Recycling of spent oil bleaching earth as source of glycerol for the anaerobic production of acetone, butanol, and ethanol with Clostridium diolis and lipolytic Clostridium lundense

Abstract

A major part of edible oil is subjected to bleaching procedures, primarily with minerals applied as adsorbers. Their recycling is currently done either by regaining the oil via organic solvent extraction or by using the spent bleaching earth (SBE) as additive for animal feed, etc. As a new method, the reutilization of the by‐product SBE for the microbiologic formation of acetone, butanol, and ethanol (ABE) is presented as proof‐of‐concept. The SBE was taken from a palm oil cleaning process. The recycling concept is based on the application of lipolytic clostridia strains. Due to considerably long fermentation times, co‐fermentation with Candida rugosa and enzymatic hydrolyses of the bound oil with a subsequent clostridia fermentation are shown as alternative routes. Anaerobic fermentations under comparison of different clostridia strains were performed with glycerol media, enzymatically hydrolyzed palm oil and SBE. Solutes, side product compositions and productivities were quantified via HPLC. A successful production of ABE solutes from SBE has been done with a yield of 0.15 g butanol per gram of bound glycerol. Thus, the biotechnological recycling of the waste stream is possible in principle. Inhibition of the substrate suspension has been observed. A chromatographic ion‐exchange of substrates increased the biomass concentration.

The effect of spent bleaching earth ageing process on its physicochemical and microbial composition and its potential use as a source of fatty acids and triterpenes

“…The recovered oil from SBE may by use for the production of surfactants, biodegradable polyesters, lubricants, anti-rust products, biofuels (Lara and Park 2004; Park et al 2008; Huang and Chang 2010; Selvabala et al 2011; Pourvosoghi et al 2013) and other chemical compounds (Park and Ming 2004). Tippkötter and co-workers (2014) propose the use of spent bleaching earth as source of glycerol for the anaerobic production of acetone, butanol and ethanol. The possibilities of using the activated SBE as a sorbent of heavy metals are also tested (Seng et al 2001; Wambu et al 2009).…”

“…The fat industry provides substantial quantities of spent bleaching earth (SBE) each year. For example, it is 40,000 t in Poland, 80,000 t in Japan and 1.0–2.0 million t worldwide (Huang and Chang 2010 ; Tippkötter et al 2014 ). This waste material contains from 25 to 40 % oil and various substances being absorbed during bleaching (Beneke and Lagaly 2002 ; Lara and Park 2003 ; Ming et al 2003 ; Kojima et al 2004 ; Park and Ming 2004 ; Krzyśko-Łupicka 2013 ).…”