Lactic Acid Production from Non-Edible Biomass and the Development of Poly（Lactic Acid）Diols as Building Blocks of Various Functional Polymers

Lactic acid has been shown to have the most promising application in biomaterials as poly(lactic acid).L. rhamnosusATCC 10863 that produces L-lactic acid was used to perform the fermentation and molasses was used as substrate. A solution containing 27.6 g/L of sucrose (main composition of molasses) and 3.0 g/L of yeast extract was prepared, considering the final volume of 3,571 mL (14.0% (v/v) inoculum). Batch and fed batch fermentations were performed with temperature of 43.4°C and pH of 5.0. At the fed batch, three molasses feed were applied at 12, 24, and 36 hours. Samples were taken every two hours and the amounts of lactic acid, sucrose, glucose, and fructose were determined by HPLC. The sucrose was barely consumed at both processes; otherwise the glucose and fructose were almost entirely consumed. 16.5 g/L of lactic acid was produced at batch and 22.0 g/L at fed batch. Considering that lactic acid was produced due to the low concentration of the well consumed sugars, the final amount was considerable. The cell growth was checked and no substrate inhibition was observed. A sucrose molasses hydrolysis is suggested to better avail the molasses fermentation with this strain, surely increasing the L-lactic acid.

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Opportunities, perspectives and limits in lactic acid production from waste and industrial by-products

Hemijska industrija ◽

10.2298/hemind150403050m ◽

2016 ◽

Vol 70 (4) ◽

pp. 435-449 ◽

Cited By ~ 1

Author(s):

Dragana Mladenovic ◽

Aleksandra Djukic-Vukovic ◽

Jelena Pejin ◽

Suncica Kocic-Tanackov ◽

Ljiljana Mojovic

Keyword(s):

Lactic Acid ◽

Acid Production ◽

New Technologies ◽

Lactic Acid Production ◽

Physical Nature ◽

Raw Material ◽

Poly Lactic Acid ◽

Immobilized Cell ◽

Waste Products ◽

By Products

In line with the goals of sustainable development and environmental protection today great attention is directed towards new technologies for waste and industrial by-products utilization. Waste products represent potentially good raw material for production other valuable products, such as bioethanol, biogas, biodiesel, organic acids, enzymes, microbial biomass, etc. Since the first industrial production to the present, lactic acid has found wide application in food, cosmetic, pharmaceutical and chemical industries. In recent years, the demand for lactic acid has been increasing considerably owing to its potential use as a monomer for the production of poly-lactic acid (PLA) polymers which are biodegradable and biocompatible with wide applications. Waste and industrial by-products such are whey, molasses, stillage, waste starch and lignocellulosic materials are a good source of fermentable sugars and many other substances of great importance for the growth of microorganisms, such as proteins, minerals and vitamins. Utilization of waste products for production of lactic acid could help to reduce the total cost of lactic acid production and except the economic viability of the process offers a solution of their disposal. Fermentation process depends on chemical and physical nature of feedstocks and the lactic acid producer. This review describes the characteristics, abilities and limits of microorganisms involved in lactic acid production, as well as the characteristics and types of waste products for lactic acid production. The fermentation methods that have been recently reported to improve lactic acid production are summarized and compared. In order to improve processes and productivity, fed-batch fermentation, fermentation with immobilized cell systems and mixed cultures and opportunities of open (non-sterilized) fermentation have been investigated.

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