Strategies for valorisation of wastes from bioethanol production lactic acid and probiotics as added value products

Transcription

1 CYPRUS th International Conference on Sustainable Solid Waste Management Strategies for valorisation of wastes from bioethanol production lactic acid and probiotics as added value products A. Djukić-Vuković 1 *, D. Mladenović 1, J. Pejin 2, L. Mojović 1 1 Faculty of Technology and Metallurgy, University of Belgrade 2 Faculty of Technology, University of Novi Sad *adjukic@tmf.bg.ac.rs

2 Stillage is a by product of bioethanol production on different substrates (corn, triticale, waste bread...). What about advanced bioethanol bioethanol produced on wastes and residues? to 0.5% - advanced biofuels is target - EU Indirect land use change directive (April 2015) Competitiveness of bioethanol as a alternative fuel is dependent on the environmentally friendly and economically feasible management of residues remaining after production process

3 Why lactic acid? Lactic acid (2-hydroxypropanoic acid) is widely used chemical in food, pharmaceutical and chemical industry 7% annual growth rate. High demand for lactic acid is driven by increased production of polylactides (PLA, PLGA) - biocompatible polymers used for medical, pharmaceutical and food industry purposes. Specially attractive LA for PLA produced from renewable sources. Fermentation enables selective production of L or D isomer. WHO: Probiotics are microorganism with beneficial effect on health of host human or animal 10

4 Aim: Lactic acid production on thin stillage Fermentation media sterilized liquid wasted bread, liquid molasses stillage and liquid corn stillage from bioethanol plant Reahem and Alpis, Serbia, initial sugar concentration was set at approximately 25 g/l Table 1. Chemical composition of different stillages Thin corn stillage Thin molasses stillage Thin wasted bread stillage Reducing carbohydrates (g L -1 ) ± ± ± 0.68 Crude protein (g L -1 ) 8.42 ± ± ± 1.10 Ash (g L -1 ) 2.90 ± ± ± 0.23 Lipids (g L -1 ) 1.83 ± ± ± 0.81 Dry matter (%) 5.02 ± ± ± 0.48 Fermentation Batch, shaking of 90 rpm, 5% (v/v) inoculum concentration 41 C, microaerophylic, ph control: without and with addition of neutralizing agents (CaCO 3, 30% NaOH in 4h intervals) Microorganism Lactobacillus rhamnosus ATCC 7469 homofermentative, > 97% L(+)-lactic acid

5 25 thin wasted bread stillage thin molassed stillage thin corn stillage Lactic acid concentration (g L -1 ) log N (CFU ml -1 ) Time (h) Time (h) The highest LA concentration - thin wasted bread stillage

6 Table 2. LA fermentation parameters LA concentration (g L -1 ) LA yield (g g -1 ) LA yield coefficient (g g -1 ) LA productivity (g L -1 h -1 ) Thin corn stillage ± ± ± ± 0.02 Thin molasses stillage ± ± ± ± 0.02 Thin wasted bread stillage ± ± ± ± 0.02 biomass 18 CaCO 3 10 lactic acid Lactic acid concentration (g L -1 ) LogN (CFU ml -1 ) 0 1% CaCO3 2% CaCO3 5% CaCO3 10% CaCO3 5

7 20 18 Thin wasted bread stillage Lactic acid concentration (g L -1 ) NaOH CaCO 3 NaOH in 4h intervals LA yield 0.77 g g -1 LA productivity 1.14 g L -1 h -1 Biomass CFU ml Time (h) L. rhamnosus ATCC 7469 has the probiotic characteristics!

8 WHOLE STILLAGE HIGH GRAVITY STILLAGE (HGS) SEPARATION Solid fraction of fermentation media with L. rhamnosus Feed ATCC for 7469 biomass monogastric animals LA fermentation of HGS FEED WITH PROBIOTIC BIOMASS LACTIC ACID FERMENTATION with free L. rhamnosus SEPARATION Process I Hemicellulose 4.01% Liquid fraction of fermentation media with LA Lactic acid extraction Nitrogen-free extract, 49.35% THIN STILLAGE (TS) LA fermentation PROBIOTICS of TS Crude with immobilized fibres; L. rhamnosus 2,04% Proteins, SEPARATION40.24% Solid fraction - L. rhamnosus immobilized onto zeolite PROBIOTIC- ZEOLITE Lipids; 4,92% ADDITIVE FOR FEED Ash; 0,35% Process II SOLID PART OF STILLAGE DRYING FEED (DDG DRIED DESTILLER S GRAINS ) Liquid fraction of fermentation media with LA Lactic acid extraction

9 Other possibilities... 4th International Conference on Sustainable Solid Waste Management, Limassol, Cyprus, June 2016 WHOLE STILLAGE HIGH GRAVITY STILLAGE (HGS) SEPARATION LA fermentation of HGS with free L. rhamnosus SEPARATION THIN STILLAGE (TS) LA fermentation of TS with immobilized L. rhamnosus SOLID PART OF STILLAGE DRYING Solid fraction of fermentation media with L. rhamnosus ATCC 7469 biomass FEED WITH PROBIOTIC BIOMASS Liquid fraction of fermentation media with LA Lactic acid extraction SEPARATION Solid fraction - L. rhamnosus immobilized onto zeolite PROBIOTIC- ZEOLITE ADDITIVE FOR FEED FEED (DDG DRIED DESTILLER S GRAINS ) Liquid fraction of fermentation media with LA Lactic acid extraction Process I Process II

10 Conclusions Stillages from advanced bioethanol production have shown same or better characteristics than stillage from 1 st generation bioethanol as substrates for LAF. Thin wasted bread stillage with ph control (NaOH in 4h intervals) -process productivity was improved twofold. Added value products: Probiotic biomass >10 9 CFU ml -1 Animal feed monogastric animals

11 Acknowledgement This work was funded by Ministry of education, science and technological development, Republic of Serbia, Project number TR Thank you for attention! Faculty of Technology and Metallurgy, University of Belgrade