Cargando…

Bioflocculant production from untreated corn stover using Cellulosimicrobium cellulans L804 isolate and its application to harvesting microalgae

BACKGROUND: Microalgae are widely studied for biofuel production. Nevertheless, harvesting step of biomass is still a critical challenge. Bioflocculants have been applied in numerous applications including the low-cost harvest of microalgae. A major bottleneck for commercial application of biofloccu...

Descripción completa

Detalles Bibliográficos
Autores principales: Liu, Weijie, Zhao, Chenchu, Jiang, Jihong, Lu, Qian, Hao, Yan, Wang, Liang, Liu, Cong
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4617488/
https://www.ncbi.nlm.nih.gov/pubmed/26500696
http://dx.doi.org/10.1186/s13068-015-0354-4
_version_ 1782396804198825984
author Liu, Weijie
Zhao, Chenchu
Jiang, Jihong
Lu, Qian
Hao, Yan
Wang, Liang
Liu, Cong
author_facet Liu, Weijie
Zhao, Chenchu
Jiang, Jihong
Lu, Qian
Hao, Yan
Wang, Liang
Liu, Cong
author_sort Liu, Weijie
collection PubMed
description BACKGROUND: Microalgae are widely studied for biofuel production. Nevertheless, harvesting step of biomass is still a critical challenge. Bioflocculants have been applied in numerous applications including the low-cost harvest of microalgae. A major bottleneck for commercial application of bioflocculant is its high production cost. Lignocellulosic substrates are abundantly available. Hence, the hydrolyzates of rice stover and corn stover have been used as carbon source to produce the bioflocculant in previous studies. However, the hydrolyzates of biomass required the neutralization of pH before the downstream fermentation processes, and the toxic by-products produced during hydrolysis process inhibited the microbial activities in the subsequent fermentation processes and contaminated the bioflocculant product. Therefore, strains that can secrete plant cell-wall-degrading enzymes and simultaneously produce bioflocculants through directly degrading the lignocellulosic biomasses are of academic and practical interests. RESULTS: A lignocellulose-degrading strain Cellulosimicrobium cellulans L804 was isolated in this study, which can produce the bioflocculant MBF-L804 using untreated biomasses, such as corn stover, corn cob, potato residues, and peanut shell. The effects of culture conditions including initial pH, carbon source, and nitrogen source on MBF-L804 production were analyzed. The results showed that over 80 % flocculating activity was achieved when the corn stover, corn cob, potato residues, and peanut shell were used as carbon sources and 4.75 g/L of MBF-L804 was achieved under the optimized condition: 20 g/L dry corn stover as carbon source, 3 g/L yeast extract as nitrogen source, pH 8.2. The bioflocculant MBF-L804 contained 68.6 % polysaccharides and 28.0 % proteins. The Gel permeation chromatography analysis indicated that the approximate molecular weight (MW) of MBF-L804 was 229 kDa. The feasibility of harvesting microalgae Chlamydomonas reinhardtii and Chlorella minutissima using MBF-L804 was evaluated. The highest flocculating efficiencies for C. reinhardtii and C. minutissima were 99.04 and 93.83 %, respectively. CONCLUSIONS: This study shows for the first time that C. cellulans L804 can directly convert corn stover, corn cob, potato residues and peanut shell into the bioflocculants, which can be used to effectively harvest microalgae. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13068-015-0354-4) contains supplementary material, which is available to authorized users.
format Online
Article
Text
id pubmed-4617488
institution National Center for Biotechnology Information
language English
publishDate 2015
publisher BioMed Central
record_format MEDLINE/PubMed
spelling pubmed-46174882015-10-24 Bioflocculant production from untreated corn stover using Cellulosimicrobium cellulans L804 isolate and its application to harvesting microalgae Liu, Weijie Zhao, Chenchu Jiang, Jihong Lu, Qian Hao, Yan Wang, Liang Liu, Cong Biotechnol Biofuels Research BACKGROUND: Microalgae are widely studied for biofuel production. Nevertheless, harvesting step of biomass is still a critical challenge. Bioflocculants have been applied in numerous applications including the low-cost harvest of microalgae. A major bottleneck for commercial application of bioflocculant is its high production cost. Lignocellulosic substrates are abundantly available. Hence, the hydrolyzates of rice stover and corn stover have been used as carbon source to produce the bioflocculant in previous studies. However, the hydrolyzates of biomass required the neutralization of pH before the downstream fermentation processes, and the toxic by-products produced during hydrolysis process inhibited the microbial activities in the subsequent fermentation processes and contaminated the bioflocculant product. Therefore, strains that can secrete plant cell-wall-degrading enzymes and simultaneously produce bioflocculants through directly degrading the lignocellulosic biomasses are of academic and practical interests. RESULTS: A lignocellulose-degrading strain Cellulosimicrobium cellulans L804 was isolated in this study, which can produce the bioflocculant MBF-L804 using untreated biomasses, such as corn stover, corn cob, potato residues, and peanut shell. The effects of culture conditions including initial pH, carbon source, and nitrogen source on MBF-L804 production were analyzed. The results showed that over 80 % flocculating activity was achieved when the corn stover, corn cob, potato residues, and peanut shell were used as carbon sources and 4.75 g/L of MBF-L804 was achieved under the optimized condition: 20 g/L dry corn stover as carbon source, 3 g/L yeast extract as nitrogen source, pH 8.2. The bioflocculant MBF-L804 contained 68.6 % polysaccharides and 28.0 % proteins. The Gel permeation chromatography analysis indicated that the approximate molecular weight (MW) of MBF-L804 was 229 kDa. The feasibility of harvesting microalgae Chlamydomonas reinhardtii and Chlorella minutissima using MBF-L804 was evaluated. The highest flocculating efficiencies for C. reinhardtii and C. minutissima were 99.04 and 93.83 %, respectively. CONCLUSIONS: This study shows for the first time that C. cellulans L804 can directly convert corn stover, corn cob, potato residues and peanut shell into the bioflocculants, which can be used to effectively harvest microalgae. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13068-015-0354-4) contains supplementary material, which is available to authorized users. BioMed Central 2015-10-20 /pmc/articles/PMC4617488/ /pubmed/26500696 http://dx.doi.org/10.1186/s13068-015-0354-4 Text en © Liu et al. 2015 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research
Liu, Weijie
Zhao, Chenchu
Jiang, Jihong
Lu, Qian
Hao, Yan
Wang, Liang
Liu, Cong
Bioflocculant production from untreated corn stover using Cellulosimicrobium cellulans L804 isolate and its application to harvesting microalgae
title Bioflocculant production from untreated corn stover using Cellulosimicrobium cellulans L804 isolate and its application to harvesting microalgae
title_full Bioflocculant production from untreated corn stover using Cellulosimicrobium cellulans L804 isolate and its application to harvesting microalgae
title_fullStr Bioflocculant production from untreated corn stover using Cellulosimicrobium cellulans L804 isolate and its application to harvesting microalgae
title_full_unstemmed Bioflocculant production from untreated corn stover using Cellulosimicrobium cellulans L804 isolate and its application to harvesting microalgae
title_short Bioflocculant production from untreated corn stover using Cellulosimicrobium cellulans L804 isolate and its application to harvesting microalgae
title_sort bioflocculant production from untreated corn stover using cellulosimicrobium cellulans l804 isolate and its application to harvesting microalgae
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4617488/
https://www.ncbi.nlm.nih.gov/pubmed/26500696
http://dx.doi.org/10.1186/s13068-015-0354-4
work_keys_str_mv AT liuweijie bioflocculantproductionfromuntreatedcornstoverusingcellulosimicrobiumcellulansl804isolateanditsapplicationtoharvestingmicroalgae
AT zhaochenchu bioflocculantproductionfromuntreatedcornstoverusingcellulosimicrobiumcellulansl804isolateanditsapplicationtoharvestingmicroalgae
AT jiangjihong bioflocculantproductionfromuntreatedcornstoverusingcellulosimicrobiumcellulansl804isolateanditsapplicationtoharvestingmicroalgae
AT luqian bioflocculantproductionfromuntreatedcornstoverusingcellulosimicrobiumcellulansl804isolateanditsapplicationtoharvestingmicroalgae
AT haoyan bioflocculantproductionfromuntreatedcornstoverusingcellulosimicrobiumcellulansl804isolateanditsapplicationtoharvestingmicroalgae
AT wangliang bioflocculantproductionfromuntreatedcornstoverusingcellulosimicrobiumcellulansl804isolateanditsapplicationtoharvestingmicroalgae
AT liucong bioflocculantproductionfromuntreatedcornstoverusingcellulosimicrobiumcellulansl804isolateanditsapplicationtoharvestingmicroalgae