## 1 Introduction
In another study undertaken by [PERSON] and the colleagues, pure LP cultures generated lactic acid at concentrations ranging from 17.2 to 18.8 g/L, but information on acetic acid production was not provided [13]. The same study further showed that only a small proportion of sugar was utilised by pure LP fermentation, leaving 170 g/L and more residual sugar in the must [13]. The above findings indicate that depletion of sugar relies on the involvement of SC, which could be either inoculated shortly after the addition of LP (reverse inoculation) or simultaneously inoculated (co-inoculation) into the grape must. Varied inoculation regimes may affect fermentation and lactic acid yield, potentially due to the antagonistic activities of yeast against bacteria through direct cell-to-cell contact or producing compounds that inactivate bacterial growth [19]. Among the inhibitory yeast metabolites, ethanol and medium chain fatty acids perturb cell membrane structure, resulting in leakage of intracellular materials and ultimately cell death [19]. In addition, increased acidity resulting from lactic acid production can also exert an inhibitory effect on bacterial growth via impairing hexose metabolism and ATPase activities [20]. Thus, monitoring LP population to ensure efficient lactic fermentation becomes crucial when utilising this tool to achieve biological acidification. Beyond bio-acidification, LP also plays an important role in the development of wine aroma and flavour. LP possesses a wider array of enzymes that can retain functional under typical oenological conditions compared to the commonly used _O. oeni_ in the current winemaking practice [16; 17]. Simultaneous alcoholic and MLF undertaken by co-cultures of LP and SC induced multiple effects on wine composition. Concentrations of major volatiles, including ethyl and acetate esters, fatty acids and higher alcohols can show an increase, decrease or no change compared to the SC monoculture wines [21; 22; 23; 24; 25]. Accordingly, compositional modulations of flavour substances produced through certain metabolic activities of LP may alter sensory perception of the wines [21; 22; 23; 25]. Taken together, both the reverse inoculation and co-inoculation of LP and SC strategies have the potential to induce biological acidification along with modifying wine flavour. Currently, multiple attempts have been made to employ simultaneous inoculation of LP and SC for more efficient and reliable MLF [21; 22; 23; 25; 26]. Nonetheless, these studies focused more on the impact of co-inoculation of SC and LP upon malic acid degradation rather than lactic fermentation. So far, very limited knowledge is available on the applicability of LP to acidify wines beyond its success in lab-scale fermentation trials, including its influence on fermentation, wine composition and flavour. To address these issues, herein we assessed the acidification kinetics and fermentation performance of mixed starter cultures composed of an indigenous LP strain and a commercial SC strain by performing pilot-scale Cabernet Sauvignon viniification. Wines obtained from co-culture fermentations were further assessed for their chemical compositions and sensory outcomes by comparing those parameters to yeast monoculture fermentation with/without chemical acidification. To the best of our knowledge, this study described for the first time on the performance of indigenous LP in inducing biological acidification at pilot-scale red wine production.