tyrosine or 0.41 g/Ll-DOPA from 22.5 g/L unpurified SSW-derived chitin hydrolysates, demonstrating the feasibility of upcycling renewable chitin-containing waste into value-added NCCs via this integrated biorefinery, which bypassed the Haber–Bosch process in providing a nitrogen source.

2020 ◽  
Vol 32 (3) ◽  
pp. 634-640
Author(s):  
Yatim Lailun Ni'mah ◽  
Wemma Devega ◽  
Ita Ulfin ◽  
Harmami Harmami

Mixtures comprising water-soluble chitosan (WSC), agar and different concentrations of sodium lauryl sulphate (SLS) were used to synthesize capsule films. The concentration of agar was fixed at 0.02 %, whereas the concentration (v/v) of SLS varied (0, 0.02, 0.04, 0.06 and 0.08 %). Shrimp shell waste was subjected to demineralization, deproteination and deacetylation to obtain chitosan. The chitosan thus obtained was depolymerized to produce water-soluble chitosan (WSC). Fourier-Transform infrared (FTIR) baseline method was used for calculating the degree of deacetylation of chitosan. FTIR spectra of the obtained capsule film exhibited vibrations of its constituent molecules, namely agar, chitosan and SLS. The elasticity of the film matrix increased with SLS concentrations. In swelling tests conducted using water and 0.1 N HCl, the highest swelling values, 123.74 and 235.87 %, respectively were observed in the capsule film containing 0.08 % SLS in the 10th min. The capsule film containing 0.08 % SLS was degraded (broken) in water and 0.1 N HCl in the 10th and 30th min, respectively. The results indicated that a capsule film containing 0.08% SLS was the most eligible film for commercial use.


Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1887
Author(s):  
Viviana Quintero ◽  
Arturo Gonzalez-Quiroga ◽  
Angel Darío Gonzalez-Delgado

The conservation and proper management of natural resources constitute one of the main objectives of the 2030 Agenda for Sustainable Development designed by the Member States of the United Nations. In this work, a hybrid strategy based on process integration is proposed to minimize freshwater consumption while reusing wastewater. As a novelty, the strategy included a heuristic approach for identifying the minimum consumption of freshwater with a preliminary design of the water network, considering the concept of reuse and multiple pollutants. Then, mathematical programming techniques were applied to evaluate the possibilities of regeneration of the source streams through the inclusion of intercept units and establish the optimal design of the network. This strategy was used in the shrimp shell waste process to obtain chitosan, where a minimum freshwater consumption of 277 t/h was identified, with a reuse strategy and an optimal value of US $5.5 million for the design of the water network.


2016 ◽  
Vol 10 (5) ◽  
pp. 162-174 ◽  
Author(s):  
Trang Si Trung ◽  
Nguyen Thi Khanh Huye ◽  
Nguyen Cong Minh ◽  
Tran Thi Le Trang ◽  
Nguyen The Han

2021 ◽  
Vol 2 (4) ◽  
pp. 286-287
Author(s):  
Alessandra Morana

Every year, the anthropic activities generate thousands of tonnes of agro-industrial residues, which create serious disposal problems and have a very important economic and environmental impact. At this time, the most popular way of their disposing is degradation by biological and/or biochemical and/or thermal treatments; however, they often contain significant percentages of useful compounds that can be extracted and used in several sectors, thus representing an opportunity to be exploited through the development of eco-compatible/sustainable technologies with low environmental impact.


2020 ◽  
Vol 21 (22) ◽  
pp. 8777
Author(s):  
Regina Kutscha ◽  
Stefan Pflügl

Ecological concerns have recently led to the increasing trend to upgrade carbon contained in waste streams into valuable chemicals. One of these components is acetate. Its microbial upgrading is possible in various species, with Escherichia coli being the best-studied. Several chemicals derived from acetate have already been successfully produced in E. coli on a laboratory scale, including acetone, itaconic acid, mevalonate, and tyrosine. As acetate is a carbon source with a low energy content compared to glucose or glycerol, energy- and redox-balancing plays an important role in acetate-based growth and production. In addition to the energetic challenges, acetate has an inhibitory effect on microorganisms, reducing growth rates, and limiting product concentrations. Moreover, extensive metabolic engineering is necessary to obtain a broad range of acetate-based products. In this review, we illustrate some of the necessary energetic considerations to establish robust production processes by presenting calculations of maximum theoretical product and carbon yields. Moreover, different strategies to deal with energetic and metabolic challenges are presented. Finally, we summarize ways to alleviate acetate toxicity and give an overview of process engineering measures that enable sustainable acetate-based production of value-added chemicals.


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