Location: Renewable Product Technology ResearchTitle: Fermentative production of butyric acid from paper mill sludge hydrolysates using Clostridium tyrobutyricum NRRL B-67062/RPT 4213
Submitted to: Biocatalysis and Agricultural Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/2/2018
Publication Date: 2/7/2018
Citation: Liu, S., Duncan, S., Qureshi, N., Rich, J.O. 2018. Fermentative production of butyric acid from paper mill sludge hydrolysates using Clostridium tyrobutyricum NRRL B-67062/RPT 4213. Biocatalysis and Agricultural Biotechnology. 14:48-51. https://doi.org/10.1016/j.bcab.2018.02.002.
Interpretive Summary: Butyric acid is a short-chain fatty acid that is used as flavoring agents in feeds and foods, and is also incorporated into perfumes, pharmaceuticals, plastics and textile auxiliaries. Butyric acid has been produced via a petrochemical route, but the biological production of butyric acid addresses sustainability concerns and satisfies consumer preferences when used as food additives or cosmetic products. The pulp and paper making process produces about 300–350 million tons of paper mill sludge (PMS) every year, which is an economic burden and also an environmental concern since the majority of the PMS is disposed of by landfill. This paper reported the fermentative production of butyric acid from paper mill waste and the results can be used to study cost effective renewable production of butyric acid from paper mill waste in large scales.
Technical Abstract: The pulp and paper industry produces about 300-350 million tons of paper mill sludge (PMS) annually and the majority of this waste is disposed of by landfill. PMS contains up to 75% carbohydrates, which potentially serve as a fermentable carbon source. In this study, we adapted an efficient method of de-ashing and fiber regeneration process, followed by enzymatic hydrolysis of PMS. The glucose released from PMS was used for butyric acid production through anaerobic fermentations using Clostridium tyrobutyricum B-67062/RPT 4213. To reduce production cost, we screened 9 different media and found that 8.52 and 8.35 gL-1 butyric acid was produced from 4 liter batch fermentation in MRS and RCM4 medium, respectively. Moreover, nearly 7 gL-1 butyric acid was produced by using PMS hydrolysates from two different mills when combined with a fraction of MRS, and over 6 gL-1 butyric acid was produced from hydrolysate combined with a fraction of the relatively cheaper RCM4 medium. This study suggested that beside agricultural lignocellulosic biomass feedstocks, low valued waste materials from the pulp and paper industries could also be used for the sustainable production of butyric acid.